dear imgui
CHANGELOG

This document holds the user-facing changelog that we also use in release notes.
We generally fold multiple commits pertaining to the same topic as a single entry.
Changes to backends are also included within the individual .cpp files of each backend.

RELEASE NOTES:          https://github.com/ocornut/imgui/releases
REPORT ISSUES:          https://github.com/ocornut/imgui/issues
DISCUSS, ASK QUESTIONS: https://github.com/ocornut/imgui/discussions
FAQ                     https://www.dearimgui.org/faq/
WIKI                    https://github.com/ocornut/imgui/wiki

WHEN TO UPDATE?

- Keeping your copy of Dear ImGui updated regularly is recommended.
- It is generally safe to sync to the latest commit in master or docking branches
  The library is fairly stable and regressions tends to be fixed fast when reported.

HOW TO UPDATE?

- Overwrite every file except imconfig.h (if you have modified it).
- You may also locally branch to modify imconfig.h and merge latest into your branch.
- Read the `Breaking Changes` section (in imgui.cpp or here in the Changelog).
- If you have a problem with a missing function/symbols, search for its name in the code, there will likely be a comment about it.
- If you are dropping this repository in your codebase, please leave the demo and text files in there, they will be useful.
- You may diff your previous Changelog with the one you just copied and read that diff.
- You may enable `IMGUI_DISABLE_OBSOLETE_FUNCTIONS` in imconfig.h to forcefully disable legacy names and symbols.
  Doing it every once in a while is a good way to make sure you are not using obsolete symbols. Dear ImGui is in active development,
  and API updates have been a little more frequent lately. They are documented below and in imgui.cpp and should not affect all users.
- Please report any issue!


-----------------------------------------------------------------------
 DOCKING+MULTI-VIEWPORT BRANCH (In Progress)
-----------------------------------------------------------------------

DOCKING FEATURES
(see https://github.com/ocornut/imgui/wiki/Docking for quick intro)

- Added Docking system: [BETA] (#2109, #351)
  - Added ImGuiConfigFlags_DockingEnable flag to enable Docking.
    Set with `io.ConfigFlags |= ImGuiConfigFlags_DockingEnable;`.
  - Added DockSpace(), DockSpaceOverViewport() API.
  - Added ImGuiDockNodeFlags flags for DockSpace().
  - Added SetNextWindowDockID(), SetNextWindowClass() API.
  - Added GetWindowDockID(), IsWindowDocked() API.
  - Added ImGuiWindowFlags_NoDocking window flag to disable the possibility for a window to be docked.
    Popup, Menu and Child windows always have the ImGuiWindowFlags_NoDocking flag set.
  - Added ImGuiWindowClass to specify advanced docking/viewport related flags via SetNextWindowClass().
  - Added io.ConfigDockingNoSplit option.
  - Added io.ConfigDockingWithShift option.
  - Added io.ConfigDockingAlwaysTabBar option.
  - Added io.ConfigDockingTransparentPayload option.
  - Style: Added ImGuiCol_DockingPreview, ImGuiCol_DockingEmptyBg colors.
  - Demo: Added "DockSpace" example app showcasing use of explicit dockspace nodes.

MULTI-VIEWPORT FEATURES
(see https://github.com/ocornut/imgui/wiki/Multi-Viewports for quick intro)

Breaking Changes:

- IMPORTANT: When multi-viewports are enabled (with io.ConfigFlags |= ImGuiConfigFlags_ViewportsEnable),
  all coordinates/positions will be in your natural OS coordinates space. It means that:
   - Reference to hard-coded positions such as in SetNextWindowPos(ImVec2(0,0)) are _probably_ not what you want anymore.
     Use GetMainViewport()->Pos to offset hard-coded positions, e.g. SetNextWindowPos(GetMainViewport()->Pos).
   - Likewise io.MousePos and GetMousePos() will use OS coordinates.
     If you query mouse positions to interact with non-imgui coordinates you will need to offset them.
     e.g. subtract GetWindowViewport()->Pos.
- IO: Moved IME support functions from io.ImeSetInputScreenPosFn, io.ImeWindowHandle to the PlatformIO api.
- IO: Removed io.DisplayVisibleMin, io.DisplayVisibleMax settings (they were marked obsoleted, used to clip within the (0,0)..(DisplaySize) range).

Other changes:
(FIXME: This need a fuller explanation!)

- Added ImGuiPlatformIO structure and GetPlatformIO().
  - Similarly to ImGuiIO and GetIO(), this structure is the main point of communication for backends supporting multi-viewports.
  - Backend sets functions in ImGuiPlatformIO to manipulate platform windows.
  - ImGuiPlatformIO::Monitors is a list of platform monitors (input from backend)
  - ImGuiPlatformIO::Viewports is a list of viewports (output from dear imgui)
- Added ImGuiPlatformMonitor to feed OS monitor information in the ImGuiPlatformIO::Monitors.
- Added GetWindowViewport(), SetNextWindowViewport().
- Added GetWindowDpiScale().
- Added GetOverlayDrawList(ImGuiViewport* viewport).
  The no-parameter version of GetOverlayDrawList() return the overlay for the current window's viewport.
- Added UpdatePlatformWindows(), RenderPlatformWindowsDefault(), DestroyPlatformWindows() for usage in application setup.
- Added FindViewportByID(), FindViewportByPlatformHandle() for usage by backends.
- Added ImGuiConfigFlags_ViewportsEnable configuration flag and other viewport options.
- Added io.ConfigViewportsNoAutoMerge option.
- Added io.ConfigViewportsNoTaskBarIcon option.
- Added io.ConfigViewportsNoDecoration option.
- Added io.ConfigViewportsNoDefaultParent option.
- Added ImGuiBackendFlags_PlatformHasViewports, ImGuiBackendFlags_RendererHasViewports, ImGuiBackendFlags_HasMouseHoveredViewport backend flags.
- Added io.MouseHoveredViewport (optional _even_ for multi-viewport support, tied to ImGuiBackendFlags_HasMouseHoveredViewport flag).
- Expanded ImGuiViewport structure, ImGuiViewportFlags flags.
- Added ImGuiWindowClass and SetNextWindowClass() for passing viewport related hints to the OS/platform back-end.
- Examples: Renderer: OpenGL2, OpenGL3, DirectX9, DirectX10, DirectX11, DirectX12, Vulkan: Added support for multi-viewports.
- Examples: Platforms: Win32, GLFW, SDL2: Added support for multi-viewports.
  Note that Linux/Mac still have inconsistent support for multi-viewports. If you want to help see https://github.com/ocornut/imgui/issues/2117.


-----------------------------------------------------------------------
 VERSION 1.84 WIP (In Progress)
-----------------------------------------------------------------------

Other Changes:
- TabBar: Fixed using more than 32 KB-worth of tab names. (#4176)
- Tables: Added ImGuiTableColumnFlags_Disabled acting a master disable over (hidden from user/context menu). (#3935)
- Tables: Clarified that TableSetColumnEnabled() requires the table to use the ImGuiTableFlags_Hideable flag,
  because it manipulates the user-accessible show/hide state. (#3935)
- Tables: Added ImGuiTableColumnFlags_NoHeaderLabel to request TableHeadersRow() to not submit label for a column.
  Convenient for some small columns. Name will still appear in context menu. (#4206).
- Tables: Fix columns order on TableSetupScrollFreeze() if previous data got frozen columns out of their section.
- Fixed printf-style format checks on non-MinGW flavors. (#4183, #3592)
- Demo: Fixed requirement in 1.83 to link with imgui_demo.cpp if IMGUI_DISABLE_METRICS_WINDOW is not set. (#4171)
  Normally the right way to disable compiling the demo is to set IMGUI_DISABLE_DEMO_WINDOWS, but we want to avoid
  implying that the file is required.
- Backends: Win32: Rework to handle certains Windows 8.1/10 features without a manifest. (#4200, #4191)
  - ImGui_ImplWin32_GetDpiScaleForMonitor() will handle per-monitor DPI on Windows 10 without a manifest.
  - ImGui_ImplWin32_EnableDpiAwareness() will call SetProcessDpiAwareness() fallback on Windows 8.1 without a manifest.
- Backends: OpenGL3: Handle GL_CLIP_ORIGIN on <4.5 contexts if "GL_ARB_clip_control" extension is detected. (#4170, #3998)
- Examples: Updated all .vcxproj to VS2015 (toolset v140) to facilitate usage with vcpkg.
- Examples: SDL2: Accomodate for vcpkg install having headers in SDL2/SDL.h vs SDL.h.

Docking+Viewports Branch:

- Docking: Clicking on the right-most close button of a docking node closes all windows. (#4186)
- Docking: Fix IsWindowAppearing() and ImGuiCond_Appearing on docked windows. (#4177, #3982, #1497, #1061)
- Backends: Vulkan: Fix the use of the incorrect fence for secondary viewports. (#4208) [@FunMiles]


-----------------------------------------------------------------------
 VERSION 1.83 (Released 2011-05-24)
-----------------------------------------------------------------------

Decorated log: https://github.com/ocornut/imgui/releases/tag/v1.83

Breaking Changes:

- Backends: Obsoleted direct access to ImDrawCmd::TextureId in favor of calling ImDrawCmd::GetTexID(). (#3761) [@thedmd]
  - If you are using official backends from the source tree: you have nothing to do.
  - If you copied old backend code or using your own: change access to draw_cmd->TextureId to draw_cmd->GetTexID().
  Why are we doing this?
  - This change will be required in the future when adding support for incremental texture atlas updates.
  - Please note this won't break soon, but we are making the change ahead of time.

Other Changes:

- Scrolling: Fix scroll tracking with e.g. SetScrollHereX/Y() when WindowPadding < ItemSpacing.
- Scrolling: Fix scroll snapping on edge of scroll region when both scrollbars are enabled.
- Scrolling: Fix mouse wheel axis swap when using SHIFT on macOS (system already does it). (#4010)
- Window: Fix IsWindowAppearing() from returning true twice in most cases. (#3982, #1497, #1061)
- Nav: Fixed toggling menu layer while an InputText() is active not stealing active id. (#787)
- Nav: Fixed pressing Escape to leave menu layer while in a popup or child window. (#787)
- Nav, InputText: Fixed accidental menu toggling while typing non-ascii characters using AltGR. [@rokups] (#370)
- Nav: Fixed using SetItemDefaultFocus() on windows with _NavFlattened flag. (#787)
- Nav: Fixed Tabbing initial activation from skipping the first item if it is tabbable through. (#787)
- Nav: Fixed fast CTRL+Tab (where keys are only held for one single frame) from properly enabling the
  menu layer of target window if it doesn't have other active layers.
- Tables: Expose TableSetColumnEnabled() in public api. (#3935)
- Tables: Better preserve widths when columns count changes. (#4046)
- Tables: Sharing more memory buffers between tables, reducing general memory footprints. (#3740)
- TabBar: Fixed mouse reordering with very fast movements (e.g. crossing multiple tabs in a single
  frame and then immediately standing still (would only affect automation/bots). [@rokups]
- Menus: made MenuItem() in a menu bar reflect the 'selected' argument with a highlight. (#4128) [@mattelegende]
- Drags, Sliders, Inputs: Specifying a NULL format to Float functions default them to "%.3f" to be
  consistent with the compile-time default. (#3922)
- DragScalar: Add default value for v_speed argument to match higher-level functions. (#3922) [@eliasdaler]
- ColorEdit4: Alpha default to 255 (instead of 0) when omitted in hex input. (#3973) [@squadack]
- InputText: Do not filter private unicode codepoints (e.g. icons) when pasted from clipboard. (#4005) [@dougbinks]
- InputText: Align caret/cursor to pixel coordinates. (#4080) [@elvissteinjr]
- InputText: Fixed CTRL+Arrow or OSX double-click leaking the presence of spaces when ImGuiInputTextFlags_Password
  is used. (#4155, #4156) [@michael-swan]
- LabelText: Fixed clipping of multi-line value text when label is single-line. (#4004)
- LabelText: Fixed vertical alignment of single-line value text when label is multi-line. (#4004)
- Combos: Changed the combo popup to use a different id to also using a context menu with the default item id.
  Fixed using BeginPopupContextItem() with no parameter after a combo. (#4167)
- Popups: Added 'OpenPopup(ImGuiID id)' overload to facilitate calling from nested stacks. (#3993, #331) [@zlash]
- Tweak computation of io.Framerate so it is less biased toward high-values in the first 120 frames. (#4138)
- Optimization: Disabling some of MSVC most aggressive Debug runtime checks for some simple/low-level functions
  (e.g. ImVec2, ImVector) leading to a 10-20% increase of performances with MSVC "default" Debug settings.
- ImDrawList: Add and use SSE-enabled ImRsqrt() in place of 1.0f / ImSqrt(). (#4091) [@wolfpld]
- ImDrawList: Fixed/improved thickness of thick strokes with sharp angles. (#4053, #3366, #2964, #2868, #2518, #2183)
  Effectively introduced a regression in 1.67 (Jan 2019), and a fix in 1.70 (Apr 2019) but the fix wasn't actually on
  par with original version. Now incorporating the correct revert.
- ImDrawList: Fixed PathArcTo() regression from 1.82 preventing use of counter-clockwise angles. (#4030, #3491) [@thedmd]
- Demo: Improved popups demo and comments.
- Metrics: Added "Fonts" section with same information as available in "Style Editor">"Fonts".
- Backends: SDL: Rework global mouse pos availability check listing supported platforms explicitly,
  effectively fixing mouse access on Raspberry Pi. (#2837, #3950) [@lethal-guitar, @hinxx]
- Backends: Win32: Clearing keyboard down array when losing focus (WM_KILLFOCUS). (#2062, #3532, #3961)
  [@1025798851]
- Backends: OSX: Fix keys remaining stuck when CMD-tabbing to a different application. (#3832) [@rokups]
- Backends: DirectX9: calling IDirect3DStateBlock9::Capture() after CreateStateBlock() which appears to
  workaround/fix state restoring issues. Unknown exactly why so, bit of a cargo-cult fix. (#3857)
- Backends: DirectX9: explicitly setting up more graphics states to increase compatibility with unusual
  non-default states. (#4063)
- Backends: DirectX10, DirectX11: fixed a crash when backing/restoring state if nothing is bound when
  entering the rendering function. (#4045) [@Nemirtingas]
- Backends: GLFW: Adding bound check in KeyCallback because GLFW appears to send -1 on some setups. [#4124]
- Backends: Vulkan: Fix mapped memory Vulkan validation error when buffer sizes are not multiple of
  VkPhysicalDeviceLimits::nonCoherentAtomSize. (#3957) [@AgentX1994]
- Backends: WebGPU: Update to latest specs (Chrome Canary 92 and Emscripten 2.0.20). (#4116, #3632) [@bfierz, @Kangz]
- Backends: OpenGL3: Don't try to read GL_CLIP_ORIGIN unless we're OpenGL 4.5. (#3998, #2366, #2186) [@s7jones]
- Examples: OpenGL: Add OpenGL ES 2.0 support to modern GL examples. (#2837, #3951) [@lethal-guitar, @hinxx]
- Examples: Vulkan: Rebuild swapchain on VK_SUBOPTIMAL_KHR. (#3881)
- Examples: Vulkan: Prefer using discrete GPU if there are more than one available. (#4012) [@rokups]
- Examples: SDL2: Link with shell32.lib required by SDL2main.lib since SDL 2.0.12. [#3988]
- Examples: Android: Make Android example build compatible with Gradle 7.0. (#3446)
- Docs: Improvements to description of using colored glyphs/emojis. (#4169, #3369)
- Docs: Improvements to minor mistakes in documentation comments (#3923) [@ANF-Studios]

Docking+Viewports Branch:

- [Breaking] Removed io.ConfigDockingWithShift config option. Behavior always equivalent to having the
  option set to false (dock/undock by default, hold shift to avoid docking). (#2109)
- Docking: DockSpace() returns its node ID.
- Docking: Dockspace() never draws a background. (#3924)
- Docking: Undocking nodes/windows covering most of the monitor max their size down to 90% to ease manipulations.
- Docking: Docking node tab bar honors ItemInnerSpacing.x before first tab. (#4130)
- Docking: Tweak rendering and alignment of dock node menu marker. (#4130)
- Docking: Fixed restoring of tab order within a dockspace or a split node.
- Docking: Fixed reappearing docked windows with no close button showing a tab with extraneous space for one frame.
- Docking: Fixed multiple simultaneously reappearing window from appearing undocked for one frame.
- Viewports: Hotfix for crash in monitor array access, caused by 4b9bc4902. (#3967)
- Backends, Viewports: GLFW: Add a workaround for stuck keys after closing a GLFW window (#3837).
- Backends, Viewports: Vulkan: Rebuild swapchain on VK_SUBOPTIMAL_KHR. (#3881)


-----------------------------------------------------------------------
 VERSION 1.82 (Released 2021-02-15)
-----------------------------------------------------------------------

Decorated log: https://github.com/ocornut/imgui/releases/tag/v1.82

Breaking Changes:

- Removed redirecting functions/enums names that were marked obsolete in 1.66 (September 2018):
    - ImGui::SetScrollHere() --> use ImGui::SetScrollHereY()
- ImDrawList: upgraded AddPolyline()/PathStroke()'s "bool closed" parameter to use "ImDrawFlags flags".
    - bool closed = false    --> use ImDrawFlags_None, or 0
    - bool closed = true     --> use ImDrawFlags_Closed
  The matching ImDrawFlags_Closed value is guaranteed to always stay == 1 in the future.
  Difference may not be noticeable for most but zealous type-checking tools may report a need to change.
- ImDrawList: upgraded AddRect(), AddRectFilled(), PathRect() to use ImDrawFlags instead of ImDrawCornersFlags.
    - ImDrawCornerFlags_TopLeft  --> use ImDrawFlags_RoundCornersTopLeft
    - ImDrawCornerFlags_BotRight --> use ImDrawFlags_RoundCornersBottomRight
    - ImDrawCornerFlags_None     --> use ImDrawFlags_RoundCornersNone etc.
  Flags now sanely defaults to 0 instead of 0x0F, consistent with all other flags in the API.
  IMPORTANT: The default with rounding > 0.0f is now "round all corners" vs old implicit "round no corners":
    - rounding == 0.0f + flags == 0 --> meant no rounding  --> unchanged (common use)
    - rounding  > 0.0f + flags != 0 --> meant rounding     --> unchanged (common use)
    - rounding == 0.0f + flags != 0 --> meant no rounding  --> unchanged (unlikely use)
    - rounding  > 0.0f + flags == 0 --> meant no rounding  --> BREAKING (unlikely use)!
       - this ONLY matters for hardcoded use of 0 with rounding > 0.0f.
       - fix by using named ImDrawFlags_RoundCornersNone or rounding == 0.0f!
       - this is technically the only real breaking change which we can't solve automatically (it's also uncommon).
  The old ImDrawCornersFlags used awkward default values of ~0 or 0xF (4 lower bits set) to signify "round all corners"
  and we sometimes encouraged using them as shortcuts. As a result the legacy path still support use of hardcoded ~0
  or any value from 0x1 or 0xF. They will behave the same with legacy paths enabled (will assert otherwise).
  Courtesy of legacy untangling commity: [@rokups, @ocornut, @thedmd]
- ImDrawList: clarified that PathArcTo()/PathArcToFast() won't render with radius < 0.0f. Previously it sorts
  of accidentally worked but would lead to counter-clockwise paths which and have an effect on anti-aliasing.
- InputText: renamed ImGuiInputTextFlags_AlwaysInsertMode to ImGuiInputTextFlags_AlwaysOverwrite, old name was an
  incorrect description of behavior. Was ostly used by memory editor. Kept inline redirection function. (#2863)
- Moved 'misc/natvis/imgui.natvis' to 'misc/debuggers/imgui.natvis' as we will provide scripts for other debuggers.
- Style: renamed rarely used style.CircleSegmentMaxError (old default = 1.60f)
  to style.CircleTessellationMaxError (new default = 0.30f) as its meaning changed. (#3808) [@thedmd]
- Win32+MinGW: Re-enabled IME functions by default even under MinGW. In July 2016, issue #738 had me incorrectly
  disable those default functions for MinGW. MinGW users should: either link with -limm32, either set their
  imconfig file with '#define IMGUI_DISABLE_WIN32_DEFAULT_IME_FUNCTIONS'. (#2590, #738) [@actboy168]
- Backends: Win32: Pragma linking with dwmapi.lib (Vista-era, ~9 kb). MinGW users will need to link with -ldwmapi.

Other Changes:

- Window, Nav: Fixed crash when calling SetWindowFocus(NULL) at the time a new window appears. (#3865) [@nem0]
- Window: Shrink close button hit-testing region when it covers an abnormally high portion of the window visible
  area (e.g. when window is collapsed + moved in a corner) to facilitate moving the window away. (#3825)
- Nav: Various fixes for losing gamepad/keyboard navigation reference point when a window reappears or
  when it appears while gamepad/keyboard are not being used. (#787)
- Drags: Fixed crash when using DragScalar() directly (not via common wrapper like DragFloat() etc.)
  with ImGuiSliderFlags_AlwaysClamp + only one of either p_min or p_max set. (#3824) [@harry75369]
- Drags, Sliders: Fixed a bug where editing value would use wrong number if there were digits right after
  format specifier (e.g. using "%f123" as a format string). [@rokups]
- Drags, Sliders: Fixed a bug where using custom formatting flags (',$,_) supported by stb_sprintf.h
  would cause incorrect value to be displayed. (#3604) [@rokups]
- Drags, Sliders: Support ImGuiSliderFlags_Logarithmic flag with integers. Because why not? (#3786)
- Tables: Fixed unaligned accesses when using TableSetBgColor(ImGuiTableBgTarget_CellBg). (#3872)
- IsItemHovered(): fixed return value false positive when used after EndChild(), EndGroup() or widgets using
  either of them, when the hovered location is located within a child window, e.g. InputTextMultiline().
  This is intended to have no side effects, but brace yourself for the possible comeback.. (#3851, #1370)
- Drag and Drop: can use BeginDragDropSource() for other than the left mouse button as long as the item
  has an ID (for ID-less items will add new functionalities later). (#1637, #3885)
- ImFontAtlas: Added 'bool TexPixelsUseColors' output to help backend decide of underlying texture format. (#3369)
  This can currently only ever be set by the Freetype renderer.
- imgui_freetype: Added ImGuiFreeTypeBuilderFlags_Bitmap flag to request Freetype loading bitmap data.
  This may have an effect on size and must be called with correct size values. (#3879) [@metarutaiga]
- ImDrawList: PathArcTo() now supports "int num_segments = 0" (new default) and adaptively tessellate.
  The adaptive tessellation uses look up tables, tends to be faster than old PathArcTo() while maintaining
  quality for large arcs (tessellation quality derived from "style.CircleTessellationMaxError") (#3491) [@thedmd]
- ImDrawList: PathArcToFast() also adaptively tessellate efficiently. This means that large rounded corners
  in e.g. hi-dpi settings will generally look better. (#3491) [@thedmd]
- ImDrawList: AddCircle, AddCircleFilled(): Tweaked default segment count calculation to honor MaxError
  with more accuracy. Made default segment count always even for better looking result. (#3808) [@thedmd]
- Misc: Added GetAllocatorFunctions() to facilitate sharing allocators across DLL boundaries. (#3836)
- Misc: Added 'debuggers/imgui.gdb' and 'debuggers/imgui.natstepfilter' (along with existing 'imgui.natvis')
  scripts to configure popular debuggers into skipping trivial functions when using StepInto. [@rokups]
- Backends: Android: Added native Android backend. (#3446) [@duddel]
- Backends: Win32: Added ImGui_ImplWin32_EnableAlphaCompositing() to facilitate experimenting with
  alpha compositing and transparent windows. (#2766, #3447 etc.).
- Backends: OpenGL, Vulkan, DX9, DX10, DX11, DX12, Metal, WebGPU, Allegro: Rework blending equation to
  preserve alpha in output buffer (using SrcBlendAlpha = ONE, DstBlendAlpha = ONE_MINUS_SRC_ALPHA consistently
  accross all backends), facilitating compositing of the output buffer with another buffer.
  (#2693, #2764, #2766, #2873, #3447, #3813, #3816) [@ocornut, @thedmd, @ShawnM427, @Ubpa, @aiekick]
- Backends: DX9: Fix to support IMGUI_USE_BGRA_PACKED_COLOR. (#3844) [@Xiliusha]
- Backends: DX9: Fix to support colored glyphs, using newly introduced 'TexPixelsUseColors' info. (#3844)
- Examples: Android: Added Android + GL ES3 example. (#3446) [@duddel]
- Examples: Reworked setup of clear color to be compatible with transparent values.
- CI: Use a dedicated "scheduled" workflow to trigger scheduled builds. Forks may disable this workflow if
  scheduled builds builds are not required. [@rokups]
- Log/Capture: Added LogTextV, a va_list variant of LogText. [@PathogenDavid]

Docking+Viewports Branch:

- Viewports: Fix setting of ImGuiViewportFlags_NoRendererClear. (#3213)
- Viewports: Added GetViewportPlatformMonitor() with a safety net to keep code portable.
- Viewports, Backends: SDL: Fix missing ImGuiBackendFlags_HasSetMousePos flag in docking branch.
- Viewports, Backends: GLFW: Fix application of WantSetMousePos. (#1542, #787)


-----------------------------------------------------------------------
 VERSION 1.81 (Released 2021-02-10)
-----------------------------------------------------------------------

Decorated log: https://github.com/ocornut/imgui/releases/tag/v1.81

Breaking Changes:

- ListBox helpers:
  - Renamed ListBoxHeader(const char* label, ImVec2 size) to BeginListBox().
  - Renamed ListBoxFooter() to EndListBox().
  - Removed ListBoxHeader(const char* label, int items_count, int height_in_items = -1) in favor of specifying size.
    In the redirection function, made vertical padding consistent regardless of (items_count <= height_in_items) or not.
  - Kept inline redirection function for all threes (will obsolete).
- imgui_freetype:
  - Removed ImGuiFreeType::BuildFontAtlas(). Kept inline redirection function.
    Prefer using '#define IMGUI_ENABLE_FREETYPE', but there's a runtime selection path available too.
  - The shared extra flags parameters (very rarely used) are now stored in ImFontAtlas::FontBuilderFlags.
  - Renamed ImFontConfig::RasterizerFlags (used by FreeType) to ImFontConfig::FontBuilderFlags.
  - Renamed ImGuiFreeType::XXX flags to ImGuiFreeTypeBuilderFlags_XXX for consistency with other API.

Other Changes:

- Viewports Added ImGui::GetMainViewport() as a way to get the bounds and work area of the host display. (#3789, #1542)
  - In 'master' branch or without multi-viewports feature enabled:
    - GetMainViewport()->Pos is always == (0,0)
    - GetMainViewport()->Size is always == io.DisplaySize
  - In 'docking' branch and with the multi-viewports feature enabled:
    - GetMainViewport() will return information from your host Platform Window.
    - In the future, we will support a "no main viewport" mode and this may return bounds of your main monitor.
  - For forward compatibility with multi-viewports/multi-monitors:
     - Code using (0,0) as a way to signify "upper-left of the host window" should use GetMainViewport()->Pos.
     - Code using io.DisplaySize as a way to signify "size of the host window" should use GetMainViewport()->Size.
  - We are also exposing a work area in ImGuiViewport ('WorkPos', 'WorkSize' vs 'Pos', 'Size' for full area):
     - For a Platform Window, the work area is generally the full area minus space used by menu-bars.
     - For a Platform Monitor, the work area is generally the full area minus space used by task-bars.
  - All of this has been the case in 'docking' branch for a long time. What we've done is merely merging
    a small chunk of the multi-viewport logic into 'master' to standardize some concepts ahead of time.
- Tables: Fixed PopItemWidth() or multi-components items not restoring per-colum ItemWidth correctly. (#3760)
- Window: Fixed minor title bar text clipping issue when FramePadding is small/zero and there are no
  close button in the window. (#3731)
- SliderInt: Fixed click/drag when v_min==v_max from setting the value to zero. (#3774) [@erwincoumans]
  Would also repro with DragFloat() when using ImGuiSliderFlags_Logarithmic with v_min==v_max.
- Menus: Fixed an issue with child-menu auto sizing (issue introduced in 1.80 on 2021/01/25) (#3779)
- InputText: Fixed slightly off ScrollX tracking, noticeable with large values of FramePadding.x. (#3781)
- InputText: Multiline: Fixed padding/cliprect not precisely matching single-line version. (#3781)
- InputText: Multiline: Fixed FramePadding.y worth of vertical offset when aiming with mouse.
- ListBox: Tweaked default height calculation.
- Fonts: imgui_freetype: Facilitated using FreeType integration: [@Xipiryon, @ocornut]
  - Use '#define IMGUI_ENABLE_FREETYPE' in imconfig.h should make it work with no other modifications
    other than compiling misc/freetype/imgui_freetype.cpp and linking with FreeType.
  - Use '#define IMGUI_ENABLE_STB_TRUETYPE' if you somehow need the stb_truetype rasterizer to be
    compiled in along with the FreeType one, otherwise it is enabled by default.
- Fonts: imgui_freetype: Added support for colored glyphs as supported by Freetype 2.10+ (for .ttf using CPAL/COLR
  tables only). Enable the ImGuiFreeTypeBuilderFlags_LoadColor on a given font. Atlas always output directly
  as RGBA8 in this situation. Likely to make sense with IMGUI_USE_WCHAR32. (#3369) [@pshurgal]
- Fonts: Fixed CalcTextSize() width rounding so it behaves more like a ceil. This is in order for text wrapping
  to have enough space when provided width precisely calculated with CalcTextSize().x. (#3776)
  Note that the rounding of either positions and widths are technically undesirable (e.g. #3437, #791) but
  variety of code is currently on it so we are first fixing current behavior before we'll eventually change it.
- Log/Capture: Fix various new line/spacing issue when logging widgets. [@Xipiryon, @ocornut]
- Log/Capture: Improved the ASCII look of various widgets, making large dumps more easily human readable.
- ImDrawList: Fixed AddCircle()/AddCircleFilled() with (rad > 0.0f && rad < 1.0f && num_segments == 0). (#3738)
  Would lead to a buffer read overflow.
- ImDrawList: Clarified PathArcTo() need for a_min <= a_max with an assert.
- ImDrawList: Fixed PathArcToFast() handling of a_min > a_max.
- Metrics: Back-ported "Viewports" debug visualizer from 'docking' branch.
- Demo: Added 'Examples->Fullscreen Window' demo using GetMainViewport() values. (#3789)
- Demo: 'Simple Overlay' demo now moves under main menu-bar (if any) using GetMainViewport()'s work area.
- Backends: Win32: Dynamically loading XInput DLL instead of linking with it, facilitate compiling with
  old WindowSDK versions or running on Windows 7. (#3646, #3645, #3248, #2716) [@Demonese]
- Backends: Vulkan: Add support for custom Vulkan function loader and VK_NO_PROTOTYPES. (#3759, #3227) [@Hossein-Noroozpour]
  User needs to call ImGui_ImplVulkan_LoadFunctions() with their custom loader prior to other functions.
- Backends: Metal: Fixed texture storage mode when building on Mac Catalyst. (#3748) [@Belinsky-L-V]
- Backends: OSX: Fixed mouse position not being reported when mouse buttons other than left one are down. (#3762) [@rokups]
- Backends: WebGPU: Added enderer backend for WebGPU support (imgui_impl_wgpu.cpp) (#3632) [@bfierz]
  Please note that WebGPU is currently experimental, will not run on non-beta browsers, and may break.
- Examples: WebGPU: Added Emscripten+WebGPU example. (#3632) [@bfierz]
- Backends: GLFW: Added ImGui_ImplGlfw_InitForOther() initialization call to use with non OpenGL API. (#3632)

Docking+Viewports Branch:

- Docking: Fix losing docking information on closed windows for which the hosting node was split. (#3716) [@GamingMinds-DanielC]
- Docking: Fix gap in hit test hole when using ImGuiDockNodeFlags_PassthruCentralNode touching the edge of a viewport. (#3733)
- Viewports: (Breaking) removed ImGuiPlatformIO::MainViewport which is now pretty much unused and duplicate
  (and misleading as we will evolve the concept).
- Viewports: (Breaking) turned ImGuiViewport::GetWorkPos(), ImGuiViewport::GetWorkSize() into regular fields
  (WorkPos, WorkSize) before exposing in master branch.
- Viewports: Fix issue inferring viewport z-order when new popups gets created. (#3734) + Metrics updates.
- Viewports, Backends: Vulkan: handle VK_ERROR_OUT_OF_DATE_KHR when resizing secondary viewport (#3766, #3758)


-----------------------------------------------------------------------
 VERSION 1.80 (Released 2021-01-21)
-----------------------------------------------------------------------

Decorated log: https://github.com/ocornut/imgui/releases/tag/v1.80

Breaking Changes:

- Added imgui_tables.cpp file! Manually constructed project files will need the new file added! (#3740)
- Backends: moved all backends files (imgui_impl_XXXX.cpp, imgui_impl_XXXX.h) from examples/ to backends/. (#3513)
- Renamed ImDrawList::AddBezierCurve() to ImDrawList::AddBezierCubic(). Kept inline redirection function (will obsolete).
- Renamed ImDrawList::PathBezierCurveTo() to ImDrawList::PathBezierCubicCurveTo(). Kept inline redirection function (will obsolete).
- Removed redirecting functions/enums names that were marked obsolete in 1.60 (April 2018):
  - io.RenderDrawListsFn pointer                -> use ImGui::GetDrawData() value and call the render function of your backend
  - ImGui::IsAnyWindowFocused()                 -> use ImGui::IsWindowFocused(ImGuiFocusedFlags_AnyWindow)
  - ImGui::IsAnyWindowHovered()                 -> use ImGui::IsWindowHovered(ImGuiHoveredFlags_AnyWindow)
  - ImGuiStyleVar_Count_                        -> use ImGuiStyleVar_COUNT
  - ImGuiMouseCursor_Count_                     -> use ImGuiMouseCursor_COUNT
- Removed redirecting functions/enums names that were marked obsolete in 1.61 (May 2018):
  - InputFloat (... int decimal_precision ...)  -> use InputFloat (... const char* format ...) with format = "%.Xf" where X was value for decimal_precision.
  - same for InputFloat2()/InputFloat3()/InputFloat4() variants taking a `int decimal_precision` parameter.
- Removed redirecting functions/enums names that were marked obsolete in 1.63 (August 2018):
  - ImGui::IsItemDeactivatedAfterChange()       -> use ImGui::IsItemDeactivatedAfterEdit().
  - ImGuiCol_ModalWindowDarkening               -> use ImGuiCol_ModalWindowDimBg
  - ImGuiInputTextCallback                      -> use ImGuiTextEditCallback
  - ImGuiInputTextCallbackData                  -> use ImGuiTextEditCallbackData
- If you were still using the old names, while you are cleaning up, considering enabling
  IMGUI_DISABLE_OBSOLETE_FUNCTIONS in imconfig.h even temporarily to have a pass at finding
  and removing up old API calls, if any remaining.
- Internals: Columns: renamed undocumented/internals ImGuiColumnsFlags_* to ImGuiOldColumnFlags_* to reduce
  confusion with Tables API. Keep redirection enums (will obsolete). (#125, #513, #913, #1204, #1444, #2142, #2707)
- Renamed io.ConfigWindowsMemoryCompactTimer to io.ConfigMemoryCompactTimer as the feature now applies
  to other data structures. (#2636)

Other Changes:

- Tables: added new Tables Beta API as a replacement for old Columns. (#3740, #2957, #125)
  Check out 'Demo->Tables' for many demos.
  Read API comments in imgui.h for details. Read extra commentary in imgui_tables.cpp.
  - Added 16 functions:
     - BeginTable(), EndTable()
     - TableNextRow(), TableNextColumn(), TableSetColumnIndex()
     - TableSetupColumn(), TableSetupScrollFreeze()
     - TableHeadersRow(), TableHeader()
     - TableGetRowIndex(), TableGetColumnCount(), TableGetColumnIndex(), TableGetColumnName(), TableGetColumnFlags()
     - TableGetSortSpecs(), TableSetBgColor()
  - Added 3 flags sets:
    - ImGuiTableFlags (29 flags for: features, decorations, sizing policies, padding, clipping, scrolling, sorting etc.)
    - ImGuiTableColumnFlags (24 flags for: width policies, default settings, sorting options, indentation options etc.)
    - ImGuiTableRowFlags (1 flag for: header row)
  - Added 2 structures: ImGuiTableSortSpecs, ImGuiTableColumnSortSpecs
  - Added 2 enums: ImGuiSortDirection, ImGuiTableBgTarget
  - Added 1 style variable: ImGuiStyleVar_CellPadding
  - Added 5 style colors: ImGuiCol_TableHeaderBg, ImGuiCol_TableBorderStrong, ImGuiCol_TableBorderLight, ImGuiCol_TableRowBg, ImGuiCol_TableRowBgAlt.
- Tab Bar: Made it possible to append to an existing tab bar by calling BeginTabBar()/EndTabBar() again.
- Tab Bar: Fixed using more than 128 tabs in a tab bar (scrolling policy recommended).
- Tab Bar: Do not display a tooltip if the name already fits over a given tab. (#3521)
- Tab Bar: Fixed minor/unlikely bug skipping over a button when scrolling left with arrows.
- Tab Bar: Requested ideal content size (for auto-fit) doesn't affect horizontal scrolling. (#3414)
- Drag and Drop: Fix losing drop source ActiveID (and often source tooltip) when opening a TreeNode()
  or CollapsingHeader() while dragging. (#1738)
- Drag and Drop: Fix drag and drop to tie same-size drop targets by chosen the later one. Fixes dragging
  into a full-window-sized dockspace inside a zero-padded window. (#3519, #2717) [@Black-Cat]
- Checkbox: Added CheckboxFlags() helper with int* type (internals have a template version, not exposed).
- Clipper: Fixed incorrect end-list positioning when using ImGuiListClipper with 1 item (bug in 1.79). (#3663) [@nyorain]
- InputText: Fixed updating cursor/selection position when a callback altered the buffer in a way
  where the byte count is unchanged but the decoded character count changes. (#3587) [@gqw]
- InputText: Fixed switching from single to multi-line while preserving same ID.
- Combo: Fixed using IsItemEdited() after Combo() not matching the return value from Combo(). (#2034)
- DragFloat, DragInt: very slightly increased mouse drag threshold + expressing it as a factor of default value.
- DragFloat, DragInt: added experimental io.ConfigDragClickToInputText feature to enable turning DragXXX widgets
  into text input with a simple mouse click-release (without moving). (#3737)
- Nav: Fixed IsItemFocused() from returning false when Nav highlight is hidden because mouse has moved.
  It's essentially been always the case but it doesn't make much sense. Instead we will aim at exposing
  feedback and control of keyboard/gamepad navigation highlight and mouse hover disable flag. (#787, #2048)
- Metrics: Fixed mishandling of ImDrawCmd::VtxOffset in wireframe mesh renderer.
- Metrics: Rebranded as "Dear ImGui Metrics/Debugger" to clarify its purpose.
- ImDrawList: Added ImDrawList::AddQuadBezierCurve(), ImDrawList::PathQuadBezierCurveTo() quadratic bezier
  helpers. (#3127, #3664, #3665) [@aiekick]
- Fonts: Updated GetGlyphRangesJapanese() to include a larger 2999 ideograms selection of Joyo/Jinmeiyo
  kanjis, from the previous 1946 ideograms selection. This will consume a some more memory but be generally
  much more fitting for Japanese display, until we switch to a more dynamic atlas. (#3627) [@vaiorabbit]
- Log/Capture: fix capture to work on clipped child windows.
- Misc: Made the ItemFlags stack shared, so effectively the ButtonRepeat/AllowKeyboardFocus states
  (and others exposed in internals such as PushItemFlag) are inherited by stacked Begin/End pairs,
  vs previously a non-child stacked Begin() would reset those flags back to zero for the stacked window.
- Misc: Replaced UTF-8 decoder with one based on branchless one by Christopher Wellons. [@rokups]
  Super minor fix handling incomplete UTF-8 contents: if input does not contain enough bytes, decoder
  returns IM_UNICODE_CODEPOINT_INVALID and consume remaining bytes (vs old decoded consumed only 1 byte).
- Misc: Fix format warnings when using gnu printf extensions in a setup that supports them (gcc/mingw). (#3592)
- Misc: Made EndFrame() assertion for key modifiers being unchanged during the frame (added in 1.76) more
  lenient, allowing full mid-frame releases. This is to accommodate the use of mid-frame modal native
  windows calls, which leads backends such as GLFW to send key clearing events on focus loss. (#3575)
- Style: Changed default style.WindowRounding value to 0.0f (matches default for multi-viewports).
- Style: Reduced the size of the resizing grip, made alpha less prominent.
- Style: Classic: Increase the default alpha value of WindowBg to be closer to other styles.
- Demo: Clarify usage of right-aligned items in Demo>Layout>Widgets Width.
- Backends: OpenGL3: Use glGetString(GL_VERSION) query instead of glGetIntegerv(GL_MAJOR_VERSION, ...)
  when the later returns zero (e.g. Desktop GL 2.x). (#3530) [@xndcn]
- Backends: OpenGL2: Backup and restore GL_SHADE_MODEL and disable GL_NORMAL_ARRAY state to increase
  compatibility with legacy code. (#3671)
- Backends: OpenGL3: Backup and restore GL_PRIMITIVE_RESTART state. (#3544) [@Xipiryon]
- Backends: OpenGL2, OpenGL3: Backup and restore GL_STENCIL_TEST enable state. (#3668)
- Backends: Vulkan: Added support for specifying which sub-pass to reference during VkPipeline creation. (@3579) [@bdero]
- Backends: DX12: Improve Windows 7 compatibility (for D3D12On7) by loading d3d12.dll dynamically. (#3696) [@Mattiwatti]
- Backends: Win32: Fix setting of io.DisplaySize to invalid/uninitialized data after hwnd has been closed.
- Backends: OSX: Fix keypad-enter key not working on MacOS. (#3554) [@rokups, @lfnoise]
- Examples: Apple+Metal: Consolidated/simplified to get closer to other examples. (#3543) [@warrenm]
- Examples: Apple+Metal: Forward events down so OS key combination like Cmd+Q can work. (#3554) [@rokups]
- Examples: Emscripten: Renamed example_emscripten/ to example_emscripten_opengl3/. (#3632)
- Examples: Emscripten: Added 'make serve' helper to spawn a web-server on localhost. (#3705) [@Horki]
- Examples: DirectX12: Move ImGui::Render() call above the first barrier to clarify its lack of effect on the graphics pipe.
- CI: Fix testing for Windows DLL builds. (#3603, #3601) [@iboB]
- Docs: Improved the wiki and added a https://github.com/ocornut/imgui/wiki/Useful-Widgets page. [@Xipiryon]
  [2021/05/20: moved to https://github.com/ocornut/imgui/wiki/Useful-Extensions]
- Docs: Split examples/README.txt into docs/BACKENDS.md and docs/EXAMPLES.md, and improved them.
- Docs: Consistently renamed all occurrences of "binding" and "back-end" to "backend" in comments and docs.

Docking+Viewports Branch:

- Docking: Docked windows honor change of tab and text colors. (#2771)
- Docking: Support for appending into existing tab-bar made to work with Docking + internal helper DockNodeBeginAmendTabBar().
- Docking: Added experimental TabItemFlagsOverrideSet to ImGuiWindowClass.
- Viewports: Fixed incorrect whitening of popups above a modal if both use their own viewport.
- Viewports: Backends: Vulkan: Fixed build, removed extraneous pipeline creation. (#3459, #3579)


-----------------------------------------------------------------------
 VERSION 1.79 (Released 2020-10-08)
-----------------------------------------------------------------------

Decorated log: https://github.com/ocornut/imgui/releases/tag/v1.79

Breaking Changes:

- Fonts: Removed ImFont::DisplayOffset in favor of ImFontConfig::GlyphOffset. DisplayOffset was applied
  after scaling and not very meaningful/useful outside of being needed by the default ProggyClean font.
  It was also getting in the way of better font scaling, so let's get rid of it now!
  If you used DisplayOffset it was probably in association to rasterizing a font at a specific size,
  in which case the corresponding offset may be reported into GlyphOffset. (#1619)
  If you scaled this value after calling AddFontDefault(), this is now done automatically.
- ImGuiListClipper: Renamed constructor parameters which created an ambiguous alternative to using
  the ImGuiListClipper::Begin() function, with misleading edge cases. Always use ImGuiListClipper::Begin()!
  Kept inline redirection function (will obsolete).
  (note: imgui_memory_editor <0.40 from imgui_club/ used this old clipper API. Update your copy if needed).
- Style: Renamed style.TabMinWidthForUnselectedCloseButton to style.TabMinWidthForCloseButton.
- Renamed ImGuiSliderFlags_ClampOnInput to ImGuiSliderFlags_AlwaysClamp. Kept redirection enum (will obsolete).
- Renamed OpenPopupContextItem() back to OpenPopupOnItemClick(), REVERTED CHANGE FROM 1.77.
  For variety of reason this is more self-explanatory and less error-prone. Kept inline redirection function.
- Removed return value from OpenPopupOnItemClick() - returned true on mouse release on an item - because it
  is inconsistent with other popups API and makes others misleading. It's also and unnecessary: you can
  use IsWindowAppearing() after BeginPopup() for a similar result.

Other Changes:

- Window: Fixed using non-zero pivot in SetNextWindowPos() when the window is collapsed. (#3433)
- Nav: Fixed navigation resuming on first visible item when using gamepad. [@rokups]
- Nav: Fixed using Alt to toggle the Menu layer when inside a Modal window. (#787)
- Scrolling: Fixed SetScrollHere(0) functions edge snapping when called during a frame where
  ContentSize is changing (issue introduced in 1.78). (#3452).
- InputText: Added support for Page Up/Down in InputTextMultiline(). (#3430) [@Xipiryon]
- InputText: Added selection helpers in ImGuiInputTextCallbackData().
- InputText: Added ImGuiInputTextFlags_CallbackEdit to modify internally owned buffer after an edit.
  (note that InputText() already returns true on edit, the callback is useful mainly to manipulate the
  underlying buffer while focus is active).
- InputText: Fixed using ImGuiInputTextFlags_Password with InputTextMultiline(). (#3427, #3428)
  It is a rather unusual or useless combination of features but no reason it shouldn't work!
- InputText: Fixed minor scrolling glitch when erasing trailing lines in InputTextMultiline().
- InputText: Fixed cursor being partially covered after using Ctrl+End key.
- InputText: Fixed callback's helper DeleteChars() function when cursor is inside the deleted block. (#3454)
- InputText: Made pressing Down arrow on the last line when it doesn't have a carriage return not move to
  the end of the line (so it is consistent with Up arrow, and behave same as Notepad and Visual Studio.
  Note that some other text editors instead would move the cursor to the end of the line). [@Xipiryon]
- DragFloat, DragScalar: Fixed ImGuiSliderFlags_ClampOnInput not being honored in the special case
  where v_min == v_max. (#3361)
- SliderInt, SliderScalar: Fixed reaching of maximum value with inverted integer min/max ranges, both
  with signed and unsigned types. Added reverse Sliders to Demo. (#3432, #3449) [@rokups]
- Text: Bypass unnecessary formatting when using the TextColored()/TextWrapped()/TextDisabled() helpers
  with a "%s" format string. (#3466)
- CheckboxFlags: Display mixed-value/tristate marker when passed flags that have multiple bits set and
  stored value matches neither zero neither the full set.
- BeginMenuBar: Fixed minor bug where CursorPosMax gets pushed to CursorPos prior to calling BeginMenuBar(),
  so e.g. calling the function at the end of a window would often add +ItemSpacing.y to scrolling range.
- TreeNode, CollapsingHeader: Made clicking on arrow toggle toggle the open state on the Mouse Down event
  rather than the Mouse Down+Up sequence, even if the _OpenOnArrow flag isn't set. This is standard behavior
  and amends the change done in 1.76 which only affected cases were _OpenOnArrow flag was set.
  (This is also necessary to support full multi/range-select/drag and drop operations.)
- Tab Bar: Added TabItemButton() to submit tab that behave like a button. (#3291) [@Xipiryon]
- Tab Bar: Added ImGuiTabItemFlags_Leading and ImGuiTabItemFlags_Trailing flags to position tabs or button
  at either end of the tab bar. Those tabs won't be part of the scrolling region, and when reordering cannot
  be moving outside of their section. Most often used with TabItemButton(). (#3291) [@Xipiryon]
- Tab Bar: Added ImGuiTabItemFlags_NoReorder flag to disable reordering a given tab.
- Tab Bar: Keep tab item close button visible while dragging a tab (independent of hovering state).
- Tab Bar: Fixed a small bug where closing a tab that is not selected would leave a tab hole for a frame.
- Tab Bar: Fixed a small bug where scrolling buttons (with ImGuiTabBarFlags_FittingPolicyScroll) would
  generate an unnecessary extra draw call.
- Tab Bar: Fixed a small bug where toggling a tab bar from Reorderable to not Reorderable would leave
  tabs reordered in the tab list popup. [@Xipiryon]
- Columns: Fix inverted ClipRect being passed to renderer when using certain primitives inside of
  a fully clipped column. (#3475) [@szreder]
- Popups, Tooltips: Fix edge cases issues with positioning popups and tooltips when they are larger than
  viewport on either or both axises. [@Rokups]
- Fonts: AddFontDefault() adjust its vertical offset based on floor(size/13) instead of always +1.
  Was previously done by altering DisplayOffset.y but wouldn't work for DPI scaled font.
- Metrics: Various tweaks, listing windows front-to-back, greying inactive items when possible.
- Demo: Add simple InputText() callbacks demo (aside from the more elaborate ones in 'Examples->Console').
- Backends: OpenGL3: Fix to avoid compiling/calling glBindSampler() on ES or pre 3.3 contexts which have
  the defines set by a loader. (#3467, #1985) [@jjwebb]
- Backends: Vulkan: Some internal refactor aimed at allowing multi-viewport feature to create their
  own render pass. (#3455, #3459) [@FunMiles]
- Backends: DX12: Clarified that imgui_impl_dx12 can be compiled on 32-bit systems by redefining
  the ImTextureID to be 64-bit (e.g. '#define ImTextureID ImU64' in imconfig.h). (#301)
- Backends: DX12: Fix debug layer warning when scissor rect is zero-sized. (#3472, #3462) [@StoneWolf]
- Examples: Vulkan: Reworked buffer resize handling, fix for Linux/X11. (#3390, #2626) [@RoryO]
- Examples: Vulkan: Switch validation layer to use "VK_LAYER_KHRONOS_validation" instead of
  "VK_LAYER_LUNARG_standard_validation" which is deprecated (#3459) [@FunMiles]
- Examples: DX12: Enable breaking on any warning/error when debug interface is enabled.
- Examples: DX12: Added '#define ImTextureID ImU64' in project and build files to also allow building
  on 32-bit systems. Added project to default Visual Studio solution file. (#301)

Docking+Viewports Branch:

- Docking: DockSpace() emits ItemSize() properly (useful when not filling all space).
- Docking: Fixed docking while hovering a child window. (#3420) broken by 85a661d. Improve metrics debugging.
- Docking: Fix honoring payload filter with overlapping nodes (we incorrectly over-relied on g.HoveredDockNode
  when making change for #3398).
- Docking: Fix handling of WindowMenuButtonPosition == ImGuiDir_None in Docking Nodes. (#3499)
- Viewports: Fixed a rare edge-case if the window targeted by CTRL+Tab stops being rendered.
- Viewports, Backends: DX12: Make secondary viewport format match main viewport one (#3462) {@BeastLe9enD]
- Viewports: Backends: Vulkan: Removed unused shader code. Fix leaks. Avoid unnecessary pipeline creation for main
  viewport. (#3459) + Add ImGui_ImplVulkanH_CreateWindowSwapChain in ImGui_ImplVulkanH_CreateOrResizeWindow().
- Viewports: Backends: DirectX9: Recover from D3DERR_DEVICELOST on secondary viewports. (#3424)
- Viewports, Backends: Win32: Fix toggling of ImGuiViewportFlags_TopMost (#3477) [@Kodokuna]
- Viewports: Backends: GLFW: Workaround for cases where glfwGetMonitorWorkarea fails (#3457) [@dougbinks]


-----------------------------------------------------------------------
 VERSION 1.78 (Released 2020-08-18)
-----------------------------------------------------------------------

Decorated log: https://github.com/ocornut/imgui/releases/tag/v1.78

Breaking Changes:

- Obsoleted use of the trailing 'float power=1.0f' parameter for those functions: [@Shironekoben, @ocornut]
  - DragFloat(), DragFloat2(), DragFloat3(), DragFloat4(), DragFloatRange2(), DragScalar(), DragScalarN()
  - SliderFloat(), SliderFloat2(), SliderFloat3(), SliderFloat4(), SliderScalar(), SliderScalarN()
  - VSliderFloat(), VSliderScalar()
  Replaced the final 'float power=1.0f' argument with ImGuiSliderFlags defaulting to 0 (as with all our flags).
  Worked out a backward-compatibility scheme so hopefully most C++ codebase should not be affected.
  In short, when calling those functions:
  - If you omitted the 'power' parameter (likely!), you are not affected.
  - If you set the 'power' parameter to 1.0f (same as previous default value):
    - Your compiler may warn on float>int conversion.
    - Everything else will work (but will assert if IMGUI_DISABLE_OBSOLETE_FUNCTIONS is defined).
    - You can replace the 1.0f value with 0 to fix the warning, and be technically correct.
  - If you set the 'power' parameter to >1.0f (to enable non-linear editing):
    - Your compiler may warn on float>int conversion.
    - Code will assert at runtime for IM_ASSERT(power == 1.0f) with the following assert description:
      "Call Drag function with ImGuiSliderFlags_Logarithmic instead of using the old 'float power' function!".
    - In case asserts are disabled, the code will not crash and enable the _Logarithmic flag.
    - You can replace the >1.0f value with ImGuiSliderFlags_Logarithmic to fix the warning/assert
      and get a _similar_ effect as previous uses of power >1.0f.
  See https://github.com/ocornut/imgui/issues/3361 for all details.
  For shared code, you can version check at compile-time with `#if IMGUI_VERSION_NUM >= 17704`.
  Kept inline redirection functions (will obsolete) apart for: DragFloatRange2(), VSliderFloat(), VSliderScalar().
  For those three the 'float power=1.0f' version was removed directly as they were most unlikely ever used.
- DragInt, DragFloat, DragScalar: Obsoleted use of v_min > v_max to lock edits (introduced in 1.73, this was not
  demoed nor documented much, will be replaced a more generic ReadOnly feature).

Other Changes:

- Nav: Fixed clicking on void (behind any windows) from not clearing the focused window.
  This would be problematic e.g. in situation where the application relies on io.WantCaptureKeyboard
  flag being cleared accordingly. (bug introduced in 1.77 WIP on 2020/06/16) (#3344, #2880)
- Window: Fixed clicking over an item which hovering has been disabled (e.g inhibited by a popup)
  from marking the window as moved.
- Drag, Slider: Added ImGuiSliderFlags parameters.
  - For float functions they replace the old trailing 'float power=1.0' parameter.
    (See #3361 and the "Breaking Changes" block above for all details).
  - Added ImGuiSliderFlags_Logarithmic flag to enable logarithmic editing
    (generally more precision around zero), as a replacement to the old 'float power' parameter
    which was obsoleted. (#1823, #1316, #642) [@Shironekoben, @AndrewBelt]
  - Added ImGuiSliderFlags_ClampOnInput flag to force clamping value when using
    CTRL+Click to type in a value manually. (#1829, #3209, #946, #413).
    [note: RENAMED to ImGuiSliderFlags_AlwaysClamp in 1.79].
  - Added ImGuiSliderFlags_NoRoundToFormat flag to disable rounding underlying
    value to match precision of the display format string. (#642)
  - Added ImGuiSliderFlags_NoInput flag to disable turning widget into a text input
    with CTRL+Click or Nav Enter.
- Nav, Slider: Fix using keyboard/gamepad controls with certain logarithmic sliders where
  pushing a direction near zero values would be cancelled out. [@Shironekoben]
- DragFloatRange2, DragIntRange2: Fixed an issue allowing to drag out of bounds when both
  min and max value are on the same value. (#1441)
- InputText, ImDrawList: Fixed assert triggering when drawing single line of text with more
  than ~16 KB characters. (Note that current code is going to show corrupted display if after
  clipping, more than 16 KB characters are visible in the same low-level ImDrawList::RenderText()
  call. ImGui-level functions such as TextUnformatted() are not affected. This is quite rare
  but it will be addressed later). (#3349)
- Selectable: Fixed highlight/hit extent when used with horizontal scrolling (in or outside columns).
  Also fixed related text clipping when used in a column after the first one. (#3187, #3386)
- Scrolling: Avoid SetScroll, SetScrollFromPos functions from snapping on the edge of scroll
  limits when close-enough by (WindowPadding - ItemPadding), which was a tweak with too many
  side-effects. The behavior is still present in SetScrollHere functions as they are more explicitly
  aiming at making widgets visible. May later be moved to a flag.
- Tab Bar: Allow calling SetTabItemClosed() after a tab has been submitted (will process next frame).
- InvisibleButton: Made public a small selection of ImGuiButtonFlags (previously in imgui_internal.h)
  and allowed to pass them to InvisibleButton(): ImGuiButtonFlags_MouseButtonLeft/Right/Middle.
  This is a small but rather important change because lots of multi-button behaviors could previously
  only be achieved using lower-level/internal API. Now also available via high-level InvisibleButton()
  with is a de-facto versatile building block to creating custom widgets with the public API.
- Fonts: Fixed ImFontConfig::GlyphExtraSpacing and ImFontConfig::PixelSnapH settings being pulled
  from the merged/target font settings when merging fonts, instead of being pulled from the source
  font settings.
- ImDrawList: Thick anti-aliased strokes (> 1.0f) with integer thickness now use a texture-based
  path, reducing the amount of vertices/indices and CPU/GPU usage. (#3245) [@Shironekoben]
  - This change will facilitate the wider use of thick borders in future style changes.
  - Requires an extra bit of texture space (~64x64 by default), relies on GPU bilinear filtering.
  - Set `io.AntiAliasedLinesUseTex = false` to disable rendering using this method.
  - Clear `ImFontAtlasFlags_NoBakedLines` in ImFontAtlas::Flags to disable baking data in texture.
- ImDrawList: changed AddCircle(), AddCircleFilled() default num_segments from 12 to 0, effectively
  enabling auto-tessellation by default. Tweak tessellation in Style Editor->Rendering section, or
  by modifying the 'style.CircleSegmentMaxError' value. [@ShironekoBen]
- ImDrawList: Fixed minor bug introduced in 1.75 where AddCircle() with 12 segments would generate
  an extra vertex. (This bug was mistakenly marked as fixed in earlier 1.77 release). [@ShironekoBen]
- Demo: Improved "Custom Rendering"->"Canvas" demo with a grid, scrolling and context menu.
  Also showcase using InvisibleButton() with multiple mouse buttons flags.
- Demo: Improved "Layout & Scrolling" -> "Clipping" section.
- Demo: Improved "Layout & Scrolling" -> "Child Windows" section.
- Style Editor: Added preview of circle auto-tessellation when editing the corresponding value.
- Backends: OpenGL3: Added support for glad2 loader. (#3330) [@moritz-h]
- Backends: Allegro 5: Fixed horizontal scrolling direction with mouse wheel / touch pads (it seems
  like Allegro 5 reports it differently from GLFW and SDL). (#3394, #2424, #1463) [@nobody-special666]
- Examples: Vulkan: Fixed GLFW+Vulkan and SDL+Vulkan clear color not being set. (#3390) [@RoryO]
- CI: Emscripten has stopped their support for their fastcomp backend, switching to latest sdk [@Xipiryon]

Docking+Viewports Branch:

- Docking: Made DockBuilderAddNode() automatically call DockBuilderRemoveNode(). (#3399, #2109)
- Docking: Storing HoveredDockNode in context which can be useful for easily detecting e.g. hovering an
  empty node. (#3398)
- Docking: Fixed docking overlay bits appearing at (0,0), because of 43bd80a. Most typically noticeable
  when disabling multi-viewport.
- Docking: Workaround recovery for node created without the _DockSpace flags later becoming a DockSpace. (#3340)
- Docking: Rework size allocations to recover when there's no enough room for nodes + do not hold on
  _WantLockSizeOnce forever. (#3328)
- Docking: Rework size allocation to allow user code to override node sizes. Not all edge cases will be
  properly handled but this is a step toward toolbar emitting size constraints.
- Docking: Added experimental flags to perform more docking filtering and disable resize per axis.
  Designed for toolbar patterns.
- Viewports, Backends, GLFW: Use GLFW_MOUSE_PASSTHROUGH when available.
- Viewports, Backends: DX12: Fixed issue on shutdown when viewports are disabled. (#3347)


-----------------------------------------------------------------------
 VERSION 1.77 (Released 2020-06-29)
-----------------------------------------------------------------------

Decorated log: https://github.com/ocornut/imgui/releases/tag/v1.77

Breaking Changes:

- Removed unnecessary ID (first arg) of ImFontAtlas::AddCustomRectRegular() function. Please
  note that this is a Beta api and will likely be reworked in order to support multi-DPI across
  multiple monitors.
- Renamed OpenPopupOnItemClick() to OpenPopupContextItem(). Kept inline redirection function (will obsolete).
  [NOTE: THIS WAS REVERTED IN 1.79]
- Removed BeginPopupContextWindow(const char*, int mouse_button, bool also_over_items) in favor
  of BeginPopupContextWindow(const char*, ImGuiPopupFlags flags) with ImGuiPopupFlags_NoOverItems.
  Kept inline redirection function (will obsolete).
- Removed obsoleted CalcItemRectClosestPoint() entry point (has been asserting since December 2017).

Other Changes:

- TreeNode: Fixed bug where BeginDragDropSource() failed when the _OpenOnDoubleClick flag is
  enabled (bug introduced in 1.76, but pre-1.76 it would also fail unless the _OpenOnArrow
  flag was also set, and _OpenOnArrow is frequently set along with _OpenOnDoubleClick).
- TreeNode: Fixed bug where dragging a payload over a TreeNode() with either _OpenOnDoubleClick
  or _OpenOnArrow would open the node. (#143)
- Windows: Fix unintended feedback loops when resizing windows close to main viewport edges. [@rokups]
- Tabs: Added style.TabMinWidthForUnselectedCloseButton settings:
  - Set to 0.0f (default) to always make a close button appear on hover (same as Chrome, VS).
  - Set to FLT_MAX to only display a close button when selected (merely hovering is not enough).
  - Set to an intermediary value to toggle behavior based on width (same as Firefox).
- Tabs: Added a ImGuiTabItemFlags_NoTooltip flag to disable the tooltip for individual tab item
  (vs ImGuiTabBarFlags_NoTooltip for entire tab bar). [@Xipiryon]
- Popups: All functions capable of opening popups (OpenPopup*, BeginPopupContext*) now take a new
  ImGuiPopupFlags sets of flags instead of a mouse button index. The API is automatically backward
  compatible as ImGuiPopupFlags is guaranteed to hold mouse button index in the lower bits.
- Popups: Added ImGuiPopupFlags_NoOpenOverExistingPopup for OpenPopup*/BeginPopupContext* functions
  to first test for the presence of another popup at the same level.
- Popups: Added ImGuiPopupFlags_NoOpenOverItems for BeginPopupContextWindow() - similar to testing
  for !IsAnyItemHovered() prior to doing an OpenPopup().
- Popups: Added ImGuiPopupFlags_AnyPopupId and ImGuiPopupFlags_AnyPopupLevel flags for IsPopupOpen(),
  allowing to check if any popup is open at the current level, if a given popup is open at any popup
  level, if any popup is open at all.
- Popups: Fix an edge case where programmatically closing a popup while clicking on its empty space
  would attempt to focus it and close other popups. (#2880)
- Popups: Fix BeginPopupContextVoid() when clicking over the area made unavailable by a modal. (#1636)
- Popups: Clarified some of the comments and function prototypes.
- Modals: BeginPopupModal() doesn't set the ImGuiWindowFlags_NoSavedSettings flag anymore, and will
  not always be auto-centered. Note that modals are more similar to regular windows than they are to
  popups, so api and behavior may evolve further toward embracing this. (#915, #3091)
  Enforce centering using e.g. SetNextWindowPos(io.DisplaySize * 0.5f, ImGuiCond_Appearing, ImVec2(0.5f,0.5f)).
- Metrics: Added a "Settings" section with some details about persistent ini settings.
- Nav, Menus: Fix vertical wrap-around in menus or popups created with multiple appending calls to
  BeginMenu()/EndMenu() or BeginPopup(0/EndPopup(). (#3223, #1207) [@rokups]
- Drag and Drop: Fixed unintended fallback "..." tooltip display during drag operation when
  drag source uses _SourceNoPreviewTooltip flags. (#3160) [@rokups]
- Columns: Lower overhead on column switches and switching to background channel.
  Benefits Columns but was primarily made with Tables in mind!
- Fonts: Fix GetGlyphRangesKorean() end-range to end at 0xD7A3 (instead of 0xD79D). (#348, #3217) [@marukrap]
- ImDrawList: Fixed an issue where draw command merging or primitive unreserve while crossing the
  VtxOffset boundary would lead to draw commands with wrong VtxOffset. (#3129, #3163, #3232, #2591)
  [@thedmd, @Shironekoben, @sergeyn, @ocornut]
- ImDrawList, ImDrawListSplitter, Columns: Fixed an issue where changing channels with different
  TextureId, VtxOffset would incorrectly apply new settings to draw channels. (#3129, #3163)
  [@ocornut, @thedmd, @Shironekoben]
- ImDrawList, ImDrawListSplitter, Columns: Fixed an issue where starting a split when current
  VtxOffset was not zero would lead to draw commands with wrong VtxOffset. (#2591)
- ImDrawList, ImDrawListSplitter, Columns: Fixed an issue where starting a split right after
  a callback draw command would incorrectly override the callback draw command.
- Misc, Freetype: Fix for rare case where FT_Get_Char_Index() succeeds but FT_Load_Glyph() fails.
- Docs: Improved and moved font documentation to docs/FONTS.md so it can be readable on the web.
  Updated various links/wiki accordingly. Added FAQ entry about DPI. (#2861) [@ButternCream, @ocornut]
- CI: Added CI test to verify we're never accidentally dragging libstdc++ (on some compiler setups,
  static constructors for non-pod data seems to drag in libstdc++ due to thread-safety concerns).
  Fixed a static constructor which led to this dependency on some compiler setups. [@rokups]
- Backends: Win32: Support for #define NOGDI, won't try to call GetDeviceCaps(). (#3137, #2327)
- Backends: Win32: Fix _WIN32_WINNT < 0x0600 (MinGW defaults to 0x502 == Windows 2003). (#3183)
- Backends: SDL: Report a zero display-size when window is minimized, consistent with other backends,
  making more render/clipping code use an early out path.
- Backends: OpenGL: Fixed handling of GL 4.5+ glClipControl(GL_UPPER_LEFT) by inverting the
  projection matrix top and bottom values. (#3143, #3146) [@u3shit]
- Backends: OpenGL: On OSX, if unspecified by app, made default GLSL version 150. (#3199) [@albertvaka]
- Backends: OpenGL: Fixed loader auto-detection to not interfere with ES2/ES3 defines. (#3246) [@funchal]
- Backends: Vulkan: Fixed error in if initial frame has no vertices. (#3177)
- Backends: Vulkan: Fixed edge case where render callbacks wouldn't be called if the ImDrawData
  structure didn't have any vertices. (#2697) [@kudaba]
- Backends: OSX: Added workaround to avoid fast mouse clicks. (#3261, #1992, #2525) [@nburrus]
- Examples: GLFW+Vulkan, SDL+Vulkan: Fix for handling of minimized windows. (#3259)
- Examples: Apple: Fixed example_apple_metal and example_apple_opengl2 using imgui_impl_osx.mm
  not forwarding right and center mouse clicks. (#3260) [@nburrus]

Docking+Viewports Branch:

- Viewports: Don't set ImGuiViewportFlags_NoRendererClear when ImGuiWindowFlags_NoBackground is set. (#3213)
- Viewports: Report minimized viewports as zero DisplaySize to be consistent with main branch. (#1542)
- Docking, Settings: Allow reload of settings data at runtime. (#2573)
- Backends, GLFW: Fix windows resizing incorrectly on Linux due to GLFW firing window positioning
  callbacks on next frame after window is resized manually. (#2117)
- Backends: DX12: Fix OBJECT_DELETED_WHILE_STILL_IN_USE on viewport resizing. (#3210)
- Backends: DX12: Fix for crash caused by early resource release. (#3121)
- Backends, Win32: Request monitor update when DPI awareness is enabled to make sure they have the correct DPI settings.


-----------------------------------------------------------------------
 VERSION 1.76 (Released 2020-04-12)
-----------------------------------------------------------------------

Decorated log: https://github.com/ocornut/imgui/releases/tag/v1.76

Other Changes:

- Drag and Drop, Nav: Disabling navigation arrow keys when drag and drop is active. In the docking
  branch pressing arrow keys while dragging a window from a tab could trigger an assert. (#3025)
- BeginMenu: Using same ID multiple times appends content to a menu. (#1207) [@rokups]
- BeginMenu: Fixed a bug where SetNextWindowXXX data before a BeginMenu() would not be cleared
  when the menu is not open. (#3030)
- InputText: Fixed password fields displaying ASCII spaces as blanks instead of using the '*'
  glyph. (#2149, #515)
- Selectable: Fixed honoring style.SelectableTextAlign with unspecified size. (#2347, #2601)
- Selectable: Allow using ImGuiSelectableFlags_SpanAllColumns in other columns than first. (#125)
- TreeNode: Made clicking on arrow with _OpenOnArrow toggle the open state on the Mouse Down
  event rather than the Mouse Down+Up sequence (this is rather standard behavior).
- ColorButton: Added ImGuiColorEditFlags_NoBorder flag to remove the border normally enforced
  by default for standalone ColorButton.
- Nav: Fixed interactions with ImGuiListClipper, so e.g. Home/End result would not clip the
  landing item on the landing frame. (#787)
- Nav: Fixed currently focused item from ever being clipped by ItemAdd(). (#787)
- Scrolling: Fixed scrolling centering API leading to non-integer scrolling values and initial
  cursor position. This would often get fixed after the fix item submission, but using the
  ImGuiListClipper as the first thing after Begin() could largely break size calculations. (#3073)
- Added optional support for Unicode plane 1-16 (#2538, #2541, #2815) [@cloudwu, @samhocevar]
  - Compile-time enable with '#define IMGUI_USE_WCHAR32' in imconfig.h.
  - More onsistent handling of unsupported code points (0xFFFD).
  - Surrogate pairs are supported when submitting UTF-16 data via io.AddInputCharacterUTF16(),
    allowing for more complete CJK input.
  - sizeof(ImWchar) goes from 2 to 4. IM_UNICODE_CODEPOINT_MAX goes from 0xFFFF to 0x10FFFF.
  - Various structures such as ImFont, ImFontGlyphRangesBuilder will use more memory, this
    is currently not particularly efficient.
- Columns: undid the change in 1.75 were Columns()/BeginColumns() were preemptively limited
  to 64 columns with an assert. (#3037, #125)
- Window: Fixed a bug with child window inheriting ItemFlags from their parent when the child
  window also manipulate the ItemFlags stack. (#3024) [@Stanbroek]
- Font: Fixed non-ASCII space occasionally creating unnecessary empty looking polygons.
- Misc: Added an explicit compile-time test for non-scoped IM_ASSERT() macros to redirect users
  to a solution rather than encourage people to add braces in the codebase.
- Misc: Added additional checks in EndFrame() to verify that io.KeyXXX values have not been
  tampered with between NewFrame() and EndFrame().
- Misc: Made default clipboard handlers for Win32 and OSX use a buffer inside the main context
  instead of a static buffer, so it can be freed properly on Shutdown. (#3110)
- Misc, Freetype: Fixed support for IMGUI_STB_RECT_PACK_FILENAME compile time directive
  in imgui_freetype.cpp (matching support in the regular code path). (#3062) [@DonKult]
- Metrics: Made Tools section more prominent. Showing wire-frame mesh directly hovering the ImDrawCmd
  instead of requiring to open it. Added options to disable bounding box and mesh display.
  Added notes on inactive/gc-ed windows.
- Demo: Added black and white and color gradients to Demo>Examples>Custom Rendering.
- CI: Added more tests on the continuous-integration server: extra warnings for Clang/GCC, building
  SDL+Metal example, building imgui_freetype.cpp, more compile-time imconfig.h settings: disabling
  obsolete functions, enabling 32-bit ImDrawIdx, enabling 32-bit ImWchar, disabling demo. [@rokups]
- Backends: OpenGL3: Fixed version check mistakenly testing for GL 4.0+ instead of 3.2+ to enable
  ImGuiBackendFlags_RendererHasVtxOffset, leaving 3.2 contexts without it. (#3119, #2866) [@wolfpld]
- Backends: OpenGL3: Added include support for older glbinding 2.x loader. (#3061) [@DonKult]
- Backends: Win32: Added ImGui_ImplWin32_EnableDpiAwareness(), ImGui_ImplWin32_GetDpiScaleForHwnd(),
  ImGui_ImplWin32_GetDpiScaleForMonitor() helpers functions (backported from the docking branch).
  Those functions makes it easier for example apps to support hi-dpi features without setting up
  a manifest.
- Backends: Win32: Calling AddInputCharacterUTF16() from WM_CHAR message handler in order to support
  high-plane surrogate pairs. (#2815) [@cloudwu, @samhocevar]
- Backends: SDL: Added ImGui_ImplSDL2_InitForMetal() for API consistency (even though the function
  currently does nothing).
- Backends: SDL: Fixed mapping for ImGuiKey_KeyPadEnter. (#3031) [@Davido71]
- Examples: Win32+DX12: Fixed resizing main window, enabled debug layer. (#3087, #3115) [@sergeyn]
- Examples: SDL+DX11: Fixed resizing main window. (#3057) [@joeslay]
- Examples: Added SDL+Metal example application. (#3017) [@coding-jackalope]

Docking+Viewports Branch:

- Docking: Fixed assert preventing dockspace from being created instead a hidden tab. (#3101)
- Viewports: Fixed secondary viewports accidentally merging into a minimized host viewport. (#3118)
- Viewports, Docking: Added per-viewport work area system for e.g. menu-bars. Fixed DockspaceOverViewport()
  and demo code (overlay etc) accordingly. (#3035, #2889, #2474, #1542, #2109)
- Viewports: Improve menu positioning in multi-monitor setups. [@rokups]
- Viewports: Software mouse cursor is also scaled by current DpiScale. (amend #939)
- Viewports: Avoid manually clipping resize grips and borders, which messes up with automation ability
  to locate those items. Also simpler and more standard.
- Viewports: Fix for UWP in the imgui_impl_win32.cpp IME handler. (#2895, #2892).
- Viewports: Bunch of extra of comments to facilitate setting up multi-viewports.
- Viewports, GLFW: Avoid using window positioning workaround for GLFW 3.3+ versions that have it fixed.


-----------------------------------------------------------------------
 VERSION 1.75 (Released 2020-02-10)
-----------------------------------------------------------------------

Decorated log: https://github.com/ocornut/imgui/releases/tag/v1.75

Breaking Changes:

- Removed redirecting functions/enums names that were marked obsolete in 1.53 (December 2017):
  - ShowTestWindow()                    -> use ShowDemoWindow()
  - IsRootWindowFocused()               -> use IsWindowFocused(ImGuiFocusedFlags_RootWindow)
  - IsRootWindowOrAnyChildFocused()     -> use IsWindowFocused(ImGuiFocusedFlags_RootAndChildWindows)
  - SetNextWindowContentWidth(w)        -> use SetNextWindowContentSize(ImVec2(w, 0.0f)
  - GetItemsLineHeightWithSpacing()     -> use GetFrameHeightWithSpacing()
  - ImGuiCol_ChildWindowBg              -> use ImGuiCol_ChildBg
  - ImGuiStyleVar_ChildWindowRounding   -> use ImGuiStyleVar_ChildRounding
  - ImGuiTreeNodeFlags_AllowOverlapMode -> use ImGuiTreeNodeFlags_AllowItemOverlap
  - IMGUI_DISABLE_TEST_WINDOWS          -> use IMGUI_DISABLE_DEMO_WINDOWS
  If you were still using the old names, while you are cleaning up, considering enabling
  IMGUI_DISABLE_OBSOLETE_FUNCTIONS in imconfig.h even temporarily to have a pass at finding
  and removing up old API calls, if any remaining.
- Removed implicit default parameter to IsMouseDragging(int button = 0) to be consistent
  with other mouse functions (none of the other functions have it).
- Obsoleted calling ImDrawList::PrimReserve() with a negative count (which was vaguely
  documented and rarely if ever used). Instead we added an explicit PrimUnreserve() API
  which can be implemented faster. Also clarified pre-existing constraints which weren't
  documented (can only unreserve from the last reserve call). If you suspect you ever
  used that feature before (very unlikely, but grep for call to PrimReserve in your code),
  you can #define IMGUI_DEBUG_PARANOID in imconfig.h to catch existing calls. [@ShironekoBen]
- ImDrawList::AddCircle()/AddCircleFilled() functions don't accept negative radius.
- Limiting Columns()/BeginColumns() api to 64 columns with an assert. While the current code
  technically supports it, future code may not so we're putting the restriction ahead.
  [Undid that change in 1.76]
- imgui_internal.h: changed ImRect() default constructor initializes all fields to 0.0f instead
  of (FLT_MAX,FLT_MAX,-FLT_MAX,-FLT_MAX). If you used ImRect::Add() to create bounding boxes by
  adding points into it without explicit initialization, you may need to fix your initial value.

Other Changes:

- Inputs: Added ImGuiMouseButton enum for convenience (e.g. ImGuiMouseButton_Right=1).
  We forever guarantee that the existing value will not changes so existing code is free to use 0/1/2.
- Nav: Fixed a bug where the initial CTRL-Tab press while in a child window sometimes selected
  the current root window instead of always selecting the previous root window. (#787)
- ColorEdit: Fix label alignment when using ImGuiColorEditFlags_NoInputs. (#2955) [@rokups]
- ColorEdit: In HSV display of a RGB stored value, attempt to locally preserve Saturation
  when Value==0.0 (similar to changes done in 1.73 for Hue). Removed Hue editing lock since
  those improvements in 1.73 makes them unnecessary. (#2722, #2770). [@rokups]
- ColorEdit: "Copy As" context-menu tool shows hex values with a '#' prefix instead of '0x'.
- ColorEdit: "Copy As" content-menu tool shows hex values both with/without alpha when available.
- InputText: Fix corruption or crash when executing undo after clearing input with ESC, as a
  byproduct we are allowing to later undo the revert with a CTRL+Z. (#3008).
- InputText: Fix using a combination of _CallbackResize (e.g. for std::string binding), along with the
  _EnterReturnsTrue flag along with the rarely used property of using an InputText without persisting
  user-side storage. Previously if you had e.g. a local unsaved std::string and reading result back
  from the widget, the user string object wouldn't be resized when Enter key was pressed. (#3009)
- MenuBar: Fix minor clipping issue where occasionally a menu text can overlap the right-most border.
- Window: Fix SetNextWindowBgAlpha(1.0f) failing to override alpha component. (#3007) [@Albog]
- Window: When testing for the presence of the ImGuiWindowFlags_NoBringToFrontOnFocus flag we
  test both the focused/clicked window (which could be a child window) and the root window.
- ImDrawList: AddCircle(), AddCircleFilled() API can now auto-tessellate when provided a segment
  count of zero. Alter tessellation quality with 'style.CircleSegmentMaxError'. [@ShironekoBen]
- ImDrawList: Add AddNgon(), AddNgonFilled() API with a guarantee on the explicit segment count.
  In the current branch they are essentially the same as AddCircle(), AddCircleFilled() but as
  we will rework the circle rendering functions to use textures and automatic segment count
  selection, those new api can fill a gap. [@ShironekoBen]
- Columns: ImDrawList::Channels* functions now work inside columns. Added extra comments to
  suggest using user-owned ImDrawListSplitter instead of ImDrawList functions. [@rokups]
- Misc: Added ImGuiMouseCursor_NotAllowed enum so it can be used by more shared widgets. [@rokups]
- Misc: Added IMGUI_DISABLE compile-time definition to make all headers and sources empty.
- Misc: Disable format checks when using stb_printf, to allow using extra formats.
  Made IMGUI_USE_STB_SPRINTF a properly documented imconfig.h flag. (#2954) [@loicmolinari]
- Misc: Added misc/single_file/imgui_single_file.h, We use this to validate compiling all *.cpp
  files in a same compilation unit. Actual users of that technique (also called "Unity builds")
  can generally provide this themselves, so we don't really recommend you use this. [@rokups]
- CI: Added PVS-Studio static analysis on the continuous-integration server. [@rokups]
- Backends: GLFW, SDL, Win32, OSX, Allegro: Added support for ImGuiMouseCursor_NotAllowed. [@rokups]
- Backends: GLFW: Added support for the missing mouse cursors newly added in GLFW 3.4+. [@rokups]
- Backends: SDL: Wayland: use SDL_GetMouseState (because there is no global mouse state available
  on Wayland). (#2800, #2802) [@NeroBurner]
- Backends: GLFW, SDL: report Windows key (io.KeySuper) as always released. Neither GLFW nor SDL can
  correctly report the key release in every cases (e.g. when using Win+V) causing problems with some
  widgets. The next release of GLFW (3.4+) will have a fix for it. However since it is both difficult
  and discouraged to make use of this key for Windows application anyway, we just hide it. (#2976)
- Backends: Win32: Added support for #define IMGUI_IMPL_WIN32_DISABLE_GAMEPAD to disable all
  XInput using code, and IMGUI_IMPL_WIN32_DISABLE_LINKING_XINPUT to disable linking with XInput,
  the later may be problematic if compiling with recent Windows SDK and you want your app to run
  on Windows 7. You can instead try linking with Xinput9_1_0.lib instead. (#2716)
- Backends: Glut: Improved FreeGLUT support for MinGW. (#3004) [@podsvirov]
- Backends: Emscripten: Avoid forcefully setting IMGUI_DISABLE_FILE_FUNCTIONS. (#3005) [@podsvirov]
- Examples: OpenGL: Explicitly adding -DIMGUI_IMPL_OPENGL_LOADER_GL3W to Makefile to match linking
  settings (otherwise if another loader such as Glew is accessible, the OpenGL3 backend might
  automatically use it). (#2919, #2798)
- Examples: OpenGL: Added support for glbinding OpenGL loader. (#2870) [@rokups]
- Examples: Emscripten: Demonstrating embedding fonts in Makefile and code. (#2953) [@Oipo]
- Examples: Metal: Wrapped main loop in @autoreleasepool block to ensure allocations get freed
  even if underlying system event loop gets paused due to app nap. (#2910, #2917) [@bear24rw]

Docking+Viewports Branch:

- Docking + Nav: Fixed messed up Ctrl+Tab order with docked windows.
- Docking + Nav: Fixed failing to restore NavId when refocusing a child within a docked window.
- Docking + Nav: Fixed failing to restore NavId when refocusing due to missing nav window (when
  it stops being submitted).
- Docking: Fixed a bug where the tab bar of a hidden dockspace would keep requesting focus. (#2960)
- Docking: Added experimental DockNodeFlagsOverrideSet/DockNodeFlagsOverrideClear flags in ImGuiWindowClass
  (currently experimenting with toolbar idioms).
- Viewports: Fix resizing viewport-owning windows when mouse pos is outside the InnerClipRect
  (can happen with OS decoration enabled).
- Viewports: Preserve last known size for minimized main viewport to be consistent with secondary viewports.
- Backends: SDL: Honor NoTaskBarIcon flag under non Win32 OS. (#2117)
- Backends: GLFW, SDL: Platform monitors declared properly even if multi-viewport is not enabled.


-----------------------------------------------------------------------
 VERSION 1.74 (Released 2019-11-25)
-----------------------------------------------------------------------

Decorated log: https://github.com/ocornut/imgui/releases/tag/v1.74

Breaking Changes:

- Removed redirecting functions/enums names that were marked obsolete in 1.52 (October 2017):
  - Begin() [old 5 args version]     -> use Begin() [3 args], use SetNextWindowSize() SetNextWindowBgAlpha() if needed
  - IsRootWindowOrAnyChildHovered()  -> use IsWindowHovered(ImGuiHoveredFlags_RootAndChildWindows)
  - AlignFirstTextHeightToWidgets()  -> use AlignTextToFramePadding()
  - SetNextWindowPosCenter()         -> use SetNextWindowPos() with a pivot of (0.5f, 0.5f)
  - ImFont::Glyph                    -> use ImFontGlyph
  If you were still using the old names, read "API Breaking Changes" section of imgui.cpp to find out
  the new names or equivalent features, or see how they were implemented until 1.73.
- Inputs: Fixed a miscalculation in the keyboard/mouse "typematic" repeat delay/rate calculation, used
  by keys and e.g. repeating mouse buttons as well as the GetKeyPressedAmount() function.
  If you were using a non-default value for io.KeyRepeatRate (previous default was 0.250), you can
  add +io.KeyRepeatDelay to it to compensate for the fix.
  The function was triggering on: 0.0 and (delay+rate*N) where (N>=1). Fixed formula responds to (N>=0).
  Effectively it made io.KeyRepeatRate behave like it was set to (io.KeyRepeatRate + io.KeyRepeatDelay).
  Fixed the code and altered default io.KeyRepeatRate,Delay from 0.250,0.050 to 0.300,0.050 to compensate.
  If you never altered io.KeyRepeatRate nor used GetKeyPressedAmount() this won't affect you.
- Misc: Renamed IMGUI_DISABLE_FORMAT_STRING_FUNCTIONS to IMGUI_DISABLE_DEFAULT_FORMAT_FUNCTIONS. (#1038)
- Misc: Renamed IMGUI_DISABLE_MATH_FUNCTIONS to IMGUI_DISABLE_DEFAULT_MATH_FUNCTIONS.
- Fonts: ImFontAtlas::AddCustomRectRegular() now requires an ID larger than 0x110000 (instead of 0x10000) to
  conform with supporting Unicode planes 1-16 in a future update. ID below 0x110000 will now assert.
- Backends: DX12: Added extra ID3D12DescriptorHeap parameter to ImGui_ImplDX12_Init() function.
  The value is unused in master branch but will be used by the multi-viewport feature. (#2851) [@obfuscate]

Other Changes:

- InputText, Nav: Fixed Home/End key broken when activating Keyboard Navigation. (#787)
- InputText: Filter out ASCII 127 (DEL) emitted by low-level OSX layer, as we are using the Key value. (#2578)
- Layout: Fixed a couple of subtle bounding box vertical positioning issues relating to the handling of text
  baseline alignment. The issue would generally manifest when laying out multiple items on a same line,
  with varying heights and text baseline offsets.
  Some specific examples, e.g. a button with regular frame padding followed by another item with a
  multi-line label and no frame padding, such as: multi-line text, small button, tree node item, etc.
  The second item was correctly offset to match text baseline, and would interact/display correctly,
  but it wouldn't push the contents area boundary low enough.
- Scrollbar: Fixed an issue where scrollbars wouldn't display on the frame following a frame where
  all child window contents would be culled.
- ColorPicker: Fixed SV triangle gradient to block (broken in 1.73). (#2864, #2711). [@lewa-j]
- TreeNode: Fixed combination of ImGuiTreeNodeFlags_SpanFullWidth and ImGuiTreeNodeFlags_OpenOnArrow
  incorrectly locating the arrow hit position to the left of the frame. (#2451, #2438, #1897)
- TreeNode: The collapsing arrow accepts click even if modifier keys are being held, facilitating
  interactions with custom multi-selections patterns. (#2886, #1896, #1861)
- TreeNode: Added IsItemToggledOpen() to explicitly query if item was just open/closed, facilitating
  interactions with custom multi-selections patterns. (#1896, #1861)
- DragScalar, SliderScalar, InputScalar: Added p_ prefix to parameter that are pointers to the data
  to clarify how they are used, and more comments redirecting to the demo code. (#2844)
- Error handling: Assert if user mistakenly calls End() instead of EndChild() on a child window. (#1651)
- Misc: Optimized storage of window settings data (reducing allocation count).
- Misc: Windows: Do not use _wfopen() if IMGUI_DISABLE_WIN32_FUNCTIONS is defined. (#2815)
- Misc: Windows: Disabled win32 function by default when building with UWP. (#2892, #2895)
- Misc: Using static_assert() when using C++11, instead of our own construct (avoid zealous Clang warnings).
- Misc: Added IMGUI_DISABLE_FILE_FUNCTIONS/IMGUI_DISABLE_DEFAULT_FILE_FUNCTION to nullify or disable
  default implementation of ImFileXXX functions linking with fopen/fclose/fread/fwrite. (#2734)
- Docs: Improved and moved FAQ to docs/FAQ.md so it can be readable on the web. [@ButternCream, @ocornut]
- Docs: Moved misc/fonts/README.txt to docs/FONTS.txt.
- Docs: Added permanent redirect from https://www.dearimgui.org/faq to FAQ page.
- Demo: Added simple item reordering demo in Widgets -> Drag and Drop section. (#2823, #143) [@rokups]
- Metrics: Show wire-frame mesh and approximate surface area when hovering ImDrawCmd. [@ShironekoBen]
- Metrics: Expose basic details of each window key/value state storage.
- Examples: DX12: Using IDXGIDebug1::ReportLiveObjects() when DX12_ENABLE_DEBUG_LAYER is enabled.
- Examples: Emscripten: Removed BINARYEN_TRAP_MODE=clamp from Makefile which was removed in Emscripten 1.39.0
  but required prior to 1.39.0, making life easier for absolutely no-one. (#2877, #2878) [@podsvirov]
- Backends: OpenGL2: Explicitly backup, setup and restore GL_TEXTURE_ENV to increase compatibility with
  legacy OpenGL applications. (#3000)
- Backends: OpenGL3: Fix building with pre-3.2 GL loaders which do not expose glDrawElementsBaseVertex(),
  using runtime GL version to decide if we set ImGuiBackendFlags_RendererHasVtxOffset. (#2866, #2852) [@dpilawa]
- Backends: OSX: Fix using Backspace key. (#2578, #2817, #2818) [@DiligentGraphics]
- Backends: GLFW: Previously installed user callbacks are now restored on shutdown. (#2836) [@malte-v]
- CI: Set up a bunch of continuous-integration tests using GitHub Actions. We now compile many of the example
  applications on Windows, Linux, MacOS, iOS, Emscripten. Removed Travis integration. (#2865) [@rokups]

Docking+Viewports Branch:

- Docking: Can undock from the small triangle button. (#2109,. #2645)
- Docking: Fixed node->HasCloseButton not honoring ImGuiDockNodeFlags_NoCloseButton in a floating node,
  leading to empty space at the right of tab-bars with those flags. (#2109)
- Docking: Made docked windows not use style.ChildRounding.
- Multi-viewports: Added multi-viewport support in the DX12 back-end. (#2851) [@obfuscate]


-----------------------------------------------------------------------
 VERSION 1.73 (Released 2019-09-24)
-----------------------------------------------------------------------

Decorated log: https://github.com/ocornut/imgui/releases/tag/v1.73

Other Changes:

- Nav, Scrolling: Added support for Home/End key. (#787)
- ColorEdit: Disable Hue edit when Saturation==0 instead of letting Hue values jump around.
- ColorEdit, ColorPicker: In HSV display of a RGB stored value, attempt to locally preserve Hue
  when Saturation==0, which reduces accidentally lossy interactions. (#2722, #2770) [@rokups]
- ColorPicker: Made rendering aware of global style alpha of the picker can be faded out. (#2711)
  Note that some elements won't accurately fade down with the same intensity, and the color wheel
  when enabled will have small overlap glitches with (style.Alpha < 1.0).
- TabBar: Fixed single-tab not shrinking their width down.
- TabBar: Fixed clicking on a tab larger than tab-bar width creating a bouncing feedback loop.
- TabBar: Feed desired width (sum of unclipped tabs width) into layout system to allow for auto-resize. (#2768)
  (before 1.71 tab bars fed the sum of current width which created feedback loops in certain situations).
- TabBar: Improved shrinking for large number of tabs to avoid leaving extraneous space on the right side.
  Individuals tabs are given integer-rounded width and remainder is spread between tabs left-to-right.
- Columns, Separator: Fixed a bug where non-visible separators within columns would alter the next row position
  differently than visible ones.
- SliderScalar: Improved assert when using U32 or U64 types with a large v_max value. (#2765) [@loicmouton]
- DragInt, DragFloat, DragScalar: Using (v_min > v_max) allows locking any edits to the value.
- DragScalar: Fixed dragging of unsigned values on ARM cpu (float to uint cast is undefined). (#2780) [@dBagrat]
- TreeNode: Added ImGuiTreeNodeFlags_SpanAvailWidth flag. (#2451, #2438, #1897) [@Melix19, @PathogenDavid]
  This extends the hit-box to the right-most edge, even if the node is not framed.
  (Note: this is not the default in order to allow adding other items on the same line. In the future we will
  aim toward refactoring the hit-system to be front-to-back, allowing more natural overlapping of items,
  and then we will be able to make this the default.)
- TreeNode: Added ImGuiTreeNodeFlags_SpanFullWidth flag. This extends the hit-box to both the left-most and
  right-most edge of the working area, bypassing indentation.
- CollapsingHeader: Added support for ImGuiTreeNodeFlags_Bullet and ImGuiTreeNodeFlags_Leaf on framed nodes,
  mostly for consistency. (#2159, #2160) [@goran-w]
- Selectable: Added ImGuiSelectableFlags_AllowItemOverlap flag in public api (was previously internal only).
- Style: Allow style.WindowMenuButtonPosition to be set to ImGuiDir_None to hide the collapse button. (#2634, #2639)
- Font: Better ellipsis ("...") drawing implementation. Instead of drawing three pixel-ey dots (which was glaringly
  unfitting with many types of fonts) we first attempt to find a standard ellipsis glyphs within the loaded set.
  Otherwise we render ellipsis using '.' from the font from where we trim excessive spacing to make it as narrow
  as possible. (#2775) [@rokups]
- ImDrawList: Clarified the name of many parameters so reading the code is a little easier. (#2740)
- ImDrawListSplitter: Fixed merging channels if the last submitted draw command used a different texture. (#2506)
- Using offsetof() when available in C++11. Avoids Clang sanitizer complaining about old-style macros. (#94)
- ImVector: Added find(), find_erase(), find_erase_unsorted() helpers.
- Added a mechanism to compact/free the larger allocations of unused windows (buffers are compacted when
  a window is unused for 60 seconds, as per io.ConfigWindowsMemoryCompactTimer = 60.0f). Note that memory
  usage has never been reported as a problem, so this is merely a touch of overzealous luxury. (#2636)
- Documentation: Various tweaks and improvements to the README page. [@ker0chan]
- Backends: OpenGL3: Tweaked initialization code allow application calling ImGui_ImplOpenGL3_CreateFontsTexture()
  before ImGui_ImplOpenGL3_NewFrame(), which sometimes can be convenient.
- Backends: OpenGL3: Attempt to automatically detect default GL loader by using __has_include. (#2798) [@o-micron]
- Backends: DX11: Fixed GSGetShader() call not passing an initialized instance count, which would
  generally make the DX11 debug layer complain (bug added in 1.72).
- Backends: Vulkan: Added support for specifying multisample count. Set 'ImGui_ImplVulkan_InitInfo::MSAASamples' to
   one of the VkSampleCountFlagBits values to use, default is non-multisampled as before. (#2705, #2706) [@vilya]
- Examples: OSX: Fix example_apple_opengl2/main.mm not forwarding mouse clicks and drags correctly. (#1961, #2710)
  [@intonarumori, @ElectricMagic]
- Misc: Updated stb_rect_pack.h from 0.99 to 1.00 (fixes by @rygorous: off-by-1 bug in best-fit heuristic,
  fix handling of rectangles too large to fit inside texture). (#2762) [@tido64]

Docking+Viewports Branch:

- Docking: Fix BeginDocked() path that creates node so that SetNextWindowDockID() doesn't immediately discard the node. (#2109)
- Docking: Fix for node created at the same time as windows that are still resizing (typically with
  io.ConfigDockingAlwaysTabBar) to not be zero/min sized. (#2109). The fix delays their visibility by one frame,
  which is not ideal but not very problematic as the .ini data gets populated after that.
- Docking: Fix a crash that could occur with a malformed ini file (DockNode Parent value pointing to a missing node).
- Viewport: Fix modal/popup window being stuck in unowned hidden viewport associated to fallback window without stealing
  it back. Fix modal reference viewport when opened outside of another window. (#1542)
- Viewport: Modals don't need to set ImGuiViewportFlags_NoFocusOnClick, this also mitigate the issue described by #2445,
  which becomes particularly bad with unfocused modal. (#1542)
- Viewport: better case case where host window gets moved and resized simultaneous (toggling maximized state).
  There's no perfect solution there, than using io.ConfigViewportsNoAutoMerge = false. (#1542)
- Viewport, Docking: Fixed incorrect assignment of IsFallbackWindow which would tag dock node host windows created
  in NewFrame() as such, messing with popup viewport inheritance.
- Viewport: Fixed issue where resize grip would display as hovered while mouse is still off the OS bounds so a click
  would miss it and focus the OS window behind expected one. (#1542)
- Viewport: Fix to allow multiple shutdown / calls to DestroyPlatformWindows(). (#2769)
- Viewport: Backends: GLFW: Fix setting window size on macOS (#2767, #2117) [@rokups]
- Viewport: Backends: GLFW+Linux: Fix window having incorrect size after uncollapse. (#2756, #2117) [@rokups]
- Viewport: Backends: DirectX9: Workaround for windows not refreshing when main viewport has no draw call. (#2560)


-----------------------------------------------------------------------
 VERSION 1.72b (Released 2019-07-31)
-----------------------------------------------------------------------

Decorated log: https://github.com/ocornut/imgui/releases/tag/v1.72b

Other Changes:

- Nav, Scrolling: Fixed programmatic scroll leading to a slightly incorrect scroll offset when
  the window has decorations or a menu-bar (broken in 1.71). This was mostly noticeable when
  a keyboard/gamepad movement led to scrolling the view, or using e.g. SetScrollHereY() function.
- Nav: Made hovering non-MenuItem Selectable not re-assign the source item for keyboard navigation.
- Nav: Fixed an issue with NavFlattened window flag (beta) where widgets not entirely fitting
  in child window (often selectables because of their protruding sides) would be not considered
  as entry points to to navigate toward the child window. (#787)


-----------------------------------------------------------------------
 VERSION 1.72 (Released 2019-07-27)
-----------------------------------------------------------------------

Decorated log: https://github.com/ocornut/imgui/releases/tag/v1.72

Breaking Changes:

- Removed redirecting functions/enums names that were marked obsolete in 1.51 (June 2017):
  - ImGuiCol_Column*, ImGuiSetCond_* enums.
  - IsItemHoveredRect(), IsPosHoveringAnyWindow(), IsMouseHoveringAnyWindow(), IsMouseHoveringWindow() functions.
  - IMGUI_ONCE_UPON_A_FRAME macro.
  If you were still using the old names, read "API Breaking Changes" section of imgui.cpp to find out
  the new names or equivalent features.
- Renamed ImFontAtlas::CustomRect to ImFontAtlasCustomRect. Kept redirection typedef (will obsolete).
- Removed TreeAdvanceToLabelPos() which is rarely used and only does SetCursorPosX(GetCursorPosX() + GetTreeNodeToLabelSpacing()).
  Kept redirection function (will obsolete). (#581, #324)

Other Changes:

- Scrolling: Made mouse-wheel scrolling lock the underlying window until the mouse is moved again or
  until a short delay expires (~2 seconds). This allow uninterrupted scroll even if child windows are
  passing under the mouse cursor. (#2604)
- Scrolling: Made it possible for mouse wheel and navigation-triggered scrolling to override a call to
  SetScrollX()/SetScrollY(), making it possible to use a simpler stateless pattern for auto-scrolling:
     // (Submit items..)
     if (ImGui::GetScrollY() >= ImGui::GetScrollMaxY())  // If scrolling at the already at the bottom..
         ImGui::SetScrollHereY(1.0f);                    // ..make last item fully visible
- Scrolling: Added SetScrollHereX(), SetScrollFromPosX() for completeness. (#1580) [@kevreco]
- Scrolling: Mouse wheel scrolling while hovering a child window is automatically forwarded to parent window
  if ScrollMax is zero on the scrolling axis.
  Also still the case if ImGuiWindowFlags_NoScrollWithMouse is set (not new), but previously the forwarding
  would be disabled if ImGuiWindowFlags_NoScrollbar was set on the child window, which is not the case
  any more. Forwarding can still be disabled by setting ImGuiWindowFlags_NoInputs. (amend #1502, #1380).
- Window: Fixed InnerClipRect right-most coordinates using wrong padding setting (introduced in 1.71).
- Window: Fixed old SetWindowFontScale() api value from not being inherited by child window. Added
  comments about the right way to scale your UI (load a font at the right side, rebuild atlas, scale style).
- Scrollbar: Avoid overlapping the opposite side when window (often a child window) is forcibly too small.
- Combo: Hide arrow when there's not enough space even for the square button.
- InputText: Testing for newly added ImGuiKey_KeyPadEnter key. (#2677, #2005) [@amc522]
- TabBar: Fixed unfocused tab bar separator color (was using ImGuiCol_Tab, should use ImGuiCol_TabUnfocusedActive).
- Columns: Fixed a regression from 1.71 where the right-side of the contents rectangle within each column
  would wrongly use a WindowPadding.x instead of ItemSpacing.x like it always did. (#125, #2666)
- Columns: Made the right-most edge reaches up to the clipping rectangle (removing half of WindowPadding.x
  worth of asymmetrical/extraneous padding, note that there's another half that conservatively has to offset
  the right-most column, otherwise it's clipping width won't match the other columns). (#125, #2666)
- Columns: Improved honoring alignment with various values of ItemSpacing.x and WindowPadding.x. (#125, #2666)
- Columns: Made GetColumnOffset() and GetColumnWidth() behave when there's no column set, consistently with
  other column functions. (#2683)
- InputTextMultiline: Fixed vertical scrolling tracking glitch.
- Word-wrapping: Fixed overzealous word-wrapping when glyph edge lands exactly on the limit. Because
  of this, auto-fitting exactly unwrapped text would make it wrap. (fixes initial 1.15 commit, 78645a7d).
- Style: Attenuated default opacity of ImGuiCol_Separator in Classic and Light styles.
- Style: Added style.ColorButtonPosition (left/right, defaults to ImGuiDir_Right) to move the color button
  of ColorEdit3/ColorEdit4 functions to either side of the inputs.
- IO: Added ImGuiKey_KeyPadEnter and support in various backends (previously backends would need to
  specifically redirect key-pad keys to their regular counterpart). This is a temporary attenuating measure
  until we actually refactor and add whole sets of keys into the ImGuiKey enum. (#2677, #2005) [@amc522]
- Misc: Made Button(), ColorButton() not trigger an "edited" event leading to IsItemDeactivatedAfterEdit()
  returning true. This also effectively make ColorEdit4() not incorrect trigger IsItemDeactivatedAfterEdit()
  when clicking the color button to open the picker popup. (#1875)
- Misc: Added IMGUI_DISABLE_METRICS_WINDOW imconfig.h setting to explicitly compile out ShowMetricsWindow().
- Debug, Metrics: Added "Tools->Item Picker" tool which allow clicking on a widget to break in the debugger
  within the item code. The tool calls IM_DEBUG_BREAK() which can be redefined in imconfig.h if needed.
- ImDrawList: Fixed CloneOutput() helper crashing. (#1860) [@gviot]
- ImDrawList::ChannelsSplit(), ImDrawListSplitter: Fixed an issue with merging draw commands between
  channel 0 and 1. (#2624)
- ImDrawListSplitter: Fixed memory leak when using low-level split api (was not affecting ImDrawList api,
  also this type was added in 1.71 and not advertised as a public-facing feature).
- Fonts: binary_to_compressed_c.cpp: Display an error message if failing to open/read the input font file.
- Demo: Log, Console: Using a simpler stateless pattern for auto-scrolling.
- Demo: Widgets: Showing how to use the format parameter of Slider/Drag functions to display the name
  of an enum value instead of the underlying integer value.
- Demo: Renamed the "Help" menu to "Tools" (more accurate).
- Backends: DX10/DX11: Backup, clear and restore Geometry Shader is any is bound when calling renderer.
- Backends: DX11: Clear Hull Shader, Domain Shader, Compute Shader before rendering. Not backing/restoring them.
- Backends: OSX: Disabled default native Mac clipboard copy/paste implementation in core library (added in 1.71),
  because it needs application to be linked with '-framework ApplicationServices'. It can be explicitly
  enabled back by using '#define IMGUI_ENABLE_OSX_DEFAULT_CLIPBOARD_FUNCTIONS' in imconfig.h. Re-added
  equivalent using NSPasteboard api in the imgui_impl_osx.mm experimental backend. (#2546)
- Backends: SDL2: Added ImGui_ImplSDL2_InitForD3D() function to make D3D support more visible.
  (#2482, #2632) [@josiahmanson]
- Examples: Added SDL2+DirectX11 example application. (#2632, #2612, #2482) [@vincenthamm]

Docking+Viewports Branch:

- Docking: Making it possible to undock a node by clicking on the tab bar / title bar for the node. (#2645).
- Docking: Explicitly inhibit constraint when docked for now. Fix clipping issue related to constraints. (#2690).
- Docking: Fixed dragging/resizing from OS decoration not marking settings as dirty.
- Docking: Renamed io.ConfigDockingTabBarOnSingleWindows to io.ConfigDockingAlwaysTabBar.
  Added ImGuiWindowClass::DockingAlwaysTabBar to set on individual windows.
- Docking: Perform simple check: assert if Docking or Viewport are enabled exactly on frame 1 (instead of frame 0
  or later), which is a common user error leading to loss of .ini data on load.
- Docking: Fix so that an appearing window making a dock node reappear won't have a zero-size on its first frame.
- Docking: Fixed using ImGuiDockNodeFlags_AutoHideTabBar with io.ConfigDockingTabBarOnSingleWindows.
- Docking: Added ImGuiDockNode to .natvis file.
- Docking: Fixed support for large meshes in GetBackgroundDrawList(), GetForegroundDrawList(). (#2638)
- Viewport: Fix monitor dpi info not being copied to main viewport when multi-viewports are not enabled. (#2621, #1676)
- Viewport: Refactored ImGuiWindowClass's ViewportFlagsOverrideMask + ViewportFlagsOverrideValue into
  ViewportFlagsOverrideSet + ViewportFlagsOverrideClear which appears easier to grasp. (#1542)
- Viewport: Added ImGuiViewportFlags_NoAutoMerge to prevent merging into host viewport in a per-window basis
  via the ImGuiWindowClass override mechanism. (#1542)


-----------------------------------------------------------------------
 VERSION 1.71 (Released 2019-06-12)
-----------------------------------------------------------------------

Decorated log: https://github.com/ocornut/imgui/releases/tag/v1.71

Breaking Changes:

- IO: changed AddInputCharacter(unsigned short c) signature to AddInputCharacter(unsigned int c).
- Renamed SetNextTreeNodeOpen() to SetNextItemOpen(). Kept inline redirection function (will obsolete).
- Window: rendering of child windows outer decorations (e.g. bg color, border, scrollbars) is now
  performed as part of their parent window, avoiding the creation of an extraneous draw commands.
  If you have overlapping child windows with decorations, and relied on their relative z-order to be
  mapped to submission their order, this will affect your rendering. The optimization is disabled
  if the parent window has no visual output because it appears to be the most common situation leading
  to the creation of overlapping child windows. Please reach out if you are affected by this change!

Other Changes:

- Window: clarified behavior of SetNextWindowContentSize(). Content size is defined as the size available
  after removal of WindowPadding on each sides. So SetNextWindowContentSize(ImVec2(100,100)) + auto-resize
  will always allow submitting a 100x100 item without creating a scrollbar, regarding of WindowPadding.
  The exact meaning of ContentSize for decorated windows was previously ill-defined.
- Window: Fixed auto-resize with AlwaysVerticalScrollbar or AlwaysHorizontalScrollbar flags.
- Window: Fixed one case where auto-resize by double-clicking the resize grip would make either scrollbar
  appear for a single frame after the resize.
- Separator: Revert 1.70 "Declare its thickness (1.0f) to the layout" change. It's not incorrect
  but it breaks existing some layout patterns. Will return back to it when we expose Separator flags.
- Fixed InputScalar, InputScalarN, SliderScalarN, DragScalarN with non-visible label from inserting
  style.ItemInnerSpacing.x worth of trailing spacing.
- Fixed InputFloatX, SliderFloatX, DragFloatX functions erroneously reporting IsItemEdited() multiple
  times when the text input doesn't match the formatted output value (e.g. input "1" shows "1.000").
  It wasn't much of a problem because we typically use the return value instead of IsItemEdited() here.
- Fixed uses of IsItemDeactivated(), IsItemDeactivatedAfterEdit() on multi-components widgets and
  after EndGroup(). (#2550, #1875)
- Fixed crash when appending with BeginMainMenuBar() more than once and no other window are showing. (#2567)
- ColorEdit: Fixed the color picker popup only displaying inputs as HSV instead of showing multiple
  options. (#2587, broken in 1.69 by #2384).
- CollapsingHeader: Better clipping when a close button is enabled and it overlaps the label. (#600)
- Scrollbar: Minor bounding box adjustment to cope with various border size.
- Scrollbar, Style: Changed default style.ScrollbarSize from 16 to 14.
- Combo: Fixed rounding not applying with the ImGuiComboFlags_NoArrowButton flag. (#2607) [@DucaRii]
- Nav: Fixed gamepad/keyboard moving of window affecting contents size incorrectly, sometimes leading
  to scrollbars appearing during the movement.
- Nav: Fixed rare crash when e.g. releasing Alt-key while focusing a window with a menu at the same
  frame as clearing the focus. This was in most noticeable in backends such as Glfw and SDL which
  emits key release events when focusing another viewport, leading to Alt+clicking on void on another
  viewport triggering the issue. (#2609)
- TreeNode, CollapsingHeader: Fixed highlight frame not covering horizontal area fully when using
  horizontal scrolling. (#2211, #2579)
- TabBar: Fixed BeginTabBar() within a window with horizontal scrolling from creating a feedback
  loop with the horizontal contents size.
- Columns: Fixed Columns() within a window with horizontal scrolling from not covering the full
  horizontal area (previously only worked with an explicit contents size). (#125)
- Columns: Fixed Separator from creating an extraneous draw command. (#125)
- Columns: Fixed Selectable with SpanAllColumns flag from creating an extraneous draw command. (#125)
- Style: Added style.WindowMenuButtonPosition (left/right, defaults to ImGuiDir_Left) to move the
  collapsing/docking button to the other side of the title bar.
- Style: Made window close button cross slightly smaller.
- Log/Capture: Fixed BeginTabItem() label not being included in a text log/capture.
- ImDrawList: Added ImDrawCmd::VtxOffset value to support large meshes (64k+ vertices) using 16-bit indices.
  The renderer backend needs to set 'io.BackendFlags |= ImGuiBackendFlags_RendererHasVtxOffset' to enable
  this, and honor the ImDrawCmd::VtxOffset field. Otherwise the value will always be zero. (#2591)
  This has the advantage of preserving smaller index buffers and allowing to execute on hardware that do not
  support 32-bit indices. Most examples backends have been modified to support the VtxOffset field.
- ImDrawList: Added ImDrawCmd::IdxOffset value, equivalent to summing element count for each draw command.
  This is provided for convenience and consistency with VtxOffset. (#2591)
- ImDrawCallback: Allow to override the signature of ImDrawCallback by #define-ing it. This is meant to
  facilitate custom rendering backends passing local render-specific data to the draw callback.
- ImFontAtlas: FreeType: Added RasterizerFlags::Monochrome flag to disable font anti-aliasing. Combine
  with RasterizerFlags::MonoHinting for best results. (#2545) [@HolyBlackCat]
- ImFontGlyphRangesBuilder: Fixed unnecessarily over-sized buffer, which incidentally was also not
  fully cleared. Fixed edge-case overflow when adding character 0xFFFF. (#2568). [@NIKE3500]
- Demo: Added full "Dear ImGui" prefix to the title of "Dear ImGui Demo" and "Dear ImGui Metrics" windows.
- Backends: Add native Mac clipboard copy/paste default implementation in core library to match what we are
  dealing with Win32, and to facilitate integration in custom engines. (#2546) [@andrewwillmott]
- Backends: OSX: imgui_impl_osx: Added mouse cursor support. (#2585, #1873) [@actboy168]
- Examples/Backends: DirectX9/10/11/12, Metal, Vulkan, OpenGL3 (Desktop GL only): Added support for large meshes
  (64k+ vertices) with 16-bit indices, enable 'ImGuiBackendFlags_RendererHasVtxOffset' in those backends. (#2591)
- Examples/Backends: Don't filter characters under 0x10000 before calling io.AddInputCharacter(),
  the filtering is done in io.AddInputCharacter() itself. This is in prevision for fuller Unicode
  support. (#2538, #2541)


-----------------------------------------------------------------------
 VERSION 1.70 (Released 2019-05-06)
-----------------------------------------------------------------------

Decorated log: https://github.com/ocornut/imgui/releases/tag/v1.70

Breaking Changes:

- ImDrawList: Improved algorithm for mitre joints on thick lines, preserving correct thickness
  up to 90 degrees angles (e.g. rectangles). If you have custom rendering using thick lines,
  they will appear a little thicker now. (#2518) [@rmitton]
- Obsoleted GetContentRegionAvailWidth(), use GetContentRegionAvail().x instead.
  Kept inline redirection function.
- Examples: Vulkan: Added MinImageCount/ImageCount fields in ImGui_ImplVulkan_InitInfo, required
  during initialization to specify the number of in-flight image requested by swap chains.
  (was previously a hard #define IMGUI_VK_QUEUED_FRAMES 2). (#2071, #1677) [@nathanvoglsam]
- Examples: Vulkan: Tidying up the demo/internals helpers (most engine/app should not rely
  on them but it is possible you have!).

Other Changes:

- ImDrawList: Added ImDrawCallback_ResetRenderState, a special ImDrawList::AddCallback() value
  to request the renderer backend to reset its render state. (#2037, #1639, #2452)
  Examples: Added support for ImDrawCallback_ResetRenderState in all renderer backends. Each
  renderer code setting up initial render state has been moved to a function so it could be
  called at the start of rendering and when a ResetRenderState is requested. [@ocornut, @bear24rw]
- InputText: Fixed selection background rendering one frame after the cursor movement when
  first transitioning from no-selection to has-selection. (Bug in 1.69) (#2436) [@Nazg-Gul]
- InputText: Work-around for buggy standard libraries where isprint('\t') returns true. (#2467, #1336)
- InputText: Fixed ImGuiInputTextFlags_AllowTabInput leading to two tabs characters being inserted
  if the backend provided both Key and Character input. (#2467, #1336)
- Layout: Added SetNextItemWidth() helper to avoid using PushItemWidth/PopItemWidth() for single items.
  Note that SetNextItemWidth() currently only affect the same subset of items as PushItemWidth(),
  generally referred to as the large framed+labeled items. Because the new SetNextItemWidth()
  function is explicit we may later extend its effect to more items.
- Layout: Fixed PushItemWidth(-width) for right-side alignment laying out some items (button, listbox, etc.)
  with negative sizes if the 'width' argument was smaller than the available width at the time of item
  submission.
- Window: Fixed window with the AlwaysAutoResize flag unnecessarily extending their hovering boundaries
  by a few pixels (this is used to facilitate resizing from borders when available for a given window).
  One of the noticeable minor side effect was that navigating menus would have had a tendency to disable
  highlight from parent menu items earlier than necessary while approaching the child menu.
- Window: Close button is horizontally aligned with style.FramePadding.x.
- Window: Fixed contents region being off by WindowBorderSize amount on the right when scrollbar is active.
- Window: Fixed SetNextWindowSizeConstraints() with non-rounded positions making windows drift. (#2067, #2530)
- Popups: Closing a popup restores the focused/nav window in place at the time of the popup opening,
  instead of restoring the window that was in the window stack at the time of the OpenPopup call. (#2517)
  Among other things, this allows opening a popup while no window are focused, and pressing Escape to
  clear the focus again.
- Popups: Fixed right-click from closing all popups instead of aiming at the hovered popup level
  (regression in 1.67).
- Selectable: With ImGuiSelectableFlags_AllowDoubleClick doesn't return true on the mouse button release
  following the double-click. Only first mouse release + second mouse down (double-click) returns true.
  Likewise for internal ButtonBehavior() with both _PressedOnClickRelease | _PressedOnDoubleClick. (#2503)
- GetMouseDragDelta(): also returns the delta on the mouse button released frame. (#2419)
- GetMouseDragDelta(): verify that mouse positions are valid otherwise returns zero.
- Inputs: Also add support for horizontal scroll with Shift+Mouse Wheel. (#2424, #1463) [@LucaRood]
- PlotLines, PlotHistogram: Ignore NaN values when calculating min/max bounds. (#2485)
- Columns: Fixed boundary of clipping being off by 1 pixel within the left column. (#125)
- Separator: Declare its thickness (1.0f) to the layout, making items around separator more symmetrical.
- Combo, Slider, Scrollbar: Improve rendering in situation when there's only a few pixels available (<3 pixels).
- Nav: Fixed Drag/Slider functions going into text input mode when keyboard CTRL is held while pressing NavActivate.
- Drag and Drop: Fixed drag source with ImGuiDragDropFlags_SourceAllowNullID and null ID from receiving click
  regardless of being covered by another window (it didn't honor correct hovering rules). (#2521)
- ImDrawList: Improved algorithm for mitre joints on thick lines, preserving correct thickness up to 90 degrees
  angles, also faster to output. (#2518) [@rmitton]
- Misc: Added IM_MALLOC/IM_FREE macros mimicking IM_NEW/IM_DELETE so user doesn't need to revert
  to using the ImGui::MemAlloc()/MemFree() calls directly.
- Misc: Made IMGUI_CHECKVERSION() macro also check for matching size of ImDrawIdx.
- Metrics: Added "Show windows rectangles" tool to visualize the different rectangles.
- Demo: Improved trees in columns demo.
- Examples: OpenGL: Added a test GL call + comments in ImGui_ImplOpenGL3_Init() to detect uninitialized
  GL function loaders early, and help users understand what they are missing. (#2421)
- Examples: SDL: Added support for SDL_GameController gamepads (enable with ImGuiConfigFlags_NavEnableGamepad). (#2509) [@DJLink]
- Examples: Emscripten: Added Emscripten+SDL+GLES2 example. (#2494, #2492, #2351, #336) [@nicolasnoble, @redblobgames]
- Examples: Metal: Added Glfw+Metal example. (#2527) [@bear24rw]
- Examples: OpenGL3: Minor tweaks + not calling glBindBuffer more than necessary in the render loop.
- Examples: Vulkan: Fixed in-flight buffers issues when using multi-viewports. (#2461, #2348, #2378, #2097)
- Examples: Vulkan: Added missing support for 32-bit indices (#define ImDrawIdx unsigned int).
- Examples: Vulkan: Avoid passing negative coordinates to vkCmdSetScissor, which debug validation layers do not like.
- Examples: Vulkan: Added ImGui_ImplVulkan_SetMinImageCount() to change min image count at runtime. (#2071) [@nathanvoglsam]
- Examples: DirectX9: Fixed erroneous assert in ImGui_ImplDX9_InvalidateDeviceObjects(). (#2454)
- Examples: DirectX10/11/12, Allegro, Marmalade: Render functions early out when display size is zero (minimized). (#2496)
- Examples: GLUT: Fixed existing FreeGLUT example to work with regular GLUT. (#2465) [@andrewwillmott]
- Examples: GLUT: Renamed imgui_impl_freeglut.cpp/.h to imgui_impl_glut.cpp/.h. (#2465) [@andrewwillmott]
- Examples: GLUT: Made io.DeltaTime always > 0. (#2430)
- Examples: Visual Studio: Updated default platform toolset+sdk in vcproj files from v100+sdk7 (vs2010)
  to v110+sdk8 (vs2012). This is mostly so we can remove reliance on DXSDK_DIR for the DX10/DX11 example,
  which if existing and when switching to recent SDK ends up conflicting and creating warnings.


-----------------------------------------------------------------------
 VERSION 1.69 (Released 2019-03-13)
-----------------------------------------------------------------------

Decorated log: https://github.com/ocornut/imgui/releases/tag/v1.69

Breaking Changes:

- Renamed ColorEdit/ColorPicker's ImGuiColorEditFlags_RGB/_HSV/_HEX flags to respectively
  ImGuiColorEditFlags_DisplayRGB/_DisplayHSV/_DisplayHex. This is because the addition of
  new flag ImGuiColorEditFlags_InputHSV makes the earlier one ambiguous.
  Kept redirection enum values (will obsolete). (#2384) [@haldean]
- Renamed GetOverlayDrawList() to GetForegroundDrawList(). Kept redirection function (will obsolete). (#2391)

Other Changes:

- Added GetBackgroundDrawList() helper to quickly get access to a ImDrawList that will be rendered
  behind every other windows. (#2391, #545)
- DragScalar, InputScalar, SliderScalar: Added support for u8/s8/u16/s16 data types (ImGuiDataType_S8, etc.)
  We are reusing function instances of larger types to reduce code size. (#643, #320, #708, #1011)
- Added InputTextWithHint() to display a description/hint in the text box when no text
  has been entered. (#2400) [@Organic-Code, @ocornut]
- Nav: Fixed a tap on AltGR (e.g. German keyboard) from navigating to the menu layer.
- Nav: Fixed Ctrl+Tab keeping active InputText() of a previous window active after the switch. (#2380)
- Fixed IsItemDeactivated()/IsItemDeactivatedAfterEdit() from not correctly returning true
  when tabbing out of a focusable widget (Input/Slider/Drag) in most situations. (#2215, #1875)
- InputInt, InputFloat, InputScalar: Fix to keep the label of the +/- buttons centered when
  style.FramePadding.x is abnormally larger than style.FramePadding.y. Since the buttons are
  meant to be square (to align with e.g. color button) we always use FramePadding.y. (#2367)
- InputInt, InputScalar: +/- buttons now respects the natural type limits instead of
  overflowing or underflowing the value.
- InputText: Fixed an edge case crash that would happen if another widget sharing the same ID
  is being swapped with an InputText that has yet to be activated.
- InputText: Fixed various display corruption related to swapping the underlying buffer while
  a input widget is active (both for writable and read-only paths). Often they would manifest
  when manipulating the scrollbar of a multi-line input text.
- ColorEdit, ColorPicker, ColorButton: Added ImGuiColorEditFlags_InputHSV to manipulate color
  values encoded as HSV (in order to avoid HSV<>RGB round trips and associated singularities).
  (#2383, #2384) [@haldean]
- ColorPicker: Fixed a bug/assertion when displaying a color picker in a collapsed window
  while dragging its title bar. (#2389)
- ColorEdit: Fixed tooltip not honoring the ImGuiColorEditFlags_NoAlpha contract of never
  reading the 4th float in the array (value was read and discarded). (#2384) [@haldean]
- MenuItem, Selectable: Fixed disabled widget interfering with navigation (fix c2db7f63 in 1.67).
- TabBar: Fixed a crash when using many BeginTabBar() recursively (didn't affect docking). (#2371)
- TabBar: Added extra mis-usage error recovery. Past the assert, common mis-usage don't lead to
  hard crashes any more, facilitating integration with scripting languages. (#1651)
- TabBar: Fixed ImGuiTabItemFlags_SetSelected being ignored if the tab is not visible (with
  scrolling policy enabled) or if is currently appearing.
- TabBar: Fixed Tab tooltip code making drag and drop tooltip disappear during the frame where
  the drag payload activate a tab.
- TabBar: Reworked scrolling policy (when ImGuiTabBarFlags_FittingPolicyScroll is set) to
  teleport the view when aiming at a tab far away the visible section, and otherwise accelerate
  the scrolling speed to cap the scrolling time to 0.3 seconds.
- Text: Fixed large Text/TextUnformatted calls not feeding their size into layout when starting
  below the lower point of the current clipping rectangle. This bug has been there since v1.0!
  It was hardly noticeable but would affect the scrolling range, which in turn would affect
  some scrolling request functions when called during the appearing frame of a window.
- Plot: Fixed divide-by-zero in PlotLines() when passing a count of 1. (#2387) [@Lectem]
- Log/Capture: Fixed LogXXX functions emitting extraneous leading carriage return.
- Log/Capture: Fixed an issue when empty string on a new line would not emit a carriage return.
- Log/Capture: Fixed LogXXX functions 'auto_open_depth' parameter being treated as an absolute
  tree depth instead of a relative one.
- Log/Capture: Fixed CollapsingHeader trailing ascii representation being "#" instead of "##".
- ImFont: Added GetGlyphRangesVietnamese() helper. (#2403)
- Misc: Asserting in NewFrame() if style.WindowMinSize is zero or smaller than (1.0f,1.0f).
- Demo: Using GetBackgroundDrawList() and GetForegroundDrawList() in "Custom Rendering" demo.
- Demo: InputText: Demonstrating use of ImGuiInputTextFlags_CallbackResize. (#2006, #1443, #1008).
- Examples: GLFW, SDL: Preserve DisplayFramebufferScale when main viewport is minimized.
  (This is particularly useful for the viewport branch because we are not supporting per-viewport
  frame-buffer scale. It fixes windows not refreshing when main viewport is minimized.) (#2416)
- Examples: OpenGL: Fix to be able to run on ES 2.0 / WebGL 1.0. [@rmitton, @gabrielcuvillier]
- Examples: OpenGL: Fix for OSX not supporting OpenGL 4.5, we don't try to read GL_CLIP_ORIGIN
  even if the OpenGL headers/loader happens to define the value. (#2366, #2186)
- Examples: Allegro: Added support for touch events (emulating mouse). (#2219) [@dos1]
- Examples: DirectX9: Minor changes to match the other DirectX examples more closely. (#2394)


-----------------------------------------------------------------------
 VERSION 1.68 (Released 2019-02-19)
-----------------------------------------------------------------------

Decorated log: https://github.com/ocornut/imgui/releases/tag/v1.68

Breaking Changes:

- Removed io.DisplayVisibleMin/DisplayVisibleMax (which were marked obsolete and removed from viewport/docking branch already).
- Made it illegal/assert when io.DisplayTime == 0.0f (with an exception for the first frame).
  If for some reason your time step calculation gives you a zero value, replace it with a arbitrarily small value!

Other Changes:

- Added .editorconfig file for text editors to standardize using spaces. (#2038) [@kudaba]
- ImDrawData: Added FramebufferScale field (currently a copy of the value from io.DisplayFramebufferScale).
  This is to allow render functions being written without pulling any data from ImGuiIO, allowing incoming
  multi-viewport feature to behave on Retina display and with multiple displays.
  If you are not using a custom backend, please update your render function code ahead of time,
  and use draw_data->FramebufferScale instead of io.DisplayFramebufferScale. (#2306, #1676)
- Added IsItemActivated() as an extension to the IsItemDeactivated/IsItemDeactivatedAfterEdit functions
  which are useful to implement variety of undo patterns. (#820, #956, #1875)
- InputText: Fixed a bug where ESCAPE would not restore the initial value in all situations. (#2321) [@relick]
- InputText: Fixed a bug where ESCAPE would be first captured by the Keyboard Navigation code. (#2321, #787)
- InputText: Fixed redo buffer exhaustion handling (rare) which could corrupt the undo character buffer. (#2333)
  The way the redo/undo buffers work would have made it generally unnoticeable to the user.
- Fixed range-version of PushID() and GetID() not honoring the ### operator to restart from the seed value.
- Fixed CloseCurrentPopup() on a child-menu of a modal incorrectly closing the modal. (#2308)
- Tabs: Added ImGuiTabBarFlags_TabListPopupButton flag to show a popup button on manual tab bars. (#261, #351)
- Tabs: Removed ImGuiTabBarFlags_NoTabListPopupButton which was available in 1.67 but actually had zero use.
- Tabs: Fixed a minor clipping glitch when changing style's FramePadding from frame to frame.
- Tabs: Fixed border (when enabled) so it is aligned correctly mid-pixel and appears as bright as other borders.
- Style, Selectable: Added ImGuiStyle::SelectableTextAlign and ImGuiStyleVar_SelectableTextAlign. (#2347) [@haldean]
- Menus: Tweaked horizontal overlap between parent and child menu (to help convey relative depth)
  from using style.ItemSpacing.x to style.ItemInnerSpacing.x, the later being expected to be smaller. (#1086)
- RadioButton: Fixed label horizontal alignment to precisely match Checkbox().
- Window: When resizing from an edge, the border is more visible and better follow the rounded corners.
- Window: Fixed initial width of collapsed windows not taking account of contents width (broken in 1.67). (#2336, #176)
- Scrollbar: Fade out and disable interaction when too small, in order to facilitate using the resize grab on very
  small window, as well as reducing visual noise/overlap.
- ListBox: Better optimized when clipped / non-visible.
- InputTextMultiline: Better optimized when clipped / non-visible.
- Font: Fixed high-level ImGui::CalcTextSize() used by most widgets from erroneously subtracting 1.0f*scale to
  calculated text width. Among noticeable side-effects, it would make sequences of repeated Text/SameLine calls
  not align the same as a single call, and create mismatch between high-level size calculation and those performed
  with the lower-level ImDrawList api. (#792) [@SlNPacifist]
- Font: Fixed building atlas when specifying duplicate/overlapping ranges within a same font. (#2353, #2233)
- ImDrawList: Fixed AddCircle(), AddCircleFilled() angle step being off, which was visible when drawing a "circle"
  with a small number of segments (e.g. an hexagon). (#2287) [@baktery]
- ImGuiTextBuffer: Added append() function (unformatted).
- ImFontAtlas: Added 0x2000-0x206F general punctuation range to default ChineseFull/ChineseSimplifiedCommon ranges. (#2093)
- ImFontAtlas: FreeType: Added support for imgui allocators + custom FreeType only SetAllocatorFunctions. (#2285) [@Vuhdo]
- ImFontAtlas: FreeType: Fixed using imgui_freetype.cpp in unity builds. (#2302)
- Demo: Fixed "Log" demo not initializing properly, leading to the first line not showing before a Clear. (#2318) [@bluescan]
- Demo: Added "Auto-scroll" option in Log/Console demos. (#2300) [@nicolasnoble, @ocornut]
- Examples: Metal, OpenGL2, OpenGL3, Vulkan: Fixed offsetting of clipping rectangle with ImDrawData::DisplayPos != (0,0)
  when the display frame-buffer scale scale is not (1,1). While this doesn't make a difference when using master branch,
  this is effectively fixing support for multi-viewport with Mac Retina Displays on those examples. (#2306) [@rasky, @ocornut]
  Also using ImDrawData::FramebufferScale instead of io.DisplayFramebufferScale.
- Examples: Clarified the use the ImDrawData::DisplayPos to offset clipping rectangles.
- Examples: Win32: Using GetForegroundWindow()+IsChild() instead of GetActiveWindow() to be compatible with windows created
  in a different thread or parent. (#1951, #2087, #2156, #2232) [many people]
- Examples: SDL: Using the SDL_WINDOW_ALLOW_HIGHDPI flag. (#2306, #1676) [@rasky]
- Examples: Win32: Added support for XInput gamepads (if ImGuiConfigFlags_NavEnableGamepad is enabled).
- Examples: Win32: Added support for mouse buttons 4 and 5 via WM_XBUTTON* messages. (#2264)
- Examples: DirectX9: Explicitly disable fog (D3DRS_FOGENABLE) before drawing in case user state has it set. (#2288, #2230)
- Examples: OpenGL2: Added #define GL_SILENCE_DEPRECATION to cope with newer XCode warnings.
- Examples: OpenGL3: Using GLSL 4.10 shaders for any GLSL version over 410 (e.g. 430, 450). (#2329) [@BrutPitt]


-----------------------------------------------------------------------
 VERSION 1.67 (Released 2019-01-14)
-----------------------------------------------------------------------

Decorated log: https://github.com/ocornut/imgui/releases/tag/v1.67

Breaking Changes:

- Made it illegal to call Begin("") with an empty string. This somehow half-worked before but had various undesirable
  side-effect because the window would have ID zero. In particular it is causing problems in viewport/docking branches.
- Renamed io.ConfigResizeWindowsFromEdges to io.ConfigWindowsResizeFromEdges and removed its [Beta] mark.
  The addition of new configuration options in the Docking branch is pushing for a little reorganization of those names.
- Renamed ImFontAtlas::GlyphRangesBuilder to ImFontGlyphRangesBuilder. Kept redirection typedef (will obsolete).

Other Changes:

- Added BETA api for Tab Bar/Tabs widgets: (#261, #351)
  - Added BeginTabBar(), EndTabBar(), BeginTabItem(), EndTabItem(), SetTabItemClosed() API.
  - Added ImGuiTabBarFlags flags for BeginTabBar().
  - Added ImGuiTabItemFlags flags for BeginTabItem().
  - Style: Added ImGuiCol_Tab, ImGuiCol_TabHovered, ImGuiCol_TabActive, ImGuiCol_TabUnfocused, ImGuiCol_TabUnfocusedActive colors.
  - Demo: Added Layout->Tabs demo code.
  - Demo: Added "Documents" example app showcasing possible use for tabs.
  This feature was merged from the Docking branch in order to allow the use of regular tabs in your code.
  (It does not provide the docking/splitting/merging of windows available in the Docking branch)
- Added ImGuiWindowFlags_UnsavedDocument window flag to append '*' to title without altering the ID, as a convenience
  to avoid using the ### operator. In the Docking branch this also has an effect on tab closing behavior.
- Window, Focus, Popup: Fixed an issue where closing a popup by clicking another window with the _NoMove flag would refocus
  the parent window of the popup instead of the newly clicked window.
- Window: Contents size is preserved while a window collapsed. Fix auto-resizing window losing their size for one frame when uncollapsed.
- Window: Contents size is preserved while a window contents is hidden (unless it is hidden for resizing purpose).
- Window: Resizing windows from edge is now enabled by default (io.ConfigWindowsResizeFromEdges=true). Note that
  it only works _if_ the backend sets ImGuiBackendFlags_HasMouseCursors, which the standard backends do.
- Window: Added io.ConfigWindowsMoveFromTitleBarOnly option. This is ignored by window with no title bars (often popups).
  This affects clamping window within the visible area: with this option enabled title bars need to be visible. (#899)
- Window: Fixed using SetNextWindowPos() on a child window (which wasn't really documented) position the cursor as expected
  in the parent window, so there is no mismatch between the layout in parent and the position of the child window.
- InputFloat: When using ImGuiInputTextFlags_ReadOnly the step buttons are disabled. (#2257)
- DragFloat: Fixed broken mouse direction change with power!=1.0. (#2174, #2206) [@Joshhua5]
- Nav: Fixed an keyboard issue where holding Activate/Space for longer than two frames on a button would unnecessary
  keep the focus on the parent window, which could steal it from newly appearing windows. (#787)
- Nav: Fixed animated window titles from being updated when displayed in the CTRL+Tab list. (#787)
- Error recovery: Extraneous/undesired calls to End() are now being caught by an assert in the End() function closer
  to the user call site (instead of being reported in EndFrame). Past the assert, they don't lead to crashes any more. (#1651)
  Missing calls to End(), past the assert, should not lead to crashes or to the fallback Debug window appearing on screen.
  Those changes makes it easier to integrate dear imgui with a scripting language allowing, given asserts are redirected
  into e.g. an error log and stopping the script execution.
- ImFontAtlas: Stb and FreeType: Atlas width is now properly based on total surface rather than glyph count (unless overridden with TexDesiredWidth).
- ImFontAtlas: Stb and FreeType: Fixed atlas builder so missing glyphs won't influence the atlas texture width. (#2233)
- ImFontAtlas: Stb and FreeType: Fixed atlas builder so duplicate glyphs (when merging fonts) won't be included in the rasterized atlas.
- ImFontAtlas: FreeType: Fixed abnormally high atlas height.
- ImFontAtlas: FreeType: Fixed support for any values of TexGlyphPadding (not just only 1).
- ImDrawList: Optimized some of the functions for performance of debug builds where non-inline function call cost are non-negligible.
  (Our test UI scene on VS2015 Debug Win64 with /RTC1 went ~5.9 ms -> ~4.9 ms. In Release same scene stays at ~0.3 ms.)
- IO: Added BackendPlatformUserData, BackendRendererUserData, BackendLanguageUserData void* for storage use by backends.
- IO: Renamed InputCharacters[], marked internal as was always intended. Please don't access directly, and use AddInputCharacter() instead!
- IO: AddInputCharacter() goes into a queue which can receive as many characters as needed during the frame. This is useful
  for automation to not have an upper limit on typing speed. Will later transition key/mouse to use the event queue later.
- Style: Tweaked default value of style.DisplayWindowPadding from (20,20) to (19,19) so the default style as a value
  which is the same as the title bar height.
- Demo: "Simple Layout" and "Style Editor" are now using tabs.
- Demo: Added a few more things under "Child windows" (changing ImGuiCol_ChildBg, positioning child, using IsItemHovered after a child).
- Examples: DirectX10/11/12: Made imgui_impl_dx10/dx11/dx12.cpp link d3dcompiler.lib from the .cpp file to ease integration.
- Examples: Allegro 5: Properly destroy globals on shutdown to allow for restart. (#2262) [@DomRe]


-----------------------------------------------------------------------
 VERSION 1.66b (Released 2018-12-01)
-----------------------------------------------------------------------

Decorated log: https://github.com/ocornut/imgui/releases/tag/v1.66b

Other Changes:

- Fixed a text rendering/clipping bug introduced in 1.66 (on 2018-10-12, commit ede3a3b9) that affect single ImDrawList::AddText()
  calls with single strings larger than 10k. Text/TextUnformatted() calls were not affected, but e.g. InputText() was. [@pdoane]
- When the focused window become inactive don't restore focus to a window with the ImGuiWindowFlags_NoInputs flag. (#2213) [@zzzyap]
- Separator: Fixed Separator() outputting an extraneous empty line when captured into clipboard/text/file.
- Demo: Added ShowAboutWindow() call, previously was only accessible from the demo window.
- Demo: ShowAboutWindow() now display various Build/Config Information (compiler, os, etc.) that can easily be copied into bug reports.
- Fixed build issue with osxcross and macOS. (#2218) [@dos1]
- Examples: Setting up 'io.BackendPlatformName'/'io.BackendRendererName' fields to the current backend can be displayed in the About window.
- Examples: SDL: changed the signature of ImGui_ImplSDL2_ProcessEvent() to use a const SDL_Event*. (#2187)


-----------------------------------------------------------------------
 VERSION 1.66 (Released 2018-11-22)
-----------------------------------------------------------------------

Decorated log: https://github.com/ocornut/imgui/releases/tag/v1.66

Breaking Changes:

- Renamed SetScrollHere() to SetScrollHereY(). Kept redirection function (will obsolete).
- Renamed misc/stl/imgui_stl.* to misc/cpp/imgui_stdlib.* in prevision for other C++ helper files. (#2035, #2096)

Other Changes:

- Fixed calling SetNextWindowSize()/SetWindowSize() with non-integer values leading to
  accidental alteration of window position. We now round the provided size. (#2067)
- Fixed calling DestroyContext() always saving .ini data with the current context instead
  of the supplied context pointer. (#2066)
- Nav, Focus: Fixed ImGuiWindowFlags_NoBringToFrontOnFocus windows not being restoring focus
  properly after the main menu bar or last focused window is deactivated.
- Nav: Fixed an assert in certain circumstance (mostly when using popups) when mouse positions stop being valid. (#2168)
- Nav: Fixed explicit directional input not re-highlighting current nav item if there is a single item in the window
  and highlight has been previously disabled by the mouse. (#787)
- DragFloat: Fixed a situation where dragging with value rounding enabled or with a power curve
  erroneously wrapped the value to one of the min/max edge. (#2024, #708, #320, #2075).
- DragFloat: Disabled using power curve when one edge is FLT_MAX (broken in 1.61). (#2024)
- DragFloat: Disabled setting a default drag speed when one edge is FLT_MAX. (#2024)
- SliderAngle: Added optional format argument to alter precision or localize the string. (#2150) [@podsvirov]
- Window: Resizing from edges (with io.ConfigResizeWindowsFromEdges Beta flag) extends the hit region
  of root floating windows outside the window, making it easier to resize windows. Resize grips are also
  extended accordingly so there are no discontinuity when hovering between borders and corners. (#1495, #822)
- Window: Added ImGuiWindowFlags_NoBackground flag to avoid rendering window background. This is mostly to allow
  the creation of new flag combinations, as we could already use SetNextWindowBgAlpha(0.0f). (#1660) [@biojppm, @ocornut]
- Window: Added ImGuiWindowFlags_NoDecoration helper flag which is essentially NoTitleBar+NoResize+NoScrollbar+NoCollapse.
- Window: Added ImGuiWindowFlags_NoMouseInputs which is basically the old ImGuiWindowFlags_NoInputs (essentially
  we have renamed ImGuiWindowFlags_NoInputs to ImGuiWindowFlags_NoMouseInputs). Made the new ImGuiWindowFlags_NoInputs
  encompass both NoMouseInputs+NoNav, which is consistent with its description. (#1660, #787)
- Window, Inputs: Fixed resizing from edges when io.MousePos is not pixel-rounded by rounding mouse position input. (#2110)
- BeginChild(): Fixed BeginChild(const char*, ...) variation erroneously not applying the ID stack
  to the provided string to uniquely identify the child window. This was undoing an intentional change
  introduced in 1.50 and broken in 1.60. (#1698, #894, #713).
- TextUnformatted(): Fixed a case where large-text path would read bytes past the text_end marker depending
  on the position of new lines in the buffer (it wasn't affecting the output but still not the right thing to do!)
- ListBox(): Fixed frame sizing when items_count==1 unnecessarily showing a scrollbar. (#2173) [@luk1337, @ocornut]
- ListBox(): Tweaked frame sizing so list boxes will look more consistent when FramePadding is far from ItemSpacing.
- RenderText(): Some optimization for very large text buffers, useful for non-optimized builds.
- BeginMenu(): Fixed menu popup horizontal offset being off the item in the menu bar when WindowPadding=0.0f.
- ArrowButton(): Fixed arrow shape being horizontally misaligned by (FramePadding.y-FramePadding.x) if they are different.
- Demo: Split the contents of ShowDemoWindow() into smaller functions as it appears to speed up link time with VS. (#2152)
- Drag and Drop: Added GetDragDropPayload() to peek directly into the payload (if any) from anywhere. (#143)
- ImGuiTextBuffer: Avoid heap allocation when empty.
- ImDrawList: Fixed AddConvexPolyFilled() undefined behavior when passing points_count smaller than 3,
  in particular, points_count==0 could lead to a memory stomp if the draw list was previously empty.
- Examples: DirectX10, DirectX11: Removed seemingly unnecessary calls to invalidate and recreate device objects
  in the WM_SIZE handler. (#2088) [@ice1000]
- Examples: GLFW: User previously installed GLFW callbacks are now saved and chain-called by the default callbacks. (#1759)
- Examples: OpenGL3: Added support for GL 4.5's glClipControl(GL_UPPER_LEFT). (#2186)
- Examples: OpenGL3+GLFW: Fixed error condition when using the GLAD loader. (#2157) [@blackball]
- Examples: OpenGL3+GLFW/SDL: Made main.cpp compile with IMGUI_IMPL_OPENGL_LOADER_CUSTOM (may be missing init). (#2178) [@doug-moen]
- Examples: SDL2+Vulkan: Fixed application shutdown which could deadlock on Linux + Xorg. (#2181) [@eRabbit0]


-----------------------------------------------------------------------
 VERSION 1.65 (Released 2018-09-06)
-----------------------------------------------------------------------

Decorated log: https://github.com/ocornut/imgui/releases/tag/v1.65

Breaking Changes:

- Renamed stb_truetype.h to imstb_truetype.h, stb_textedit.h to imstb_textedit.h, and
  stb_rect_pack.h to imstb_rectpack.h. If you were conveniently using the imgui copy of those
  STB headers in your project, you will have to update your include paths. (#1718, #2036)
  The reason for this change is to avoid conflicts for projects that may also be importing
  their own copy of the STB libraries. Note that imgui's copy of stb_textedit.h is modified.
- Renamed io.ConfigCursorBlink to io.ConfigInputTextCursorBlink. (#1427)

Other Changes:

- This is a minor release following the 1.64 refactor, with a little more shuffling of code.
- Clarified and improved the source code sectioning in all files (easier to search or browse sections).
- Nav: Removed the [Beta] tag from various descriptions of the gamepad/keyboard navigation system.
  Although it is not perfect and will keep being improved, it is fairly functional and used by many. (#787)
- Fixed a build issue with non-Cygwin GCC under Windows.
- Demo: Added a "Configuration" block to make io.ConfigFlags/io.BackendFlags more prominent.
- Examples: OpenGL3+SDL2: Fixed error condition when using the GLAD loader. (#2059, #2002) [@jiri]


-----------------------------------------------------------------------
 VERSION 1.64 (Released 2018-08-31)
-----------------------------------------------------------------------

Decorated log: https://github.com/ocornut/imgui/releases/tag/v1.64

Changes:

- Moved README, CHANGELOG and TODO files to the docs/ folder.
  If you are updating dear imgui by copying files, take the chance to delete the old files.
- Added imgui_widgets.cpp file, extracted and moved widgets code out of imgui.cpp into imgui_widgets.cpp.
  Re-ordered some of the code remaining in imgui.cpp.
  NONE OF THE FUNCTIONS HAVE CHANGED. THE CODE IS SEMANTICALLY 100% IDENTICAL, BUT _EVERY_ FUNCTIONS HAS BEEN MOVED.
  Because of this, any local modifications to imgui.cpp will likely conflict when you update.
  If you have any modifications to imgui.cpp, it is suggested that you first update to 1.63, then
  isolate your patches. You can peak at imgui_widgets.cpp from 1.64 to get a sense of what is included in it,
  then separate your changes into several patches that can more easily be applied to 1.64 on a per-file basis.
  What I found worked nicely for me, was to open the diff of the old patches in an interactive merge/diff tool,
  search for the corresponding function in the new code and apply the chunks manually.
- As a reminder, if you have any change to imgui.cpp it is a good habit to discuss them on the github,
  so a solution applicable on the Master branch can be found. If your company has changes that you cannot
  disclose you may also contact me privately.


-----------------------------------------------------------------------
 VERSION 1.63 (Released 2018-08-29)
-----------------------------------------------------------------------

Decorated log: https://github.com/ocornut/imgui/releases/tag/v1.63

Breaking Changes:

- Style: Renamed ImGuiCol_ModalWindowDarkening to ImGuiCol_ModalWindowDimBg for consistency with other features.
  Kept redirection enum (will obsolete).
- Changed ImGui::GetTime() return value from float to double to avoid accumulating floating point imprecision over time.
- Removed per-window ImGuiWindowFlags_ResizeFromAnySide Beta flag in favor `io.ConfigResizeWindowsFromEdges=true` to
  enable the feature globally. (#1495)
  The feature is not currently enabled by default because it is not satisfying enough, but will eventually be.
- InputText: Renamed ImGuiTextEditCallback to ImGuiInputTextCallback, ImGuiTextEditCallbackData to ImGuiInputTextCallbackData
  for consistency. Kept redirection types (will obsolete).
- InputText: Removed ImGuiTextEditCallbackData::ReadOnly because it is a duplication of (::Flags & ImGuiInputTextFlags_ReadOnly).
- Renamed IsItemDeactivatedAfterChange() to IsItemDeactivatedAfterEdit() for consistency with new IsItemEdited() API.
  Kept redirection function (will obsolete soonish as IsItemDeactivatedAfterChange() is very recent).
- Renamed io.OptCursorBlink to io.ConfigCursorBlink [-> io.ConfigInputTextCursorBlink in 1.65], io.OptMacOSXBehaviors to
  io.ConfigMacOSXBehaviors for consistency. (#1427, #473)
- Removed obsolete redirection functions: CollapsingHeader() variation with 2 bools - marked obsolete in v1.49, May 2016.

Other Changes:

- ArrowButton: Fixed to honor PushButtonRepeat() setting (and internals' ImGuiItemFlags_ButtonRepeat).
- ArrowButton: Setup current line text baseline so that ArrowButton() + SameLine() + Text() are aligned properly.
- Nav: Added a CTRL+TAB window list and changed the highlight system accordingly. The change is motivated by upcoming
  Docking features. (#787)
- Nav: Made CTRL+TAB skip menus + skip the current navigation window if is has the ImGuiWindow_NoNavFocus set. (#787)
  While it was previously possible, you won't be able to CTRL-TAB out and immediately back in a window with the
  ImGuiWindow_NoNavFocus flag.
- Window: Allow menu and popups windows from ignoring the style.WindowMinSize values so short menus/popups are not padded. (#1909)
- Window: Added global io.ConfigResizeWindowsFromEdges option to enable resizing windows from their edges and from
  the lower-left corner. (#1495)
- Window: Collapse button shows hovering highlight + clicking and dragging on it allows to drag the window as well.
- Added IsItemEdited() to query if the last item modified its value (or was pressed). This is equivalent to the bool
  returned by most widgets.
  It is useful in some situation e.g. using InputText() with ImGuiInputTextFlags_EnterReturnsTrue. (#2034)
- InputText: Added support for buffer size/capacity changes via the ImGuiInputTextFlags_CallbackResize flag. (#2006, #1443, #1008).
- InputText: Fixed not tracking the cursor horizontally when modifying the text buffer through a callback.
- InputText: Fixed minor off-by-one issue when submitting a buffer size smaller than the initial zero-terminated buffer contents.
- InputText: Fixed a few pathological crash cases on single-line InputText widget with multiple millions characters worth of contents.
  Because the current text drawing function reserve for a worst-case amount of vertices and how we handle horizontal clipping,
  we currently just avoid displaying those single-line widgets when they are over a threshold of 2 millions characters,
  until a better solution is found.
- Drag and Drop: Fixed an incorrect assert when dropping a source that is submitted after the target (bug introduced with 1.62 changes
  related to the addition of IsItemDeactivated()). (#1875, #143)
- Drag and Drop: Fixed ImGuiDragDropFlags_SourceNoDisableHover to affect hovering state prior to calling IsItemHovered() + fixed description. (#143)
- Drag and Drop: Calling BeginTooltip() between a BeginDragSource()/EndDragSource() or BeginDropTarget()/EndDropTarget() uses adjusted tooltip
  settings matching the one created when calling BeginDragSource() without the ImGuiDragDropFlags_SourceNoPreviewTooltip flag. (#143)
- Drag and Drop: Payload stays available and under the mouse if the source stops being submitted, however the tooltip is replaced by "...". (#1725)
- Drag and Drop: Added ImGuiDragDropFlags_SourceAutoExpirePayload flag to force payload to expire if the source stops being submitted. (#1725, #143).
- IsItemHovered(): Added ImGuiHoveredFlags_AllowWhenDisabled flag to query hovered status on disabled items. (#1940, #211)
- Selectable: Added ImGuiSelectableFlags_Disabled flag in the public API. (#211)
- ColorEdit4: Fixed a bug when text input or drag and drop leading to unsaturated HSV values would erroneously alter the resulting color. (#2050)
- Misc: Added optional misc/stl/imgui_stl.h wrapper to use with STL types (e.g. InputText with std::string). (#2006, #1443, #1008)
  [*EDIT* renamed to misc/std/imgui_stdlib.h in 1.66]
- Misc: Added IMGUI_VERSION_NUM for easy compile-time testing. (#2025)
- Misc: Added ImGuiMouseCursor_Hand cursor enum + corresponding software cursor. (#1913, 1914) [@aiekick, @ocornut]
- Misc: Tweaked software mouse cursor offset to match the offset of the corresponding Windows 10 cursors.
- Made assertion more clear when trying to call Begin() outside of the NewFrame()..EndFrame() scope. (#1987)
- Fixed assertion when transitioning from an active ID to another within a group, affecting ColorPicker (broken in 1.62). (#2023, #820, #956, #1875).
- Fixed PushID() from keeping alive the new ID Stack top value (if a previously active widget shared the ID it would be erroneously kept alive).
- Fixed horizontal mouse wheel not forwarding the request to the parent window if ImGuiWindowFlags_NoScrollWithMouse is set. (#1463, #1380, #1502)
- Fixed a include build issue for Cygwin in non-POSIX (Win32) mode. (#1917, #1319, #276)
- ImDrawList: Improved handling for worst-case vertices reservation policy when large amount of text (e.g. 1+ million character strings)
  are being submitted in a single call. It would typically have crashed InputTextMultiline(). (#200)
- OS/Windows: Fixed missing ImmReleaseContext() call in the default Win32 IME handler. (#1932) [@vby]
- Metrics: Changed io.MetricsActiveWindows to reflect the number of active windows (!= from visible windows), which is useful
  for lazy/idle render mechanisms as new windows are typically not visible for one frame.
- Metrics: Added io.MetricsRenderWindow to reflect the number of visible windows.
- Metrics: Added io.MetricsActiveAllocations, moving away from the cross-context global counters than we previously used. (#1565, #1599, #586)
- Demo: Added basic Drag and Drop demo. (#143)
- Demo: Modified the Console example to use InsertChars() in the input text callback instead of poking directly into the buffer.
  Although this won't make a difference in the example itself, using InsertChars() will honor the resizing callback properly. (#2006, #1443, #1008).
- Demo: Clarified the use of IsItemHovered()/IsItemActive() right after being in the "Active, Focused, Hovered & Focused Tests" section.
- Examples: Tweaked the main.cpp of each example.
- Examples: Metal: Added Metal rendering backend. (#1929, #1873) [@warrenm]
- Examples: OSX: Added early raw OSX platform backend. (#1873) [@pagghiu, @itamago, @ocornut]
- Examples: Added mac OSX & iOS + Metal example in example_apple_metal/. (#1929, #1873) [@warrenm]
- Examples: Added mac OSX + OpenGL2 example in example_apple_opengl2/. (#1873)
- Examples: OpenGL3: Added shaders more versions of GLSL. (#1938, #1941, #1900, #1513, #1466, etc.)
- Examples: OpenGL3: Tweaked the imgui_impl_opengl3.cpp to work as-is with Emscripten + WebGL 2.0. (#1941). [@o-micron]
- Examples: OpenGL3: Made the example app default to GL 3.0 + GLSL 130 (instead of GL 3.2 + GLSL 150) unless on Mac.
- Examples: OpenGL3: Added error output when shaders fail to compile/link.
- Examples: OpenGL3: Added support for glew and glad OpenGL loaders out of the box. (#2001, #2002) [@jdumas]
- Examples: OpenGL2: Disabling/restoring GL_LIGHTING and GL_COLOR_MATERIAL to increase compatibility with legacy OpenGL applications. (#1996)
- Examples: DirectX10, DirectX11: Fixed unreleased resources in Init and Shutdown functions. (#1944)
- Examples: DirectX11: Querying for IDXGIFactory instead of IDXGIFactory1 to increase compatibility. (#1989) [@matt77hias]
- Examples: Vulkan: Fixed handling of VkSurfaceCapabilitiesKHR::maxImageCount = 0 case. Tweaked present mode selections.
- Examples: Win32, Glfw, SDL: Added support for the ImGuiMouseCursor_Hand cursor.


-----------------------------------------------------------------------
 VERSION 1.62 (Released 2018-06-22)
-----------------------------------------------------------------------

Decorated log: https://github.com/ocornut/imgui/releases/tag/v1.62

Breaking Changes:

- TreeNodeEx(): The helper ImGuiTreeNodeFlags_CollapsingHeader flag now include ImGuiTreeNodeFlags_NoTreePushOnOpen.
  The flag was already set by CollapsingHeader().
  The only difference is if you were using TreeNodeEx() manually with ImGuiTreeNodeFlags_CollapsingHeader and without
  ImGuiTreeNodeFlags_NoTreePushOnOpen. In this case you can remove the ImGuiTreeNodeFlags_NoTreePushOnOpen flag from
  your call (ImGuiTreeNodeFlags_CollapsingHeader & ~ImGuiTreeNodeFlags_NoTreePushOnOpen). (#1864)
  This also apply if you were using internal's TreeNodeBehavior() with the ImGuiTreeNodeFlags_CollapsingHeader flag directly.
- ImFontAtlas: Renamed GetGlyphRangesChinese() to GetGlyphRangesChineseFull() to distinguish new smaller variants and
  discourage using the full set. (#1859)

Other Changes:

- Examples backends have been refactored to separate the platform code (e.g. Win32, Glfw, SDL2) from the renderer code (e.g. DirectX11, OpenGL3, Vulkan).
  The "Platform" backends are in charge of: mouse/keyboard/gamepad inputs, cursor shape, timing, etc.
  The "Renderer" backends are in charge of: creating the main font texture, rendering imgui draw data.
      before: imgui_impl_dx11.cpp        --> after: imgui_impl_win32.cpp + imgui_impl_dx11.cpp
      before: imgui_impl_dx12.cpp        --> after: imgui_impl_win32.cpp + imgui_impl_dx12.cpp
      before: imgui_impl_glfw_gl3.cpp    --> after: imgui_impl_glfw.cpp + imgui_impl_opengl2.cpp
      before: imgui_impl_glfw_vulkan.cpp --> after: imgui_impl_glfw.cpp + imgui_impl_vulkan.cpp
      before: imgui_impl_sdl_gl3.cpp     --> after: imgui_impl_sdl2.cpp + imgui_impl_opengl2.cpp
      before: imgui_impl_sdl_gl3.cpp     --> after: imgui_impl_sdl2.cpp + imgui_impl_opengl3.cpp etc.
  - The idea is what we can now easily combine and maintain backends and reduce code redundancy. Individual files are
    smaller and more reusable. Integration of imgui into a new/custom engine may also be easier as there is less overlap
    between "windowing / inputs" and "rendering" code, so you may study or grab one half of the code and not the other.
  - This change was motivated by the fact that adding support for the upcoming multi-viewport feature requires more work
    from the Platform and Renderer backends, and the amount of redundancy across files was becoming too difficult to
    maintain. If you use default backends, you'll benefit from an easy update path to support multi-viewports later
    (for future ImGui 1.7x).
  - This is not strictly a breaking change if you keep your old backends, but when you'll want to fully update your backends,
    expect to have to reshuffle a few things.
  - Each example still has its own main.cpp which you may refer you to understand how to initialize and glue everything together.
  - Some frameworks (such as the Allegro, Marmalade) handle both the "platform" and "rendering" part, and your custom engine may as well.
  - Read examples/README.txt for details.
- Added IsItemDeactivated() to query if the last item was active previously and isn't anymore. Useful for Undo/Redo patterns. (#820, #956, #1875)
- Added IsItemDeactivatedAfterChange() [*EDIT* renamed to IsItemDeactivatedAfterEdit() in 1.63] if the last item was active previously,
  is not anymore, and during its active state modified a value. Note that you may still get false positive (e.g. drag value and while
  holding return on the same value). (#820, #956, #1875)
- Nav: Added support for PageUp/PageDown (explorer-style: first aim at bottom/top most item, when scroll a page worth of contents). (#787)
- Nav: To keep the navigated item in view we also attempt to scroll the parent window as well as the current window. (#787)
- ColorEdit3, ColorEdit4, ColorButton: Added ImGuiColorEditFlags_NoDragDrop flag to disable ColorEditX as drag target and ColorButton as drag source. (#1826)
- BeginDragDropSource(): Offset tooltip position so it is off the mouse cursor, but also closer to it than regular tooltips,
  and not clamped by viewport. (#1739)
- BeginDragDropTarget(): Added ImGuiDragDropFlags_AcceptNoPreviewTooltip flag to request hiding the drag source tooltip
  from the target site. (#143)
- BeginCombo(), BeginMainMenuBar(), BeginChildFrame(): Temporary style modification are restored at the end of BeginXXX
  instead of EndXXX, to not affect tooltips and child windows.
- Popup: Improved handling of (erroneously) repeating calls to OpenPopup() to not close the popup's child popups. (#1497, #1533, #1865).
- InputTextMultiline(): Fixed double navigation highlight when scrollbar is active. (#787)
- InputText(): Fixed Undo corruption after pasting large amount of text (Redo will still fail when undo buffers are exhausted,
  but text won't be corrupted).
- SliderFloat(): When using keyboard/gamepad and a zero precision format string (e.g. "%.0f"), always step in integer units. (#1866)
- ImFontConfig: Added GlyphMinAdvanceX/GlyphMaxAdvanceX settings useful to make a font appears monospaced, particularly useful
  for icon fonts. (#1869)
- ImFontAtlas: Added GetGlyphRangesChineseSimplifiedCommon() helper that returns a list of ~2500 most common Simplified Chinese
  characters. (#1859) [@JX-Master, @ocornut]
- Examples: OSX: Added imgui_impl_osx.mm backend to be used along with e.g. imgui_impl_opengl2.cpp. (#281, #1870) [@pagghiu, @itamago, @ocornut]
- Examples: GLFW: Made it possible to Shutdown/Init the backend again (by resetting the time storage properly). (#1827) [@ice1000]
- Examples: Win32: Fixed handling of mouse wheel messages to support sub-unit scrolling messages (typically sent by track-pads). (#1874) [@zx64]
- Examples: SDL+Vulkan: Added SDL+Vulkan example.
- Examples: Allegro5: Added support for ImGuiConfigFlags_NoMouseCursorChange flag. Added clipboard support.
- Examples: Allegro5: Unindexing buffers ourselves as Allegro indexed drawing primitives are buggy in the DirectX9 backend
  (will be fixed in Allegro 5.2.5+).
- Examples: DirectX12: Moved the ID3D12GraphicsCommandList* parameter from ImGui_ImplDX12_NewFrame() to ImGui_ImplDX12_RenderDrawData() which makes a lots more sense. (#301)
- Examples: Vulkan: Reordered parameters ImGui_ImplVulkan_RenderDrawData() to be consistent with other backends,
  a good occasion since we refactored the code.
- Examples: FreeGLUT: Added FreeGLUT backends. Added FreeGLUT+OpenGL2 example. (#801)
- Examples: The functions in imgui_impl_xxx.cpp are prefixed with IMGUI_IMPL_API (which defaults to IMGUI_API) to facilitate
  some uses. (#1888)
- Examples: Fixed backends to use ImGuiMouseCursor_COUNT instead of old name ImGuiMouseCursor_Count_ so they can compile
  with IMGUI_DISABLE_OBSOLETE_FUNCTIONS. (#1887)
- Misc: Updated stb_textedit from 1.09 + patches to 1.12 + minor patches.
- Internals: PushItemFlag() flags are inherited by BeginChild().


-----------------------------------------------------------------------
 VERSION 1.61 (Released 2018-05-14)
-----------------------------------------------------------------------

Decorated log: https://github.com/ocornut/imgui/releases/tag/v1.61

Breaking Changes:

- DragInt(): The default compile-time format string has been changed from "%.0f" to "%d", as we are not using integers internally
  any more. If you used DragInt() with custom format strings, make sure you change them to use %d or an integer-compatible format.
  To honor backward-compatibility, the DragInt() code will currently parse and modify format strings to replace %*f with %d,
  giving time to users to upgrade their code.
  If you have IMGUI_DISABLE_OBSOLETE_FUNCTIONS enabled, the code will instead assert! You may run a reg-exp search on your
  codebase for e.g. "DragInt.*%f" to you find them.
- InputFloat(): Obsoleted InputFloat() functions taking an optional "int decimal_precision" in favor of an equivalent and more
  flexible "const char* format", consistent with other functions. Kept redirection functions (will obsolete).
- Misc: IM_DELETE() helper function added in 1.60 doesn't set the input pointer to NULL, more consistent with standard
  expectation and allows passing r-values.

Other Changes:

- Added DragScalar, DragScalarN: supports signed/unsigned, 32/64 bits, float/double data types. (#643, #320, #708, #1011)
- Added InputScalar, InputScalarN: supports signed/unsigned, 32/64 bits, float/double data types. (#643, #320, #708, #1011)
- Added SliderScalar, SliderScalarN: supports signed/unsigned, 32/64 bits, float/double data types. (#643, #320, #708, #1011)
- Window: Fixed pop-ups/tooltips/menus not honoring style.DisplaySafeAreaPadding as well as it should have (part of menus
  displayed outside the safe area, etc.).
- Window: Fixed windows using the ImGuiWindowFlags_NoSavedSettings flag from not using the same default position as other windows. (#1760)
- Window: Relaxed the internal stack size checker to allow Push/Begin/Pop/.../End patterns to be used with PushStyleColor, PushStyleVar, PushFont without causing a false positive assert. (#1767)
- Window: Fixed the default proportional item width lagging by one frame on resize.
- Columns: Fixed a bug introduced in 1.51 where columns would affect the contents size of their container, often creating
  feedback loops when ImGuiWindowFlags_AlwaysAutoResize was used. (#1760)
- Settings: Fixed saving an empty .ini file if CreateContext/DestroyContext are called without a single call to NewFrame(). (#1741)
- Settings: Added LoadIniSettingsFromDisk(), LoadIniSettingsFromMemory(), SaveIniSettingsToDisk(), SaveIniSettingsToMemory()
  to manually load/save .ini settings. (#923, #993)
- Settings: Added io.WantSaveIniSettings flag, which is set to notify the application that e.g. SaveIniSettingsToMemory()
  should be called. (#923, #993)
- Scrolling: Fixed a case where using SetScrollHere(1.0f) at the bottom of a window on the same frame the window height
  has been growing would have the scroll clamped using the previous height. (#1804)
- MenuBar: Made BeginMainMenuBar() honor style.DisplaySafeAreaPadding so the text can be made visible on TV settings that
  don't display all pixels. (#1439) [@dougbinks]
- InputText: On Mac OS X, filter out characters when the CMD modifier is held. (#1747) [@sivu]
- InputText: On Mac OS X, support CMD+SHIFT+Z for Redo. CMD+Y is also supported as major apps seems to default to support both. (#1765) [@lfnoise]
- InputText: Fixed returning true when edition is cancelled with ESC and the current buffer matches the initial value.
- InputFloat,InputFloat2,InputFloat3,InputFloat4: Added variations taking a more flexible and consistent optional
  "const char* format" parameter instead of "int decimal_precision". This allow using custom formats to display values
  in scientific notation, and is generally more consistent with other API.
  Obsoleted functions using the optional "int decimal_precision" parameter. (#648, #712)
- DragFloat, DragInt: Cancel mouse tweak when current value is initially past the min/max boundaries and mouse is pushing
  in the same direction (keyboard/gamepad version already did this).
- DragFloat, DragInt: Honor natural type limits (e.g. INT_MAX, FLT_MAX) instead of wrapping around. (#708, #320)
- DragFloat, SliderFloat: Fixes to allow input of scientific notation numbers when using CTRL+Click to input the value. (~#648, #1011)
- DragFloat, SliderFloat: Rounding-on-write uses the provided format string instead of parsing the precision from the string,
  which allows for finer uses of %e %g etc. (#648, #642)
- DragFloat: Improved computation when using the power curve. Improved lost of input precision with very small steps.
  Added an assert than power-curve requires a min/max range. (~#642)
- DragFloat: The 'power' parameter is only honored if the min/max parameter are also setup.
- DragInt, SliderInt: Fixed handling of large integers (we previously passed data around internally as float, which reduced
  the range of valid integers).
- ColorEdit: Fixed not being able to pass the ImGuiColorEditFlags_NoAlpha or ImGuiColorEditFlags_HDR flags to SetColorEditOptions().
- Nav: Fixed hovering a Selectable() with the mouse so that it update the navigation cursor (as it happened in the pre-1.60 navigation branch). (#787)
- Style: Changed default style.DisplaySafeAreaPadding values from (4,4) to (3,3) so it is smaller than FramePadding and has no effect on main menu bar on a computer. (#1439)
- Fonts: When building font atlas, glyphs that are missing in the fonts are not using the glyph slot to render the default glyph. Saves space and allow merging fonts with
  overlapping font ranges such as FontAwesome5 which split out the Brands separately from the Solid fonts. (#1703, #1671)
- Misc: Added IMGUI_CHECKVERSION() macro to compare version string and data structure sizes in order to catch issues with mismatching compilation unit settings. (#1695, #1769)
- Misc: Added IMGUI_DISABLE_MATH_FUNCTIONS in imconfig.h to make it easier to redefine wrappers for std/crt math functions.
- Misc: Fix to allow compiling in unity builds where stb_rectpack/stb_truetype may be already included in the same compilation unit.
- Demo: Simple Overlay: Added a context menu item to enable freely moving the window.
- Demo: Added demo for DragScalar(), InputScalar(), SliderScalar(). (#643)
- Examples: Calling IMGUI_CHECKVERSION() in the main.cpp of every example application.
- Examples: Allegro 5: Added support for 32-bit indices setup via defining ImDrawIdx, to avoid an unnecessary conversion (Allegro 5 doesn't support 16-bit indices).
- Examples: Allegro 5: Renamed backend from imgui_impl_a5.cpp to imgui_impl_allegro5.cpp.
- Examples: DirectX 9: Saving/restoring Transform because they don't seem to be included in the StateBlock. Setting shading mode to Gouraud. (#1790, #1687) [@sr-tream]
- Examples: SDL: Fixed clipboard paste memory leak in the SDL backend code. (#1803) [@eliasdaler]
- Various minor fixes, tweaks, refactoring, comments.


-----------------------------------------------------------------------
 VERSION 1.60 (Released 2018-04-07)
-----------------------------------------------------------------------

Decorated log: https://github.com/ocornut/imgui/releases/tag/v1.60

The gamepad/keyboard navigation branch (which has been in the work since July 2016) has been merged.
Gamepad/keyboard navigation is still marked as Beta and has to be enabled explicitly.
Various internal refactoring have also been done, as part of the navigation work and as part of the upcoming viewport/docking work.

Breaking Changes:

- Obsoleted the io.RenderDrawListsFn callback, you can call your graphics engine render function after ImGui::Render().
  e.g. with example backends, call ImDrawData* draw_data = ImGui::GetDrawData(); ImGui_ImplXXXX_RenderDrawData(draw_data).
- Reorganized context handling to be more explicit: (#1599)
  - YOU NOW NEED TO CALL ImGui::CreateContext() AT THE BEGINNING OF YOUR APP, AND CALL ImGui::DestroyContext() AT THE END.
  - removed Shutdown() function, as DestroyContext() serve this purpose. If you are using an old backend from the examples/ folder, remove the line that calls Shutdown().
  - you may pass a ImFontAtlas* pointer to CreateContext() to share a font atlas between contexts. Otherwise CreateContext() will create its own font atlas instance.
  - removed allocator parameters from CreateContext(), they are now setup with SetAllocatorFunctions(), and shared by all contexts.
  - removed the default global context and font atlas instance, which were confusing for users of DLL reloading and users of multiple contexts.
- Renamed ImGuiStyleVar_Count_ to ImGuiStyleVar_COUNT and ImGuiMouseCursor_Count_ to ImGuiMouseCursor_COUNT for consistency with other public enums.
- Fonts: Moved sample TTF files from extra_fonts/ to misc/fonts/. If you loaded files directly from the imgui repo you may need to update your paths.
- Fonts: Changed ImFont::DisplayOffset.y to defaults to 0 instead of +1. Fixed vertical rounding of Ascent/Descent to match TrueType renderer.
  If you were adding or subtracting (not assigning) to ImFont::DisplayOffset check if your fonts are correctly aligned vertically. (#1619)
- BeginDragDropSource(): temporarily removed the optional mouse_button=0 parameter because it is not really usable in many situations at the moment.
- Obsoleted IsAnyWindowHovered() in favor of IsWindowHovered(ImGuiHoveredFlags_AnyWindow). Kept redirection function (will obsolete).
- Obsoleted IsAnyWindowFocused() in favor of IsWindowFocused(ImGuiFocusedFlags_AnyWindow). Kept redirection function (will obsolete).
- Renamed io.WantMoveMouse to io.WantSetMousePos for consistency and ease of understanding (was added in 1.52, not used by core, and honored by some backend ahead of merging the Nav branch).
- Removed ImGuiCol_CloseButton, ImGuiCol_CloseButtonActive, ImGuiCol_CloseButtonHovered style colors as the closing cross uses regular button colors now.
- Renamed ImGuiSizeConstraintCallback to ImGuiSizeCallback, ImGuiSizeConstraintCallbackData to ImGuiSizeCallbackData.
- Removed CalcItemRectClosestPoint() which was weird and not really used by anyone except demo code. If you need it should be easy to replicate on your side (you can find the code in 1.53).
- [EDITED] Window: BeginChild() with an explicit name doesn't include the hash within the internal window name. (#1698)
  This change was erroneously introduced, undoing the change done for #894, #713, and not documented properly in the original
  1.60 release Changelog. It was fixed on 2018-09-28 (1.66) and I wrote this paragraph the same day.

Other Changes:

- Doc: Added a Changelog file in the repository to ease comparing versions (it goes back to dear imgui 1.48), until now it was only on GitHub.
- Navigation: merged in the gamepad/keyboard navigation (about a million changes!). (#787, #323)
  The initial focus was to support game controllers, but keyboard is becoming increasingly and decently usable.
- To use Gamepad Navigation:
  - Set io.ConfigFlags |= ImGuiConfigFlags_NavEnableGamepad to enable.
  - Backend: Set io.BackendFlags |= ImGuiBackendFlags_HasGamepad + fill the io.NavInputs[] fields before calling NewFrame(). Read imgui.cpp for more details.
  - See https://github.com/ocornut/imgui/issues/1599 for recommended gamepad mapping or download PNG/PSD at http://goo.gl/9LgVZW
  - See 'enum ImGuiNavInput_' in imgui.h for a description of inputs. Read imgui.cpp for more details.
- To use Keyboard Navigation:
  - Set io.ConfigFlags |= ImGuiConfigFlags_NavEnableKeyboard to enable. NewFrame() will automatically fill io.NavInputs[] based on your io.KeysDown[] + io.KeyMap[] arrays.
  - Basic controls: arrows to navigate, Alt to enter menus, Space to activate item, Enter to edit text, Escape to cancel/close, Ctrl-Tab to focus windows, etc.
  - When keyboard navigation is active (io.NavActive + ImGuiConfigFlags_NavEnableKeyboard), the io.WantCaptureKeyboard flag will be set.
    For more advanced uses, you may want to read from io.NavActive or io.NavVisible. Read imgui.cpp for more details.
- Navigation: SetItemDefaultFocus() sets the navigation position in addition to scrolling. (#787)
- Navigation: Added IsItemFocused(), added IsAnyItemFocused(). (#787)
- Navigation: Added window flags: ImGuiWindowFlags_NoNav (== ImGuiWindowFlags_NoNavInputs | ImGuiWindowFlags_NoNavFocus).
- Navigation: Style: Added ImGuiCol_NavHighlight, ImGuiCol_NavWindowingHighlight colors. (#787)
- Navigation: TreeNode: Added ImGuiTreeNodeFlags_NavLeftJumpsBackHere flag to allow Nav Left direction to jump back to parent tree node from any of its child. (#1079)
- Navigation: IO: Added io.ConfigFlags (input), io.NavActive (output), io.NavVisible (output). (#787)
- Context: Removed the default global context and font atlas instances, which caused various problems to users of multiple contexts and DLL users. (#1565, #1599)
  YOU NOW NEED TO CALL ImGui::CreateContext() AT THE BEGINNING OF YOUR APP, AND CALL ImGui::DestroyContext() AT THE END. Existing apps will assert/crash without it.
- Context: Added SetAllocatorFunctions() to rewire memory allocators (as a replacement to previous parameters to CreateContext()). Allocators are shared by all contexts and imgui helpers. (#1565, #586, #992, #1007, #1558)
- Context: You may pass a ImFontAtlas to CreateContext() to specify a font atlas to share. Shared font atlas are not owned by the context and not destroyed along with it. (#1599)
- Context: Added IMGUI_DISABLE_DEFAULT_ALLOCATORS to disable linking with malloc/free. (#1565, #586, #992, #1007, #1558)
- IO: Added io.ConfigFlags for user application to store settings for imgui and for the backend:
  - ImGuiConfigFlags_NavEnableKeyboard: Enable keyboard navigation.
  - ImGuiConfigFlags_NavEnableGamepad: Enable gamepad navigation (provided ImGuiBackendFlags_HasGamepad is also set by backend).
  - ImGuiConfigFlags_NavEnableSetMousePos: Instruct navigation to move the mouse cursor. May be useful on TV/console systems where moving a virtual mouse is awkward.
  - ImGuiConfigFlags_NoMouseCursorChange: Instruct backend to not alter mouse cursor shape and visibility (by default the example backend use mouse cursor API of the platform when available)
  - ImGuiConfigFlags_NoMouse: Instruct imgui to clear mouse position/buttons in NewFrame(). This allows ignoring the mouse information passed by the backend.
  - ImGuiConfigFlags_IsSRGB, ImGuiConfigFlags_IsTouchScreen: Flags for general application use.
- IO: Added io.BackendFlags for backend to store its capabilities (currently: _HasGamepad, _HasMouseCursors, _HasSetMousePos). This will be used more in the next version.
- IO: Added ImGuiKey_Insert, ImGuiKey_Space keys. Setup in all example backends. (#1541)
- IO: Added Horizontal Mouse Wheel support for horizontal scrolling. (#1463) [@tseeker]
- IO: Added IsAnyMouseDown() helper which is helpful for backends to handle mouse capturing.
- Window: Clicking on a window with the ImGuiWIndowFlags_NoMove flags takes an ActiveId so we can't hover something else when dragging afterwards. (#1381, #1337)
- Window: IsWindowHovered(): Added ImGuiHoveredFlags_AnyWindow, ImGuiFocusedFlags_AnyWindow flags (See Breaking Changes). Added to demo. (#1382)
- Window: Added SetNextWindowBgAlpha() helper. Particularly helpful since the legacy 5-parameters version of Begin() has been marked as obsolete in 1.53. (#1567)
- Window: Fixed SetNextWindowContentSize() with 0.0f on Y axis (or SetNextWindowContentWidth()) overwriting the contents size. Got broken on Dec 10 (1.53). (#1363)
- ArrowButton: Added ArrowButton() given a cardinal direction (e.g. ImGuiDir_Left).
- InputText: Added alternative clipboard shortcuts: Shift+Delete (cut), CTRL+Insert (copy), Shift+Insert (paste). (#1541)
- InputText: Fixed losing Cursor X position when clicking outside on an item that's submitted after the InputText(). It was only noticeable when restoring focus programmatically. (#1418, #1554)
- InputText: Added ImGuiInputTextFlags_CharsScientific flag to also allow 'e'/'E' for input of values using scientific notation. Automatically used by InputFloat.
- Style: Default style is now StyleColorsDark(), instead of the old StyleColorsClassic(). (#707)
- Style: Enable window border by default. (#707)
- Style: Exposed ImGuiStyleVar_WindowTitleAlign, ImGuiStyleVar_ScrollbarSize, ImGuiStyleVar_ScrollbarRounding, ImGuiStyleVar_GrabRounding + added an assert to reduce accidental breakage. (#1181)
- Style: Added style.MouseCursorScale help when using the software mouse cursor facility. (#939).
- Style: Close button nows display a cross before hovering. Fixed cross positioning being a little off. Uses button colors for highlight when hovering. (#707)
- Popup: OpenPopup() Always reopen existing pop-ups. (Removed imgui_internal.h's OpenPopupEx() which was used for this.) (#1497, #1533).
- Popup: BeginPopupContextItem(), BeginPopupContextWindow(), BeginPopupContextVoid(), OpenPopupOnItemClick() all react on mouse release instead of mouse press. (~#439)
- Popup: Better handling of user mistakenly calling OpenPopup() every frame (with reopen_existing option). The error will now be more visible and easier to understand. (#1497)
- Popup: BeginPopup(): Exposed extra_flags parameter that are passed through to Begin(). (#1533)
- Popup: BeginPopupModal: fixed the conditional test for SetNextWindowPos() which was polling the wrong window, which in practice made the test succeed all the time.
- Tooltip: BeginTooltip() sets ImGuiWindowFlags_NoInputs flag.
- Scrollbar: Fixed ScrollbarY enable test after ScrollbarX has been enabled being a little off (small regression from Nov 2017). (#1574)
- Scrollbar: Fixed ScrollbarX enable test subtracting WindowPadding.x (this has been there since the addition of horizontal scroll bar!).
- Columns: Clear offsets data when columns count changed. (#1525)
- Columns: Fixed a memory leak of ImGuiColumnsSet's Columns vector. (#1529) [@unprompted]
- Columns: Fixed resizing a window very small breaking some columns positioning (broken in 1.53).
- Columns: The available column extent takes consideration of the right-most clipped pixel, so the right-most column may look a little wider but will contain the same amount of visible contents.
- MenuBar: Fixed menu bar pushing a clipping rect outside of its allocated bound (usually unnoticeable).
- TreeNode: nodes with the ImGuiTreeNodeFlags_Leaf flag correctly disable highlight when DragDrop is active. (#143, #581)
- Drag and Drop: Increased payload type string to 32 characters instead of 8. (#143)
- Drag and Drop: TreeNode as drop target displays rectangle over full frame. (#1597, #143)
- DragFloat: Fix/workaround for backends which do not preserve a valid mouse position when dragged out of bounds. (#1559)
- InputFloat: Allow inputing value using scientific notation e.g. "1e+10".
- InputDouble: Added InputDouble() function. We use a format string instead of a decimal_precision parameter to also for "%e" and variants. (#1011)
- Slider, Combo: Use ImGuiCol_FrameBgHovered color when hovered. (#1456) [@stfx]
- Combo: BeginCombo(): Added ImGuiComboFlags_NoArrowButton to disable the arrow button and only display the wide value preview box.
- Combo: BeginCombo(): Added ImGuiComboFlags_NoPreview to disable the preview and only display a square arrow button.
- Combo: Arrow button isn't displayed over frame background so its blended color matches other buttons. Left side of the button isn't rounded.
- PlotLines: plot a flat line if scale_min==scale_max. (#1621)
- Fonts: Changed DisplayOffset.y to defaults to 0 instead of +1. Fixed rounding of Ascent/Descent to match TrueType renderer.
  If you were adding or subtracting (not assigning) to ImFont::DisplayOffset check if your fonts are correctly aligned vertically. (#1619)
- Fonts: Updated stb_truetype from 1.14 to stb_truetype 1.19. (w/ include fix from some platforms #1622)
- Fonts: Added optional FreeType rasterizer in misc/freetype. Moved from imgui_club repo. (#618) [@Vuhdo, @mikesart, @ocornut]
- Fonts: Moved extra_fonts/ to misc/fonts/.
- ImFontAtlas: Fixed cfg.MergeMode not reusing existing glyphs if available (always overwrote).
- ImFontAtlas: Handle stb_truetype stbtt_InitFont() and stbtt_PackBegin() possible failures more gracefully, GetTexDataAsRGBA32() won't crash during conversion. (#1527)
- ImFontAtlas: Moved mouse cursor data out of ImGuiContext, fix drawing them with multiple contexts. Also remove the last remaining undesirable dependency on ImGui in imgui_draw.cpp. (#939)
- ImFontAtlas: Added ImFontAtlasFlags_NoPowerOfTwoHeight flag to disable padding font height to nearest power of two. (#1613)
- ImFontAtlas: Added ImFontAtlasFlags_NoMouseCursors flag to disable baking software mouse cursors, mostly to save texture memory on very low end hardware. (#1613)
- ImDrawList: Fixed AddRect() with anti-aliasing disabled (lower-right corner pixel was often missing, rounding looks a little better.) (#1646)
- ImDrawList: Added CloneOutput() helper to facilitate the cloning of ImDrawData or ImDrawList for multi-threaded rendering.
- Misc: Functions passed to libc qsort are explicitly marked cdecl to support compiling with vectorcall as the default calling convention. (#1230, #1611) [@RandyGaul]
- Misc: ImVec2: added [] operator. This is becoming desirable for some code working of either axes independently. Better adding it sooner than later.
- Misc: NewFrame(): Added an assert to detect incorrect filling of the io.KeyMap[] array earlier. (#1555)
- Misc: Added IM_OFFSETOF() helper in imgui.h (previously was in imgui_internal.h)
- Misc: Added IM_NEW(), IM_DELETE() helpers in imgui.h (previously were in imgui_internal.h)
- Misc: Added obsolete redirection function GetItemsLineHeightWithSpacing() (which redirects to GetFrameHeightWithSpacing()), as intended and stated in docs of 1.53.
- Misc: Added misc/natvis/imgui.natvis for visual studio debugger users to easily visualize imgui internal types. Added to examples projects.
- Misc: Added IMGUI_USER_CONFIG to define a custom configuration filename. (#255, #1573, #1144, #41)
- Misc: Added IMGUI_STB_TRUETYPE_FILENAME and IMGUI_STB_RECT_PACK_FILENAME compile time directives to use another version of the stb_ files.
- Misc: Updated stb_rect_pack from 0.10 to 0.11 (minor changes).
  (Those flags are not used by ImGui itself, they only exists to make it easy for the engine/backend to pass information to the application in a standard manner.)
- Metrics: Added display of Columns state.
- Demo: Improved Selectable() examples. (#1528)
- Demo: Tweaked the Child demos, added a menu bar to the second child to test some navigation functions.
- Demo: Console: Using ImGuiCol_Text to be more friendly to color changes.
- Demo: Using IM_COL32() instead of ImColor() in ImDrawList centric contexts. Trying to phase out use of the ImColor helper whenever possible.
- Examples: Files in examples/ now include their own changelog so it is easier to occasionally update your backends if needed.
- Examples: Using Dark theme by default. (#707). Tweaked demo code.
- Examples: Added support for horizontal mouse wheel for API that allows it. (#1463) [@tseeker]
- Examples: All examples now setup the io.BackendFlags to signify they can honor mouse cursors, gamepad, etc.
- Examples: DirectX10: Fixed erroneous call to io.Fonts->ClearInputData() + ClearTexData() that was left in DX10 example but removed in 1.47 (Nov 2015) in every other backends. (#1733)
- Examples: DirectX12: Added DirectX 12 example. (#301) [@jdm3]
- Examples: OpenGL3+GLFW,SDL: Changed GLSL shader version from 330 to 150. (#1466, #1504)
- Examples: OpenGL3+GLFW,SDL: Added a way to override the GLSL version string in the Init function. (#1466, #1504).
- Examples: OpenGL3+GLFW,SDL: Creating VAO in the render function so it can be more easily used by multiple shared OpenGL contexts. (#1217)
- Examples: OpenGL3+GLFW: Using 3.2 context instead of 3.3. (#1466)
- Examples: OpenGL: Setting up glPixelStorei() explicitly before uploading texture.
- Examples: OpenGL: Calls to glPolygonMode() are casting parameters as GLEnum to not fail with more strict backends. (#1628) [@ilia-glushchenko]
- Examples: Win32 (DirectX9,10,11,12): Added support for mouse cursor shapes. (#1495)
- Examples: Win32 (DirectX9,10,11,12: Support for windows using the CS_DBLCLKS class flag by handling the double-click messages (WM_LBUTTONDBLCLK etc.). (#1538, #754) [@ndandoulakis]
- Examples: Win32 (DirectX9,10,11,12): Made the Win32 proc handlers not assert if there is no active context yet, to be more flexible with creation order. (#1565)
- Examples: GLFW: Added support for mouse cursor shapes (the diagonal resize cursors are unfortunately not supported by GLFW at the moment. (#1495)
- Examples: GLFW: Don't attempt to change the mouse cursor input mode if it is set to GLFW_CURSOR_DISABLED by the application. (#1202) [@PhilCK]
- Examples: SDL: Added support for mouse cursor shapes. (#1626) [@olls]
- Examples: SDL: Using SDL_CaptureMouse() to retrieve coordinates outside of client area when dragging (SDL 2.0.4+ only, otherwise using SDL_WINDOW_INPUT_FOCUS instead of previously SDL_WINDOW_MOUSE_FOCUS). (#1559)
- Examples: SDL: Enabled vsync by default so people don't come at us when the examples are running at 2000 FPS and burning a CPU core.
- Examples: SDL: Using SDL_GetPerformanceCounter() / SDL_GetPerformanceFrequency() to handle frame-rate over 1000 FPS properly. (#996)
- Examples: SDL: Using scan-code exclusively instead of a confusing mixture of scan-codes and key-codes.
- Examples: SDL: Visual Studio: Added .vcxproj file. Using %SDL2_DIR% in the default .vcxproj and build files instead of %SDL_DIR%, the earlier being more standard.
- Examples: Vulkan: Visual Studio: Added .vcxproj file.
- Examples: Apple: Fixed filenames in OSX xcode project. Various other Mac friendly fixes. [@gerryhernandez etc.]
- Examples: Visual Studio: Disabled extraneous function-level check in Release build.
- Various fixes, tweaks, internal refactoring, optimizations, comments.


-----------------------------------------------------------------------
 VERSION 1.53 (Released 2017-12-25)
-----------------------------------------------------------------------

Decorated log: https://github.com/ocornut/imgui/releases/tag/v1.53

Breaking Changes:

- Renamed the emblematic `ShowTestWindow()` function to `ShowDemoWindow()`. Kept redirection function (will obsolete).
- Renamed `GetItemsLineHeightWithSpacing()` to `GetFrameHeightWithSpacing()` for consistency. Kept redirection function (will obsolete).
- Renamed `ImGuiTreeNodeFlags_AllowOverlapMode` flag to `ImGuiTreeNodeFlags_AllowItemOverlap`. Kept redirection enum (will obsolete).
- Obsoleted `IsRootWindowFocused()` in favor of using `IsWindowFocused(ImGuiFocusedFlags_RootWindow)`. Kept redirection function (will obsolete). (#1382)
- Obsoleted `IsRootWindowOrAnyChildFocused()` in favor of using `IsWindowFocused(ImGuiFocusedFlags_RootAndChildWindows)`. Kept redirection function (will obsolete). (#1382)
- Obsoleted `IsRootWindowOrAnyChildHovered()` in favor of using `IsWindowHovered(ImGuiHoveredFlags_RootAndChildWindows)`. Kept redirection function (will obsolete). (#1382)
- Obsoleted `SetNextWindowContentWidth() in favor of using `SetNextWindowContentSize()`. Kept redirection function (will obsolete).
- Renamed `ImGuiTextBuffer::append()` helper to `appendf()`, and `appendv()` to `appendfv()` for consistency. If you copied the 'Log' demo in your code, it uses appendv() so that needs to be renamed.
- ImDrawList: Removed 'bool anti_aliased = true' final parameter of `ImDrawList::AddPolyline()` and `ImDrawList::AddConvexPolyFilled()`. Prefer manipulating ImDrawList::Flags if you need to toggle them during the frame.
- Style, ImDrawList: Renamed `style.AntiAliasedShapes` to `style.AntiAliasedFill` for consistency and as a way to explicitly break code that manipulate those flag at runtime. You can now manipulate ImDrawList::Flags.
- Style, Begin: Removed `ImGuiWindowFlags_ShowBorders` window flag. Borders are now fully set up in the ImGuiStyle structure (see e.g. `style.FrameBorderSize`, `style.WindowBorderSize`, `style.PopupBorderSize`).
  Use `ImGui::ShowStyleEditor()` to look them up.
  Please note that the style system will keep evolving (hopefully stabilizing in Q1 2018), and so custom styles will probably subtly break over time.
  It is recommended that you use the `StyleColorsClassic()`, `StyleColorsDark()`, `StyleColorsLight()` functions. Also see `ShowStyleSelector()`.
- Style: Removed `ImGuiCol_ComboBg` in favor of combo boxes using `ImGuiCol_PopupBg` for consistency. Combo are normal pop-ups.
- Style: Renamed `ImGuiCol_ChildWindowBg` to `ImGuiCol_ChildBg`.
- Style: Renamed `style.ChildWindowRounding` to `style.ChildRounding`, `ImGuiStyleVar_ChildWindowRounding` to `ImGuiStyleVar_ChildRounding`.
- Removed obsolete redirection functions: SetScrollPosHere() - marked obsolete in v1.42, July 2015.
- Removed obsolete redirection functions: GetWindowFont(), GetWindowFontSize() - marked obsolete in v1.48, March 2016.

Other Changes:

- Added `io.OptCursorBlink` option to allow disabling cursor blinking. (#1427) [renamed to io.ConfigCursorBlink in 1.63]
- Added `GetOverlayDrawList()` helper to quickly get access to a ImDrawList that will be rendered in front of every windows.
- Added `GetFrameHeight()` helper which returns `(FontSize + style.FramePadding.y * 2)`.
- Drag and Drop: Added Beta API to easily use drag and drop patterns between imgui widgets.
  - Setup a source on a widget with `BeginDragDropSource()`, `SetDragDropPayload()`, `EndDragDropSource()` functions.
  - Receive data with `BeginDragDropTarget()`, `AcceptDragDropPayload()`, `EndDragDropTarget()`.
  - See ImGuiDragDropFlags for various options.
  - The ColorEdit4() and ColorButton() widgets now support Drag and Drop.
  - The API is tagged as Beta as it still may be subject to small changes.
- Drag and Drop: When drag and drop is active, tree nodes and collapsing header can be opened by hovering on them for 0.7 seconds.
- Renamed io.OSXBehaviors to io.OptMacOSXBehaviors. Should not affect users as the compile-time default is usually enough. (#473, #650)
- Style: Added StyleColorsDark() style. (#707) [@dougbinks]
- Style: Added StyleColorsLight() style. Best used with frame borders + thicker font than the default font. (#707)
- Style: Added style.PopupRounding setting. (#1112)
- Style: Added style.FrameBorderSize, style.WindowBorderSize, style.PopupBorderSize. Removed ImGuiWindowFlags_ShowBorders window flag!
  Borders are now fully set up in the ImGuiStyle structure. Use ImGui::ShowStyleEditor() to look them up. (#707, fix #819, #1031)
- Style: Various small changes to the classic style (most noticeably, buttons are now using blue shades). (#707)
- Style: Renamed ImGuiCol_ChildWindowBg to ImGuiCol_ChildBg.
- Style: Renamed style.ChildWindowRounding to style.ChildRounding, ImGuiStyleVar_ChildWindowRounding to ImGuiStyleVar_ChildRounding.
- Style: Removed ImGuiCol_ComboBg in favor of combo boxes using ImGuiCol_PopupBg for consistency. (#707)
- Style: Made the ScaleAllSizes() helper rounds down every values so they are aligned on integers.
- Focus: Added SetItemDefaultFocus(), which in the current (master) branch behave the same as doing `if (IsWindowAppearing()) SetScrollHere()`.
  In the navigation branch this will also set the default focus. Prefer using this when creating combo boxes with `BeginCombo()` so your code will be forward-compatible with gamepad/keyboard navigation features. (#787)
- Combo: Pop-up grows horizontally to accommodate for contents that is larger then the parent combo button.
- Combo: Added BeginCombo()/EndCombo() API which allows use to submit content of any form and manage your selection state without relying on indices.
- Combo: Added ImGuiComboFlags_PopupAlignLeft flag to BeginCombo() to prioritize keeping the pop-up on the left side (for small-button-looking combos).
- Combo: Added ImGuiComboFlags_HeightSmall, ImGuiComboFlags_HeightLarge, ImGuiComboFlags_HeightLargest to easily provide desired pop-up height.
- Combo: You can use SetNextWindowSizeConstraints() before BeginCombo() to specify specific pop-up width/height constraints.
- Combo: Offset popup position by border size so that a double border isn't so visible. (#707)
- Combo: Recycling windows by using a stack number instead of a unique id, wasting less memory (like menus do).
- InputText: Added ImGuiInputTextFlags_NoUndoRedo flag. (#1506, #1508) [@ibachar]
- Window: Fixed auto-resize allocating too much space for scrollbar when SizeContents is bigger than maximum window size (fixes c0547d3). (#1417)
- Window: Child windows with MenuBar use regular WindowPadding.y so layout look consistent as child or as a regular window.
- Window: Begin(): Fixed appending into a child window with a second Begin() from a different window stack querying the wrong window for the window->Collapsed test.
- Window: Calling IsItemActive(), IsItemHovered() etc. after a call to Begin() provides item data for the title bar, so you can easily test if the title bar is being hovered, etc. (#823)
- Window: Made it possible to use SetNextWindowPos() on a child window.
- Window: Fixed a one frame glitch. When an appearing window claimed the focus themselves, the title bar wouldn't use the focused color for one frame.
- Window: Added ImGuiWindowFlags_ResizeFromAnySide flag to resize from any borders or from the lower-left corner of a window. This requires your backend to honor GetMouseCursor() requests for full usability. (#822)
- Window: Sizing fixes when using SetNextWindowSize() on individual axises.
- Window: Hide new window for one frame until they calculate their size. Also fixes SetNextWindowPos() given a non-zero pivot. (#1694)
- Window: Made mouse wheel scrolling accommodate better to windows that are smaller than the scroll step.
- Window: SetNextWindowContentSize() adjust for the size of decorations (title bar/menu bar), but _not_ for borders are we consistently make borders not affect layout.
  If you need a non-child window of an exact size with border enabled but zero window padding, you'll need to accommodate for the border size yourself.
- Window: Using the ImGuiWindowFlags_NoScrollWithMouse flag on a child window forwards the mouse wheel event to the parent window, unless either ImGuiWindowFlags_NoInputs or ImGuiWindowFlags_NoScrollbar are also set. (#1380, #1502)
- Window: Active Modal window always set the WantCaptureKeyboard flag. (#744)
- Window: Moving window doesn't use accumulating MouseDelta so straying out of imgui boundaries keeps moved imgui window at the same cursor-relative position.
- IsWindowFocused(): Added ImGuiFocusedFlags_ChildWindows flag to include child windows in the focused test. (#1382).
- IsWindowFocused(): Added ImGuiFocusedFlags_RootWindow flag to start focused test from the root (top-most) window. Obsolete IsRootWindowFocused(). (#1382)
- IsWindowHovered(): Added ImGuiHoveredFlags_ChildWindows flag to include child windows in the hovered test. (#1382).
- IsWindowHovered(): Added ImGuiHoveredFlags_RootWindow flag to start hovered test from the root (top-most) window. The combination of both flags obsoletes IsRootWindowOrAnyChildHovered(). (#1382)
- IsWindowHovered(): Fixed return value when an item is active to use the same logic as IsItemHovered(). (#1382, #1404)
- IsWindowHovered(): Always return true when current window is being moved. (#1382)
- Scrollbar: Fixed issues with vertical scrollbar flickering/appearing, typically when manually resizing and using a pattern of filling available height (e.g. full sized BeginChild).
- Scrollbar: Minor graphical fix for when scrollbar don't have enough visible space to display the full grab.
- Scrolling: Fixed padding and scrolling asymmetry where lower/right sides of a window wouldn't use WindowPadding properly + causing minor scrolling glitches.
- Tree: TreePush with zero arguments was ambiguous. Resolved by making it call TreePush(const void*). [@JasonWilkins]
- Tree: Renamed ImGuiTreeNodeFlags_AllowOverlapMode to ImGuiTreeNodeFlags_AllowItemOverlap. (#600, #1330)
- MenuBar: Fixed minor rendering issues on the right size when resizing a window very small and using rounded window corners.
- MenuBar: better software clipping to handle small windows, in particular child window don't have minimum constraints so we need to render clipped menus better.
- BeginMenu(): Tweaked the Arrow/Triangle displayed on child menu items.
- Columns: Clipping columns borders on Y axis on CPU because some Linux GPU drivers appears to be unhappy with triangle spanning large regions. (#125)
- Columns: Added ImGuiColumnsFlags_GrowParentContentsSize to internal API to restore old content sizes behavior (may be obsolete). (#1444, #125)
- Columns: Columns width is no longer lost when dragging a column to the right side of the window, until releasing the mouse button you have a chance to save them. (#1499, #125). [@ggtucker]
- Columns: Fixed dragging when using a same of columns multiple times in the frame. (#125)
- Indent(), Unindent(): Allow passing negative values.
- ColorEdit4(): Made IsItemActive() return true when picker pop-up is active. (#1489)
- ColorEdit4(): Tweaked tooltip so that the color button aligns more correctly with text.
- ColorEdit4(): Support drag and drop. Color buttons can be used as drag sources, and ColorEdit widgets as drag targets. (#143)
- ColorPicker4(): Fixed continuously returning true when holding mouse button on the sat/value/alpha locations. We only return true on value change. (#1489)
- NewFrame(): using literal strings in the most-frequently firing IM_ASSERT expressions to increase the odd of programmers seeing them (especially those who don't use a debugger).
- NewFrame() now asserts if neither Render or EndFrame have been called. Exposed EndFrame(). Made it legal to call EndFrame() more than one. (#1423)
- ImGuiStorage: Added BuildSortByKey() helper to rebuild storage from scratch.
- ImFont: Added GetDebugName() helper.
- ImFontAtlas: Added missing Thai punctuation in the GetGlyphRangesThai() ranges. (#1396) [@nProtect]
- ImDrawList: Removed 'bool anti_aliased = true' final parameter of ImDrawList::AddPolyline() and ImDrawList::AddConvexPolyFilled(). Anti-aliasing is controlled via the regular style.AntiAliased flags.
- ImDrawList: Added ImDrawList::AddImageRounded() helper. (#845) [@thedmd]
- ImDrawList: Refactored to make ImDrawList independent of ImGui. Removed static variable in PathArcToFast() which caused linking issues to some.
- ImDrawList: Exposed ImDrawCornerFlags, replaced occurrences of ~0 with an explicit ImDrawCornerFlags_All. NB: Inversed BotLeft (prev 1<<3, now 1<<2) and BotRight (prev 1<<2, now 1<<3).
- ImVector: Added ImVector::push_front() helper.
- ImVector: Added ImVector::contains() helper.
- ImVector: insert() uses grow_capacity() instead of using grow policy inconsistent with push_back().
- Internals: Remove requirement to define IMGUI_DEFINE_PLACEMENT_NEW to use the IM_PLACEMENT_NEW macro. (#1103)
- Internals: ButtonBehavior: Fixed ImGuiButtonFlags_NoHoldingActiveID flag from incorrectly setting the ActiveIdClickOffset field.
  This had no known effect within imgui code but could have affected custom drag and drop patterns. And it is more correct this way! (#1418)
- Internals: ButtonBehavior: Fixed ImGuiButtonFlags_AllowOverlapMode to avoid temporarily activating widgets on click before they have been correctly double-hovered. (#319, #600)
- Internals: Added SplitterBehavior() helper. (#319)
- Internals: Added IM_NEW(), IM_DELETE() helpers. (#484, #504, #1517)
- Internals: Basic refactor of the settings API which now allows external elements to be loaded/saved.
- Demo: Added ShowFontSelector() showing loaded fonts.
- Demo: Added ShowStyleSelector() to select among default styles. (#707)
- Demo: Renamed the emblematic ShowTestWindow() function to ShowDemoWindow().
- Demo: Style Editor: Added a "Simplified settings" sections with check-boxes for border size and frame rounding. (#707, #1019)
- Demo: Style Editor: Added combo box to select stock styles and select current font when multiple are loaded. (#707)
- Demo: Style Editor: Using local storage so Save/Revert button makes more sense without code passing its storage. Added horizontal scroll bar. Fixed Save/Revert button to be always accessible. (#1211)
- Demo: Console: Fixed context menu issue. (#1404)
- Demo: Console: Fixed incorrect positioning which was hidden by a minor scroll issue (this would affect people who copied the Console code as is).
- Demo: Constrained Resize: Added more test cases. (#1417)
- Demo: Custom Rendering: Fixed clipping rectangle extruding out of parent window.
- Demo: Layout: Removed unnecessary and misleading BeginChild/EndChild calls.
- Demo: The "Color Picker with Palette" demo supports drag and drop. (#143)
- Demo: Display better mouse cursor info for debugging backends.
- Demo: Stopped using rand() function in demo code.
- Examples: Added a handful of extra comments (about fonts, third-party libraries used in the examples, etc.).
- Examples: DirectX9: Handle loss of D3D9 device (D3DERR_DEVICELOST). (#1464)
- Examples: Added null_example/ which is helpful for quick testing on multiple compilers/settings without relying on graphics library.
- Fix for using alloca() in "Clang with Microsoft Codechain" mode.
- Various fixes, optimizations, comments.


-----------------------------------------------------------------------
 VERSION 1.52 (2017-10-27)
-----------------------------------------------------------------------

Decorated log: https://github.com/ocornut/imgui/releases/tag/v1.52

Breaking Changes:

- IO: `io.MousePos` needs to be set to ImVec2(-FLT_MAX,-FLT_MAX) when mouse is unavailable/missing, instead of ImVec2(-1,-1) as previously) This is needed so we can clear `io.MouseDelta` field when the mouse is made available again.
- Renamed `AlignFirstTextHeightToWidgets()` to `AlignTextToFramePadding()`. Kept inline redirection function (will obsolete).
- Obsoleted the legacy 5 parameters version of Begin(). Please avoid using it. If you need a transparent window background, uses `PushStyleColor()`. The old size parameter there was also misleading and equivalent to calling `SetNextWindowSize(size, ImGuiCond_FirstTimeEver)`. Kept inline redirection function (will obsolete).
- Obsoleted `IsItemHoveredRect()`, `IsMouseHoveringWindow()` in favor of using the newly introduced flags of `IsItemHovered()` and `IsWindowHovered()`. Kept inline redirection function (will obsolete). (#1382)
- Obsoleted 'SetNextWindowPosCenter()' in favor of using 1SetNextWindowPos()` with a pivot value which allows to do the same and more. Keep inline redirection function.
- Removed `IsItemRectHovered()`, `IsWindowRectHovered()` recently introduced in 1.51 which were merely the more consistent/correct names for the above functions which are now obsolete anyway. (#1382)
- Changed `IsWindowHovered()` default parameters behavior to return false if an item is active in another window (e.g. click-dragging item from another window to this window). You can use the newly introduced IsWindowHovered() flags to requests this specific behavior if you need it. (#1382)
- Renamed imconfig.h's `IMGUI_DISABLE_WIN32_DEFAULT_CLIPBOARD_FUNCS`/`IMGUI_DISABLE_WIN32_DEFAULT_IME_FUNCS` to `IMGUI_DISABLE_WIN32_DEFAULT_CLIPBOARD_FUNCTIONS`/`IMGUI_DISABLE_WIN32_DEFAULT_IME_FUNCTIONS` for consistency.
- Renamed ImFont::Glyph to ImFontGlyph. Kept redirection typedef (will obsolete).

Other Changes:

- ProgressBar: fixed rendering when straddling rounded area. (#1296)
- SliderFloat, DragFloat: Using scientific notation e.g. "%.1e" in the displayed format string doesn't mistakenly trigger rounding of the value. [@MomentsInGraphics]
- Combo, InputFloat, InputInt: Made the small button on the right side align properly with the equivalent colored button of ColorEdit4().
- IO: Tweaked logic for `io.WantCaptureMouse` so it now outputs false when e.g. hovering over void while an InputText() is active. (#621) [@pdoane]
- IO: Fixed `io.WantTextInput` from mistakenly outputting true when an activated Drag or Slider was previously turned into an InputText(). (#1317)
- Misc: Added flags to `IsItemHovered()`, `IsWindowHovered()` to access advanced hovering-test behavior. Generally useful for pop-ups and drag and drop behaviors: (relates to ~#439, #1013, #143, #925)
  - `ImGuiHoveredFlags_AllowWhenBlockedByPopup`
  - `ImGuiHoveredFlags_AllowWhenBlockedByActiveItem`
  - `ImGuiHoveredFlags_AllowWhenOverlapped`
  - `ImGuiHoveredFlags_RectOnly`
- Input: Added `IsMousePosValid()` helper.
- Input: Added `GetKeyPressedAmount()` to easily measure press count when the repeat rate is faster than the frame rate.
- Input/Focus: Disabled TAB and Shift+TAB when CTRL key is held.
- CheckBox: Now rendering a tick mark instead of a full square.
- ColorEdit4: Added "Copy as..." option in context menu. (#346)
- ColorPicker: Improved ColorPicker hue wheel color interpolation. (#1313) [@thevaber]
- ColorButton: Reduced bordering artifact that would be particularly visible with an opaque Col_FrameBg and FrameRounding enabled.
- ColorButton: Fixed rendering color button with a checkerboard if the transparency comes from the global style.Alpha and not from the actual source color.
- TreeNode: Added `ImGuiTreeNodeFlags_FramePadding` flag to conveniently create a tree node with full padding at the beginning of a line, without having to call `AlignTextToFramePadding()`.
- Trees: Fixed calling `SetNextTreeNodeOpen()` on a collapsed window leaking to the first tree node item of the next frame.
- Layout: Horizontal layout is automatically enforced in a menu bar, so you can use non-MenuItem elements without calling SameLine().
- Separator: Output a vertical separator when used inside a menu bar (or in general when horizontal layout is active, but that isn't exposed yet!).
- Window: Added `IsWindowAppearing()` helper (helpful e.g. as a condition before initializing some of your own things.).
- Window: Added pivot parameter to `SetNextWindowPos()`, making it possible to center or right align a window. Obsoleted `SetNextWindowPosCenter()`.
- Window: Fixed title bar color of top-most window under a modal window.
- Window: Fixed not being able to move a window by clicking on one of its child window. (#1337, #635)
- Window: Fixed `Begin()` auto-fit calculation code that predict the presence of a scrollbar so it works better when window size constraints are used.
- Window: Fixed calling `Begin()` more than once per frame setting `window_just_activated_by_user` which in turn would set enable the Appearing condition for that frame.
- Window: The implicit "Debug" window now uses a "Debug##Default" identifier instead of "Debug" to allow user creating a window called "Debug" without losing their custom flags.
- Window: Made the `ImGuiWindowFlags_NoMove` flag properly inherited from parent to child. In a setup with ParentWindow (no flag) -> Child (NoMove) -> SubChild (no flag), the user won't be able to move the parent window by clicking on SubChild. (#1381)
- Popups: Pop-ups can be closed with a right-click anywhere, without altering focus under the pop-up. (~#439)
- Popups: `BeginPopupContextItem()`, `BeginPopupContextWindow()` are now setup to allow reopening a context menu by right-clicking again. (~#439)
- Popups: `BeginPopupContextItem()` now supports a NULL string identifier and uses the last item ID if available.
- Popups: Added `OpenPopupOnItemClick()` helper which mimic `BeginPopupContextItem()` but doesn't do the BeginPopup().
- MenuItem: Only activating on mouse release. [@Urmeli0815] (was already fixed in nav branch).
- MenuItem: Made tick mark thicker (thick mark?).
- MenuItem: Tweaks to be usable inside a menu bar (nb: it looks like a regular menu and thus is misleading, prefer using Button() and regular widgets in menu bar if you need to). (#1387)
- ImDrawList: Fixed a rare draw call merging bug which could lead to undisplayed triangles. (#1172, #1368)
- ImDrawList: Fixed a rare bug in `ChannelsMerge()` when all contents has been clipped, leading to an extraneous draw call being created. (#1172, #1368)
- ImFont: Added `AddGlyph()` building helper for use by custom atlas builders.
- ImFontAtlas: Added support for CustomRect API to submit custom rectangles to be packed into the atlas. You can map them as font glyphs, or use them for custom purposes.
  After the atlas is built you can query the position of your rectangles in the texture and then copy your data there. You can use this features to create e.g. full color font-mapped icons.
- ImFontAtlas: Fixed fall-back handling when merging fonts, if a glyph was missing from the second font input it could have used a glyph from the first one. (#1349) [@inolen]
- ImFontAtlas: Fixed memory leak on build failure case when stbtt_InitFont failed (generally due to incorrect or supported font type). (#1391) (@Moka42)
- ImFontConfig: Added `RasterizerMultiply` option to alter the brightness of individual fonts at rasterization time, which may help increasing readability for some.
- ImFontConfig: Added `RasterizerFlags` to pass options to custom rasterizer (e.g. the [imgui_freetype](https://github.com/ocornut/imgui_club/tree/master/imgui_freetype) rasterizer in imgui_club has such options).
- ImVector: added resize() variant with initialization value.
- Misc: Changed the internal name formatting of child windows identifier to use slashes (instead of dots) as separator, more readable.
- Misc: Fixed compilation with `IMGUI_DISABLE_OBSOLETE_FUNCTIONS` defined.
- Misc: Marked all format+va_list functions with format attribute so GCC/Clang can warn about misuses.
- Misc: Fixed compilation on NetBSD due to missing alloca.h (#1319) [@RyuKojiro]
- Misc: Improved warnings compilation for newer versions of Clang. (#1324) (@waywardmonkeys)
- Misc: Added `io.WantMoveMouse flags` (from Nav branch) and honored in Examples applications. Currently unused but trying to spread Examples applications code that supports it.
- Misc: Added `IMGUI_DISABLE_FORMAT_STRING_FUNCTIONS` support in imconfig.h to allow user reimplementing the `ImFormatString()` functions e.g. to use stb_printf(). (#1038)
- Misc: [Windows] Fixed default Win32 `SetClipboardText()` handler leaving the Win32 clipboard handler unclosed on failure. [@pdoane]
- Style: Added `ImGuiStyle::ScaleAllSizes(float)` helper to make it easier to have application transition e.g. from low to high DPI with a matching style.
- Metrics: Draw window bounding boxes when hovering Pos/Size; List all draw layers; Trimming empty commands like Render() does.
- Examples: OpenGL3: Save and restore sampler state. (#1145) [@nlguillemot]
- Examples: OpenGL2, OpenGL3: Save and restore polygon mode. (#1307) [@JJscott]
- Examples: DirectX11: Allow creating device with feature level 10 since we don't really need much for that example. (#1333)
- Examples: DirectX9/10/12: Using the Win32 SetCapture/ReleaseCapture API to read mouse coordinates when they are out of bounds. (#1375) [@Gargaj, @ocornut]
- Tools: Fixed binary_to_compressed_c tool to return 0 when successful. (#1350) [@benvanik]
- Internals: Exposed more helpers and unfinished features in imgui_internal.h. (use at your own risk!).
- Internals: A bunch of internal refactoring, hopefully haven't broken anything! Merged a bunch of internal changes from the upcoming Navigation branch.
- Various tweaks, fixes and documentation changes.

Beta Navigation Branch:
(Lots of work has been done toward merging the Beta Gamepad/Keyboard Navigation branch (#787) in master.)
(Please note that this branch is always kept up to date with master. If you are using the navigation branch, some of the changes include:)
- Nav: Added `#define IMGUI_HAS_NAV` in imgui.h to ease sharing code between both branches. (#787)
- Nav: MainMenuBar now releases focus when user gets out of the menu layer. (#787)
- Nav: When applying focus to a window with only menus, the menu layer is automatically activated. (#787)
- Nav: Added `ImGuiNavInput_KeyMenu` (~Alt key) aside from ImGuiNavInput_PadMenu input as it is one differentiator of pad vs keyboard that was detrimental to the keyboard experience. Although isn't officially supported, it makes the current experience better. (#787)
- Nav: Move requests now wrap vertically inside Menus and Pop-ups. (#787)
- Nav: Allow to collapse tree nodes with NavLeft and open them with NavRight. (#787, #1079).
- Nav: It's now possible to navigate sibling of a menu-bar while navigating inside one of their child. If a Left<>Right navigation request fails to find a match we forward the request to the root menu. (#787, #126)
- Nav: Fixed `SetItemDefaultFocus` from stealing default focus when we are initializing default focus for a menu bar layer. (#787)
- Nav: Support for fall-back horizontal scrolling with PadLeft/PadRight (nb: fall-back scrolling is only used to navigate windows that have no interactive items). (#787)
- Nav: Fixed tool-tip from being selectable in the window selection list. (#787)
- Nav: `CollapsingHeader(bool*)` variant: fixed for `IsItemHovered()` not working properly in the nav branch. (#600, #787)
- Nav: InputText: Fixed using Up/Down history callback feature when Nav is enabled. (#787)
- Nav: InputTextMultiline: Fixed navigation/selection. Disabled selecting all when activating a multi-line text editor. (#787)
- Nav: More consistently drawing a (thin) navigation rectangle hover filled frames such as tree nodes, collapsing header, menus. (#787)
- Nav: Various internal refactoring.


-----------------------------------------------------------------------
 VERSION 1.51 (2017-08-24)
-----------------------------------------------------------------------

Decorated log: https://github.com/ocornut/imgui/releases/tag/v1.51

Breaking Changes:

Work on dear imgui has been gradually resuming. It means that fixes and new features should be tackled at a faster rate than last year. However, in order to move forward with the library and get rid of some cruft, I have taken the liberty to be a little bit more aggressive than usual with API breaking changes. Read the details below and search for those names in your code! In the grand scheme of things, those changes are small and should not affect everyone, but this is technically our most aggressive release so far in term of API breakage. If you want to be extra forward-facing, you can enable `#define IMGUI_DISABLE_OBSOLETE_FUNCTIONS` in your imconfig.h to disable the obsolete names/redirection.

- Renamed `IsItemHoveredRect()` to `IsItemRectHovered()`. Kept inline redirection function (will obsolete).
- Renamed `IsMouseHoveringWindow()` to `IsWindowRectHovered()` for consistency. Kept inline redirection function (will obsolete).
- Renamed `IsMouseHoveringAnyWindow()` to `IsAnyWindowHovered()` for consistency. Kept inline redirection function (will obsolete).
- Renamed `ImGuiCol_Columns***` enums to `ImGuiCol_Separator***`. Kept redirection enums (will obsolete).
- Renamed `ImGuiSetCond***` types and enums to `ImGuiCond***`. Kept redirection enums (will obsolete).
- Renamed `GetStyleColName()` to `GetStyleColorName()` for consistency. Unlikely to be used by end-user!
- Added `PushStyleColor(ImGuiCol idx, ImU32 col)` overload, which _might_ cause an "ambiguous call" compilation error if you are using ImColor() with implicit cast. Cast to ImU32 or ImVec4 explicitly to fix.
- Marked the weird `IMGUI_ONCE_UPON_A_FRAME` helper macro as obsolete. Prefer using the more explicit `ImGuiOnceUponAFrame`.
- Changed `ColorEdit4(const char* label, float col[4], bool show_alpha = true)` signature to `ColorEdit4(const char* label, float col[4], ImGuiColorEditFlags flags = 0)`, where flags 0x01 is a safe no-op (hello dodgy backward compatibility!). The new `ColorEdit4`/`ColorPicker4` functions have lots of available flags! Check and run the demo window, under "Color/Picker Widgets", to understand the various new options.
- Changed signature of `ColorButton(ImVec4 col, bool small_height = false, bool outline_border = true)` to `ColorButton(const char* desc_id, ImVec4 col, ImGuiColorEditFlags flags = 0, ImVec2 size = ImVec2(0,0))`. This function was rarely used and was very dodgy (no explicit ID!).
- Changed `BeginPopupContextWindow(bool also_over_items=true, const char* str_id=NULL, int mouse_button=1)` signature to `(const char* str_id=NULL, int mouse_button=1, bool also_over_items=true)`. This is perhaps the most aggressive change in this update, but note that the majority of users relied on default parameters completely, so this will affect only a fraction of users of this already rarely used function.
- Removed `IsPosHoveringAnyWindow()`, which was partly broken and misleading. In the vast majority of cases, people using that function wanted to use `io.WantCaptureMouse` flag. Replaced with IM_ASSERT + comment redirecting user to `io.WantCaptureMouse`. (#1237)
- Removed the old `ValueColor()` helpers, they are equivalent to calling `Text(label)` + `SameLine()` + `ColorButton()`.
- Removed `ColorEditMode()` and `ImGuiColorEditMode` type in favor of `ImGuiColorEditFlags` and parameters to the various Color*() functions. The `SetColorEditOptions()` function allows to initialize default but the user can still change them with right-click context menu. Commenting out your old call to `ColorEditMode()` may just be fine!

Other Changes:

- Added flags to `ColorEdit3()`, `ColorEdit4()`. The color edit widget now has a context-menu and access to the color picker. (#346)
- Added flags to `ColorButton()`. (#346)
- Added `ColorPicker3()`, `ColorPicker4()`. The API along with those of the updated `ColorEdit4()` was designed so you may use them in various situation and hopefully compose your own picker if required. There are a bunch of available flags, check the Demo window and comment for `ImGuiColorEditFlags_`. Some of the options it supports are: two color picker types (hue bar + sat/val rectangle, hue wheel + rotating sat/val triangle), display as u8 or float, lifting 0.0..1.0 constraints (currently rgba only), context menus, alpha bar, background checkerboard options, preview tooltip, basic revert. For simple use, calling the existing `ColorEdit4()` function as you did before will be enough, as you can now open the color picker from there. (#346) [@r-lyeh, @nem0, @thennequin, @dariomanesku and @ocornut]
- Added `SetColorEditOptions()` to set default color options (e.g. if you want HSV over RGBA, float over u8, select a default picker mode etc. at startup time without a user intervention. Note that the user can still change options with the context menu unless disabled with `ImGuiColorFlags_NoOptions` or explicitly enforcing a display type/picker mode etc.).
- Added user-facing `IsPopupOpen()` function. (#891) [@mkeeter]
- Added `GetColorU32(u32)` variant that perform the style alpha multiply without a floating-point round trip, and helps makes code more consistent when using ImDrawList APIs.
- Added `PushStyleColor(ImGuiCol idx, ImU32 col)` overload.
- Added `GetStyleColorVec4(ImGuiCol idx)` which is equivalent to accessing `ImGui::GetStyle().Colors[idx]` (aka return the raw style color without alpha alteration).
- ImFontAtlas: Added `GlyphRangesBuilder` helper class, which makes it easier to build custom glyph ranges from your app/game localization data, or add into existing glyph ranges.
- ImFontAtlas: Added `TexGlyphPadding` option. (#1282) [@jadwallis]
- ImFontAtlas: Made it possible to override size of AddFontDefault() (even if it isn't really recommended!).
- ImDrawList: Added `GetClipRectMin()`, `GetClipRectMax()` helpers.
- Fixed Ini saving crash if the ImGuiWindowFlags_NoSavedSettings gets removed from a window after its creation (unlikely!). (#1000)
- Fixed `PushID()`/`PopID()` from marking parent window as Accessed (which needlessly woke up the root "Debug" window when used outside of a regular window). (#747)
- Fixed an assert when calling `CloseCurrentPopup()` twice in a row. [@nem0]
- Window size can be loaded from .ini data even if ImGuiWindowFlags_NoResize flag is set. (#1048, #1056)
- Columns: Added `SetColumnWidth()`. (#913) [@ggtucker]
- Columns: Dragging a column preserve its width by default. (#913) [@ggtucker]
- Columns: Fixed first column appearing wider than others. (#1266)
- Columns: Fixed allocating space on the right-most side with the assumption of a vertical scrollbar. The space is only allocated when needed. (#125, #913, #893, #1138)
- Columns: Fixed the right-most column from registering its content width to the parent window, which led to various issues when using auto-resizing window or e.g. horizontal scrolling. (#519, #125, #913)
- Columns: Refactored some of the columns code internally toward a better API (not yet exposed) + minor optimizations. (#913) [@ggtucker, @ocornut]
- Popups: Most pop-ups windows can be moved by the user after appearing (if they don't have explicit positions provided by caller, or e.g. sub-menu pop-up). The previous restriction was totally arbitrary. (#1252)
- Tooltip: `SetTooltip()` is expanded immediately into a window, honoring current font / styling setting. Add internal mechanism to override tooltips. (#862)
- PlotHistogram: bars are drawn based on zero-line, so negative values are going under. (#828)
- Scrolling: Fixed return values of `GetScrollMaxX()`, `GetScrollMaxY()` when both scrollbars were enabled. Tweak demo to display more data. (#1271) [@degracode]
- Scrolling: Fixes for Vertical Scrollbar not automatically getting enabled if enabled Horizontal Scrollbar straddle the vertical limit. (#1271, #246)
- Scrolling: `SetScrollHere()`, `SetScrollFromPosY()`: Fixed Y scroll aiming when Horizontal Scrollbar is enabled. (#665).
- [Windows] Clipboard: Fixed not closing Win32 clipboard on early open failure path. (#1264)
- Removed an unnecessary dependency on int64_t which failed on some older compilers.
- Demo: Rearranged everything under Widgets in a more consistent way.
- Demo: Columns: Added Horizontal Scrolling demo. Tweaked another Columns demo. (#519, #125, #913)
- Examples: OpenGL: Various makefiles for MINGW, Linux. (#1209, #1229, #1209) [@fr500, @acda]
- Examples: Enabled vsync by default in example applications, so it doesn't confuse people that the sample run at 2000+ fps and waste an entire CPU. (#1213, #1151).
- Various other small fixes, tweaks, comments, optimizations.


-----------------------------------------------------------------------
 VERSION 1.50 (2017-06-02)
-----------------------------------------------------------------------

Decorated log: https://github.com/ocornut/imgui/releases/tag/v1.50

Breaking Changes:

- Added a void* user_data parameter to Clipboard function handlers. (#875)
- SameLine(x) with x>0.0f is now relative to left of column/group if any, and not always to left of window. This was sort of always the intent and hopefully breakage should be minimal.
- Renamed ImDrawList::PathFill() - rarely used directly - to ImDrawList::PathFillConvex() for clarity and consistency.
- Removed ImFontConfig::MergeGlyphCenterV in favor of a more multipurpose ImFontConfig::GlyphOffset.
- Style: style.WindowTitleAlign is now a ImVec2 (ImGuiAlign enum was removed). set to (0.5f,0.5f) for horizontal+vertical centering, (0.0f,0.0f) for upper-left, etc.
- BeginChild(const char*) now applies the stack id to the provided label, consistently with other functions as it should always have been. It shouldn't affect you unless (extremely unlikely) you were appending multiple times to a same child from different locations of the stack id. If that's the case, generate an id with GetId() and use it instead of passing string to BeginChild().

Other Changes:

- InputText(): Added support for CTRL+Backspace (delete word).
- InputText(): OSX uses Super+Arrows for home/end. Add Shortcut+Backspace support. (#650) [@michaelbartnett]
- InputText(): Got rid of individual OSX-specific options in ImGuiIO, added a single io.OSXBehaviors flag. (#473, #650)
- InputText(): Fixed pressing home key on last character when it isn't a trailing \n (#588, #815)
- InputText(): Fixed state corruption/crash bug in stb_textedit.h redo logic when exhausting undo/redo char buffer. (#715. #681)
- InputTextMultiline(): Fixed CTRL+DownArrow moving scrolling out of bounds.
- InputTextMultiline(): Scrollbar fix for when input and latched internal buffers differs in a way that affects vertical scrollbar existence. (#725)
- ImFormatString(): Fixed an overflow handling bug with implementation of vsnprintf() that do not return -1. (#793)
- BeginChild(const char*) now applies stack id to provided label, consistent with other widgets. (#894, #713)
- SameLine() with explicit X position is relative to left of group/columns. (ref #746, #125, #630)
- SliderInt(), SliderFloat() supports reverse direction (where v_min > v_max). (#854)
- SliderInt(), SliderFloat() better support for when v_min==v_max. (#919)
- SliderInt(), SliderFloat() enforces writing back value when interacting, to be consistent with other widgets. (#919)
- SliderInt, SliderFloat(): Fixed edge case where style.GrabMinSize being bigger than slider width can lead to a division by zero. (#919)
- Added IsRectVisible() variation with explicit start-end positions. (#768) [@thedmd]
- Fixed TextUnformatted() clipping bug in the large-text path when horizontal scroll has been applied. (#692, #246)
- Fixed minor text clipping issue in window title when using font straying above usual line. (#699)
- Fixed SetCursorScreenPos() fixed not adjusting CursorMaxPos as well.
- Fixed scrolling offset when using SetScrollY(), SetScrollFromPosY(), SetScrollHere() with menu bar.
- Fixed using IsItemActive() after EndGroup() or any widget using groups. (#840, #479)
- Fixed IsItemActive() lagging by one frame on initial widget activation. (#840)
- Fixed Separator() zero-height bounding box resulting in clipping when laying exactly on top line of clipping rectangle (#860)
- Fixed PlotLines() PlotHistogram() calling with values_count == 0.
- Fixed clicking on a window's void while staying still overzealously marking .ini settings as dirty. (#923)
- Fixed assert triggering when a window has zero rendering but has a callback. (#810)
- Scrollbar: Fixed rendering when sizes are negative to reduce glitches (which can happen with certain style settings and zero WindowMinSize).
- EndGroup(): Made IsItemHovered() work when an item was activated within the group. (#849)
- BulletText(): Fixed stopping to display formatted string after the '##' mark.
- Closing the focused window restore focus to the first active root window in descending z-order .(part of #727)
- Word-wrapping: Fixed a bug where we never wrapped after a 1 character word. [@sronsse]
- Word-wrapping: Fixed TextWrapped() overriding wrap position if one is already set. (#690)
- Word-wrapping: Fixed incorrect testing for negative wrap coordinates, they are perfectly legal. (#706)
- ImGuiListClipper: Fixed automatic-height calc path dumbly having user display element 0 twice. (#661, #716)
- ImGuiListClipper: Fix to behave within column. (#661, #662, #716)
- ImDrawList: Renamed ImDrawList::PathFill() to ImDrawList::PathFillConvex() for clarity. (BREAKING API)
- Columns: End() avoid calling Columns(1) if no columns set is open, not sure why it wasn't the case already (pros: faster, cons: exercise less code).
- ColorButton(): Fix ColorButton showing wrong hex value for alpha. (#1068) [@codecat]
- ColorEdit4(): better preserve inputting value out of 0..255 range, display then clamped in Hexadecimal form.
- Shutdown() clear out some remaining pointers for sanity. (#836)
- Added IMGUI_USE_BGRA_PACKED_COLOR option in imconfig.h (#767, #844) [@thedmd]
- Style: Removed the inconsistent shadow under RenderCollapseTriangle() (~#707)
- Style: Added ButtonTextAlign, ImGuiStyleVar_ButtonTextAlign. (#842)
- ImFont: Allowing to use up to 0xFFFE glyphs in same font (increased from previous 0x8000).
- ImFont: Added GetGlyphRangesThai() helper. [@nProtect]
- ImFont: CalcWordWrapPositionA() fixed font scaling with fallback character.
- ImFont: Calculate and store the approximate texture surface to get an idea of how costly each source font is.
- ImFontConfig: Added GlyphOffset to explicitly offset glyphs at font build time, useful for merged fonts. Removed MergeGlyphCenterV. (BREAKING API)
- Clarified asserts in CheckStacksSize() when there is a stack mismatch.
- Context: Support for #define-ing GImGui and IMGUI_SET_CURRENT_CONTEXT_FUNC to enable custom thread-based hackery (#586)
- Updated stb_truetype.h to 1.14 (added OTF support, removed warnings). (#883, #976)
- Updated stb_rect_pack.h to 0.10 (removed warnings). (#883)
- Added ImGuiMouseCursor_None enum value for convenient usage by app/backends.
- Clipboard: Added a void* user_data parameter to Clipboard function handlers. (#875) (BREAKING API)
- Internals: Refactor internal text alignment options to use ImVec2, removed ImGuiAlign. (#842, #222)
- Internals: Renamed ImLoadFileToMemory to ImFileLoadToMemory to be consistent with ImFileOpen + fix mismatching .h name. (#917)
- OS/Windows: Fixed Windows default clipboard handler leaving its buffer unfreed on application's exit. (#714)
- OS/Windows: No default IME handler when compiling for Windows using GCC. (#738)
- OS/Windows: Now using _wfopen() instead of fopen() to allow passing in paths/filenames with UTF-8 characters. (#917)
- Tools: binary_to_compressed_c: Avoid ?? trigraphs sequences in string outputs which break some older compilers. (#839)
- Demo: Added an extra 3-way columns demo.
- Demo: ShowStyleEditor: show font character map / grid in more details.
- Demo: Console: Fixed a completion bug when multiple candidates are equals and match until the end.
- Demo: Fixed 1-byte off overflow in the ShowStyleEditor() combo usage. (#783) [@bear24rw]
- Examples: Accessing ImVector fields directly, feel less stl-ey. (#810)
- Examples: OpenGL*: Saving/restoring existing scissor rectangle for completeness. (#807)
- Examples: OpenGL*: Saving/restoring active texture number (the value modified by glActiveTexture). (#1087, #1088, #1116)
- Examples: OpenGL*: Saving/restoring separate color/alpha blend functions correctly. (#1120) [@greggman]
- Examples: OpenGL2: Uploading font texture as RGBA32 to increase compatibility with users shaders for beginners. (#824)
- Examples: Vulkan: Countless fixes and improvements. (#785, #804, #910, #1017, #1039, #1041, #1042, #1043, #1080) [@martty, @Loftilus, @ParticlePeter, @SaschaWillems]
- Examples: DirectX9/10/10: Only call SetCursor(NULL) is io.MouseDrawCursor is set. (#585, #909)
- Examples: DirectX9: Explicitly setting viewport to match that other examples are doing. (#937)
- Examples: GLFW+OpenGL3: Fixed Shutdown() calling GL functions with NULL parameters if NewFrame was never called. (#800)
- Examples: GLFW+OpenGL2: Renaming opengl_example/ to opengl2_example/ for clarity.
- Examples: SDL+OpenGL: explicitly setting GL_UNPACK_ROW_LENGTH to reduce issues because SDL changes it. (#752)
- Examples: SDL2: Added build .bat files for Win32.
- Added various links to language/engine bindings.
- Various other minor fixes, tweaks, comments, optimizations.


-----------------------------------------------------------------------
 VERSION 1.49 (2016-05-09)
-----------------------------------------------------------------------

Decorated log: https://github.com/ocornut/imgui/releases/tag/v1.49

Breaking Changes:

- Renamed `SetNextTreeNodeOpened()` to `SetNextTreeNodeOpen()` for consistency, no redirection.
- Removed confusing set of `GetInternalState()`, `GetInternalStateSize()`, `SetInternalState()` functions. Now using `CreateContext()`, `DestroyContext()`, `GetCurrentContext()`, `SetCurrentContext()`. If you were using multiple contexts the change should be obvious and trivial.
- Obsoleted old signature of `CollapsingHeader(const char* label, const char* str_id = NULL, bool display_frame = true, bool default_open = false)`, as extra parameters were badly designed and rarely used. Most uses were using 1 parameter and shouldn't affect you. You can replace the "default_open = true" flag in new API with `CollapsingHeader(label, ImGuiTreeNodeFlags_DefaultOpen)`.
- Changed `ImDrawList::PushClipRect(ImVec4 rect)` to `ImDraw::PushClipRect(ImVec2 min,ImVec2 max,bool intersect_with_current_clip_rect=false)`. Note that higher-level `ImGui::PushClipRect()` is preferable because it will clip at logic/widget level, whereas `ImDrawList::PushClipRect()` only affect your renderer.
- Title bar (using ImGuiCol_TitleBg/ImGuiCol_TitleBgActive colors) isn't rendered over a window background (ImGuiCol_WindowBg color) anymore (see #655). If your TitleBg/TitleBgActive alpha was 1.0f or you are using the default theme it will not affect you. However if your TitleBg/TitleBgActive alpha was <1.0f you need to tweak your custom theme to readjust for the fact that we don't draw a WindowBg background behind the title bar.
  This helper function will convert an old TitleBg/TitleBgActive color into a new one with the same visual output, given the OLD color and the OLD WindowBg color. (Or If this is confusing, just pick the RGB value from title bar from an old screenshot and apply this as TitleBg/TitleBgActive. Or you may just create TitleBgActive from a tweaked TitleBg color.)

    ImVec4 ConvertTitleBgCol(const ImVec4& win_bg_col, const ImVec4& title_bg_col)
    {
       float new_a = 1.0f - ((1.0f - win_bg_col.w) * (1.0f - title_bg_col.w));
       float k = title_bg_col.w / new_a;
       return ImVec4((win_bg_col.x * win_bg_col.w + title_bg_col.x) * k, (win_bg_col.y * win_bg_col.w + title_bg_col.y) * k, (win_bg_col.z * win_bg_col.w + title_bg_col.z) * k, new_a);
    }

Other changes:

- New version of ImGuiListClipper helper calculates item height automatically. See comments and demo code. (#662, #661, #660)
- Added SetNextWindowSizeConstraints() to enable basic min/max and programmatic size constraints on window. Added demo. (#668)
- Added PushClipRect()/PopClipRect() (previously part of imgui_internal.h). Changed ImDrawList::PushClipRect() prototype. (#610)
- Added IsRootWindowOrAnyChildHovered() helper. (#615)
- Added TreeNodeEx() functions. (#581, #600, #190)
- Added ImGuiTreeNodeFlags_Selected flag to display TreeNode as "selected". (#581, #190)
- Added ImGuiTreeNodeFlags_AllowOverlapMode flag. (#600)
- Added ImGuiTreeNodeFlags_NoTreePushOnOpen flag (#590).
- Added ImGuiTreeNodeFlags_NoAutoOpenOnLog flag (previously private).
- Added ImGuiTreeNodeFlags_DefaultOpen flag (previously private).
- Added ImGuiTreeNodeFlags_OpenOnDoubleClick flag.
- Added ImGuiTreeNodeFlags_OpenOnArrow flag.
- Added ImGuiTreeNodeFlags_Leaf flag, always opened, no arrow, for convenience. For simple use case prefer using TreeAdvanceToLabelPos()+Text().
- Added ImGuiTreeNodeFlags_Bullet flag, to add a bullet to Leaf node or replace Arrow with a bullet.
- Added TreeAdvanceToLabelPos(), GetTreeNodeToLabelSpacing() helpers. (#581, #324)
- Added CreateContext()/DestroyContext()/GetCurrentContext()/SetCurrentContext(). Obsoleted nearly identical GetInternalState()/SetInternalState() functions. (#586, #269)
- Added NewLine() to undo a SameLine() and as a shy reminder that horizontal layout support hasn't been implemented yet.
- Added IsItemClicked() helper. (#581)
- Added CollapsingHeader() variant with close button. (#600)
- Fixed MenuBar missing lower border when borders are enabled.
- InputText(): Fixed clipping of cursor rendering in case it gets out of the box (which can be forced w/ ImGuiInputTextFlags_NoHorizontalScroll. (#601)
- Style: Changed default IndentSpacing from 22 to 21. (#581, #324)
- Style: Fixed TitleBg/TitleBgActive color being rendered above WindowBg color, which was inconsistent and causing visual artifact. (#655)
  This broke the meaning of TitleBg and TitleBgActive. Only affect values where Alpha<1.0f. Fixed default theme. Read comments in "API BREAKING CHANGES" section to convert.
- Relative rendering of order of Child windows creation is preserved, to allow more control with overlapping children. (#595)
- Fixed GetWindowContentRegionMax() being off by ScrollbarSize amount when explicit SizeContents is set.
- Indent(), Unindent(): optional non-default indenting width. (#324, #581)
- Bullet(), BulletText(): Slightly bigger. Less polygons.
- ButtonBehavior(): fixed subtle old bug when a repeating button would also return true on mouse release (barely noticeable unless RepeatRate is set to be very slow). (#656)
- BeginMenu(): a menu that becomes disabled while open gets closed down, facilitate user's code. (#126)
- BeginGroup(): fixed using within Columns set. (#630)
- Fixed a lag in reading the currently hovered window when dragging a window. (#635)
- Obsoleted 4 parameters version of CollapsingHeader(). Refactored code into TreeNodeBehavior. (#600, #579)
- Scrollbar: minor fix for top-right rounding of scrollbar background when window has menu bar but no title bar.
- MenuItem(): the check mark renders in disabled color when menu item is disabled.
- Fixed clipping rectangle floating point representation to ensure renderer-side float point operations yield correct results in typical DirectX/GL settings. (#582, 597)
- Fixed GetFrontMostModalRootWindow(), fixing missing fade-out when a combo pop was used stacked over a modal window. (#604)
- ImDrawList: Added AddQuad(), AddQuadFilled() helpers.
- ImDrawList: AddText() refactor, moving some code to ImFont, reserving less unused vertices when large vertical clipping occurs.
- ImFont: Added RenderChar() helper.
- ImFont: Added AddRemapChar() helper. (#609)
- ImFontConfig: Clarified persistence requirement of GlyphRanges array. (#651)
- ImGuiStorage: Added bool helper functions for completeness.
- AddFontFromMemoryCompressedTTF(): Fix ImFontConfig propagation. (#587)
- Renamed majority of use of the word "opened" to "open" for clarity. Renamed SetNextTreeNodeOpened() to SetNextTreeNodeOpen(). (#625, #579)
- Examples: OpenGL3: Saving/restoring glActiveTexture() state. (#602)
- Examples: DirectX9: save/restore all device state.
- Examples: DirectX9: Removed dependency on d3dx9.h, d3dx9.lib, dxguid.lib so it can be used in a DirectXMath.h only environment. (#611)
- Examples: DirectX10/X11: Apply depth-stencil state (no use of depth buffer). (#640, #636)
- Examples: DirectX11/X11: Added comments on removing dependency on D3DCompiler. (#638)
- Examples: SDL: Initialize video+timer subsystem only.
- Examples: Apple/iOS: lowered XCode project deployment target from 10.7 to 10.11. (#598, #575)


-----------------------------------------------------------------------
 VERSION 1.48 (2016-04-09)
-----------------------------------------------------------------------

Decorated log: https://github.com/ocornut/imgui/releases/tag/v1.48

Breaking Changes:

- Consistently honoring exact width passed to PushItemWidth() (when positive), previously it would add extra FramePadding.x*2 over that width. Some hand-tuned layout may be affected slightly. (#346)
- Style: removed `style.WindowFillAlphaDefault` which was confusing and redundant, baked alpha into `ImGuiCol_WindowBg` color. If you had a custom WindowBg color but didn't change WindowFillAlphaDefault, multiply WindowBg alpha component by 0.7. Renamed `ImGuiCol_TooltipBg` to `ImGuiCol_PopupBG`, applies to other types of pop-ups. `bg_alpha` parameter of 5-parameters version of Begin() is an override. (#337)
- InputText(): Added BufTextLen field in ImGuiTextEditCallbackData. Requesting user to update it if the buffer is modified in the callback. Added a temporary length-check assert to minimize panic for the 3 people using the callback. (#541)
- Renamed GetWindowFont() to GetFont(), GetWindowFontSize() to GetFontSize(). Kept inline redirection function (will obsolete). (#340)

Other Changes:

- Consistently honoring exact width passed to PushItemWidth(), previously it would add extra FramePadding.x*2 over that width. Some hand-tuned layout may be affected slightly. (#346)
- Fixed clipping of child windows within parent not taking account of child outer clipping boundaries (including scrollbar, etc.). (#506)
- TextUnformatted(): Fixed rare crash bug with large blurb of text (2k+) not finished with a '\n' and fully above the clipping Y line. (#535)
- IO: Added 'KeySuper' field to hold CMD keyboard modifiers for OS X. Updated all examples accordingly. (#473)
- Added ImGuiWindowFlags_ForceVerticalScrollbar, ImGuiWindowFlags_ForceHorizontalScrollbar flags. (#476)
- Added IM_COL32 macros to generate a U32 packed color, convenient for direct use of ImDrawList api. (#346)
- Added GetFontTexUvWhitePixel() helper, convenient for direct use of ImDrawList api.
- Selectable(): Added ImGuiSelectableFlags_AllowDoubleClick flag to allow user reacting on double-click. (@zapolnov) (#516)
- Begin(): made the close button explicitly set the boolean to false instead of toggling it. (#499)
- BeginChild()/EndChild(): fixed incorrect layout to allow widgets submitted after an auto-fitted child window. (#540)
- BeginChild(): Added ImGuiWindowFlags_AlwaysUseWindowPadding flag to ensure non-bordered child window uses window padding. (#462)
- Fixed InputTextMultiLine(), ListBox(), BeginChildFrame(), ProgressBar(): outer frame not honoring bordering. (#462, #503)
- Fixed Image(), ImageButtion() rendering a rectangle 1 px too large on each axis. (#457)
- SetItemAllowOverlap(): Promoted from imgui_internal.h to public imgui.h api. (#517)
- Combo(): Right-most button stays highlighted when pop-up is open.
- Combo(): Display pop-up above if there's isn't enough space below / or select largest side. (#505)
- DragFloat(), SliderFloat(), InputFloat(): fixed cases of erroneously returning true repeatedly after a text input modification (e.g. "0.0" --> "0.000" would keep returning true). (#564)
- DragFloat(): Always apply value when mouse is held/widget active, so that an always-resetting variable (e.g. non saved local) can be passed.
- InputText(): OS X friendly behaviors: Word movement uses ALT key; Shortcuts uses CMD key; Double-clicking text select a single word; Jumping to next word sets cursor to end of current word instead of beginning of current word. (@zhiayang), (#473)
- InputText(): Added BufTextLen in ImGuiTextEditCallbackData. Requesting user to maintain it if buffer is modified. Zero-ing structure properly before use. (#541)
- CheckboxFlags(): Added support for testing/setting multiple flags at the same time. (@DMartinek) (#555)
- TreeNode(), CollapsingHeader() fixed not being able to use "##" sequence in a formatted label.
- ColorEdit4(): Empty label doesn't add InnerSpacing.x, matching behavior of other widgets. (#346)
- ColorEdit4(): Removed unnecessary calls to scanf() when idle in hexadecimal edit mode.
- BeginPopupContextItem(), BeginPopupContextWindow(): added early out optimization.
- CaptureKeyboardFromApp() / CaptureMouseFromApp(): added argument to allow clearing the capture flag. (#533)
- ImDrawList: Fixed index-overflow check broken by AddText() casting current index back to ImDrawIdx. (#514)
- ImDrawList: Fixed incorrect removal of trailing draw command if it is a callback command.
- ImDrawList: Allow windows with only a callback only to be functional. (#524)
- ImDrawList: Fixed ImDrawList::AddRect() which used to render a rectangle 1 px too large on each axis. (#457)
- ImDrawList: Fixed ImDrawList::AddCircle() to fit precisely within bounding box like AddCircleFilled() and AddRectFilled(). (#457)
- ImDrawList: AddCircle(), AddRect() takes optional thickness parameter.
- ImDrawList: Added AddTriangle().
- ImDrawList: Added PrimQuadUV() helper to ease custom rendering of textured quads (require primitive reserve).
- ImDrawList: Allow AddText(ImFont\* font, float font_size, ...) variant to take NULL/0.0f as default.
- ImFontAtlas: heuristic increase default texture width up for large number of glyphs. (#491)
- ImTextBuffer: Fixed empty() helper which was utterly broken.
- Metrics: allow to inspect individual triangles in draw calls.
- Demo: added more draw primitives in the Custom Rendering example. (#457)
- Demo: extra comments and example for PushItemWidth(-1) patterns.
- Demo: InputText password demo filters out blanks. (#515)
- Demo: Fixed malloc/free mismatch and leak when destructing demo console, if it has been used. (@fungos) (#536)
- Demo: plot code doesn't use ImVector to avoid heap allocation and be more friendly to custom allocator users. (#538)
- Fixed compilation on DragonFly BSD (@mneumann) (#563)
- Examples: Vulkan: Added a Vulkan example (@Loftilus) (#549)
- Examples: DX10, DX11: Saving/restoring most device state so dropping render function in your codebase shouldn't have DX device side-effects. (#570)
- Examples: DX10, DX11: Fixed ImGui_ImplDX??_NewFrame() from recreating device objects if render isn't called (g_pVB not set).
- Examples: OpenGL3: Fix BindVertexArray/BindBuffer order. (@nlguillemot) (#527)
- Examples: OpenGL: skip rendering and calling glViewport() if we have zero-fixed buffer. (#486)
- Examples: SDL2+OpenGL3: Fix context creation options. Made ImGui_ImplSdlGL3_NewFrame() signature match GL2 one. (#468, #463)
- Examples: SDL2+OpenGL2/3: Fix for high-dpi displays. (@nickgravelyn)
- Various extra comments and clarification in the code.
- Various other fixes and optimizations.


-----------------------------------------------------------------------
 VERSION 1.47 (2015-12-25)
-----------------------------------------------------------------------

Decorated log: https://github.com/ocornut/imgui/releases/tag/v1.47

Changes:

- Rebranding "ImGui" -> "dear imgui" as an optional first name to reduce ambiguity with IMGUI term. (#21)
- Added ProgressBar(). (#333)
- InputText(): Added ImGuiInputTextFlags_Password mode: hide display, disable logging/copying to clipboard. (#237, #363, #374)
- Added GetColorU32() helper to retrieve color given enum with global alpha and extra applied.
- Added ImGuiIO::ClearInputCharacters() superfluous helper.
- Fixed ImDrawList draw command merging bug where using PopClipRect() along with PushTextureID()/PopTextureID() functions
  would occasionally restore an incorrect clipping rectangle.
- Fixed ImDrawList draw command merging so PushTextureID(XXX)/PopTextureID()/PushTextureID(XXX) sequence are now properly merged.
- Fixed large popups positioning issues when their contents on either axis is larger than DisplaySize,
  and WindowPadding < DisplaySafeAreaPadding.
- Fixed border rendering in various situations when using non-pixel aligned glyphs.
- Fixed border rendering of windows to always contain the border within the window.
- Fixed Shutdown() leaking font atlas data if NewFrame() was never called. (#396, #303)
- Fixed int>void\* warnings for 64-bit architectures with fancy warnings enabled.
- Renamed the dubious Color() helpers to ValueColor() - dangerously named, rarely used and probably to be made obsolete.
- InputText(): Fixed and better handling of using keyboard while mouse button if being held and dragging. (#429)
- InputText(): Replace OS IME (Input Method Editor) cursor on top-left when we are not text editing.
- TreeNode(), CollapsingHeader(), Bullet(), BulletText(): various sizing and layout fixes to better support laying out
  multiple item with different height on same line. (#414, #282)
- Begin(): Initial window creation with ImGuiWindowFlags_NoBringToFrontOnFocus flag pushes it at the front of global window list.
- BeginPopupContextWindow() and BeginPopupContextVoid() reopen window on subsequent click. (#439)
- ColorEdit4(): Fixed broken tooltip on hovering the color button. (actually fixes #373, #380)
- ImageButton(): uses FrameRounding up to a maximum of available framing size. (#394)
- Columns: Fixed bug with indentation within columns, also making code a bit shorter/faster. (#414, #125)
- Columns: Columns set with no implicit id include the columns count within the id to reduce collisions. (#125)
- Columns: Removed one unnecessary allocation when columns are not used by a window. (#125)
- ImFontAtlas: Tweaked GetGlyphRangesJapanese() so it is easier to modify.
- ImFontAtlas: Updated stb_rect_pack.h to 0.08.
- Metrics: Fixed computing ImDrawCmd bounding box when the draw buffer have been unindexed.
- Demo: Added a simple "Property Editor" demo applet. (#125, #414)
- Demo: Fixed assertion in "Custom Rendering" demo when holding both mouse buttons. (#393)
- Demo: Lots of extra comments, fixes.
- Demo: Tweaks to Style Editor.
- Examples: Not clearing input data/tex data in atlas (will be required for dynamic atlas anyway).
- Examples: Added /Zi (output debug information) to Win32 batch files.
- Examples: Various fixes for resizing window and recreating graphic context.
- Examples: OpenGL2/3: Save/restore viewport as part of default render function. (#392, #441).
- Examples; OpenGL3: Fixed gl3w.c for Linux when compiled with a C++ compiler. (#411)
- Examples: DirectX: Removed assumption about Unicode build in example main.cpp. (#399)
- Examples: DirectX10: Added DirectX10 example. (#424)
- Examples: DirectX11: Downgraded requirement from shader model 5.0 to 4.0. (#420)
- Examples: DirectX11: Removed Debug flag from graphics context. (#415)
- Examples: Added SDL+OpenGL3 example. (#356)


-----------------------------------------------------------------------
 VERSION 1.46 (2015-10-18)
-----------------------------------------------------------------------

Decorated log: https://github.com/ocornut/imgui/releases/tag/v1.46

Changes:

- Begin*(): added ImGuiWindowFlags_NoFocusOnAppearing flag. (#314)
- Begin*(): added ImGuiWindowFlags_NoBringToFrontOnFocus flag.
- Added GetDrawData() alternative to setting a Render function pointer in ImGuiIO structure.
- Added SetClipboardText(), GetClipboardText() helper shortcuts that user code can call directly without reading
  from the ImGuiIO structure (to match MemAlloc/MemFree)
- Fixed handling of malformed UTF-8 at the end of a non-zero terminated string range.
- Fixed mouse click detection when passing DeltaTime 0.0. (#338)
- Fixed IsKeyReleased() and IsMouseReleased() returning true on the first frame.
- Fixed using SetNextWindow\* functions on Modal windows with a ImGuiSetCond_Appearing condition. (#377)
- IsMouseHoveringRect(): Added 'bool clip' parameter to disable clipping provided rectangle. (#316)
- InputText(): added ImGuiInputTextFlags_ReadOnly flag. (#211)
- InputText(): lose cursor/undo-stack when reactivating focus is buffer has changed size.
- InputText(): fixed ignoring text inputs when ALT or ALTGR are pressed. (#334)
- InputText(): fixed mouse-dragging not tracking the cursor when text doesn't fit. (#339)
- InputText(): fixed cursor pixel-perfect alignment when horizontally scrolling.
- InputText(): fixed crash when passing a buf_size==0 (which can be of use for read-only selectable text boxes). (#360)
- InputFloat() fixed explicit precision modifier, both display and input were broken.
- PlotHistogram(): improved rendering of histogram with a lot of values.
- Dummy(): creates an item so functions such as IsItemHovered() can be used.
- BeginChildFrame() helper: added the extra_flags parameter.
- Scrollbar: fixed rounding of background + child window consistenly have ChildWindowBg color under ScrollbarBg fill. (#355).
- Scrollbar: background color less translucent in default style so it works better when changing background color.
- Scrollbar: fixed minor rendering offset when borders are enabled. (#365)
- ImDrawList: fixed 1 leak per ImDrawList using the ChannelsSplit() API (via Columns). (#318)
- ImDrawList: fixed rectangle rendering glitches with width/height <= 1/2 and rounding enabled.
- ImDrawList: AddImage() uv parameters default to (0,0) and (1,1).
- ImFontAtlas: Added TexDesiredWidth and tweaked default cheapo best-width choice. (#327)
- ImFontAtlas: Added GetGlyphRangesKorean() helper to retrieve unicode ranges for Korean. (#348)
- ImGuiTextFilter::Draw() helper return bool and build when filter is modified.
- ImGuiTextBuffer: added c_str() helper.
- ColorEdit4(): fixed hovering the color button always showing 1.0 alpha. (#373)
- ColorConvertFloat4ToU32() round the floats instead of truncating them.
- Window: Fixed window lower-right clipping limit so it plays more friendly with both OpenGL and DirectX coordinates.
- Internal: Extracted a EndFrame() function out of Render() but kept it internal/private + clarified some asserts. (#335)
- Internal: Added missing IMGUI_API definitions in imgui_internal.h (#326)
- Internal: ImLoadFileToMemory() return void\* instead of taking void*\* + allow optional int\* file_size.
- Demo: Horizontal scrollbar demo allows to enable simultanaeous scrollbars on both axises.
- Tools: binary_to_compressed_c.cpp: added -nocompress option.
- Examples: Added example for the Marmalade platform.
- Examples: Added batch files to build Windows examples with VS.
- Examples: OpenGL3: Saving/restoring more GL state correctly. (#347)
- Examples: OpenGL2/3: Added msys2/mingw64 target to Makefiles.


-----------------------------------------------------------------------
 VERSION 1.45 (2015-09-01)
-----------------------------------------------------------------------

Decorated log: https://github.com/ocornut/imgui/releases/tag/v1.45

Breaking Changes:

- With the addition of better horizontal scrolling primitives I had to make some consistency fixes.
  `GetCursorPos()` `SetCursorPos()` `GetContentRegionMax()` `GetWindowContentRegionMin()` `GetWindowContentRegionMax()`
  are now incorporating the scrolling amount. They were incorrectly not incorporating this amount previously.
  It PROBABLY shouldn't break anything, but that depends on how you used them. Namely:
  - If you always used SetCursorPos() with values relative to GetCursorPos() there shouldn't be a problem.
    However if you used absolute coordinates, note that SetCursorPosY(100.0f) will put you at +100 from the initial Y position (which may be scrolled out of the view), NOT at +100 from the window top border. Since there wasn't any official scrolling value on X axis (past just manually moving the cursor) this can only affect you if you used to set absolute coordinates on the Y axis which is hopefully rare/unlikely, and trivial to fix.
  - The value of GetWindowContentRegionMax() isn't necessarily close to GetWindowWidth() if horizontally scrolling.
    Previously they were roughly interchangeable (roughly because the content region exclude window padding).

Other Changes:

- Added Horizontal Scrollbar via ImGuiWindowFlags_HorizontalScroll (#246).
- Added GetScrollX(), GetScrollX(), GetScrollMaxX() apis (#246).
- Added SetNextWindowContentSize(), SetNextWindowContentWidth() to explicitly set the content size of a window, which
  define the range of scrollbar. When set explicitly it also define the base value from which widget width are derived.
- Added IO.WantTextInput telling when ImGui is expecting text input, so that e.g. OS on-screen keyboard can be enabled.
- Added printf attribute to printf-like text formatting functions (Clang/GCC).
- Added GetMousePosOnOpeningCurrentPopup() helper.
- Added GetContentRegionAvailWidth() helper.
- Malformed UTF-8 data don't terminate string, output 0xFFFD instead (#307).
- ImDrawList: Added AddBezierCurve(), PathBezierCurveTo() API for cubic bezier curves (#311).
- ImDrawList: Allow to override ImDrawIdx type (#292).
- ImDrawList: Added an assert on overflowing index value (#292).
- ImDrawList: Fixed issues with channels split/merge. Now functional without manually adding a draw cmd. Added comments.
- ImDrawData: Added ScaleClipRects() helper useful when rendering scaled. (#287).
- Fixed Bullet() inconsistent layout behaviour when clipped.
- Fixed IsWindowHovered() not taking account of window hoverability (may be disabled because of a popup).
- Fixed InvisibleButton() not honoring negative size consistently with other widgets that do so.
- Fixed OpenPopup() accessing current window, effectively opening "Debug" when called from an empty window stack.
- TreeNode(): Fixed IsItemHovered() result being inconsistent with interaction visuals (#282).
- TreeNode(): Fixed mouse interaction padding past the node label being accounted for in layout (#282).
- BeginChild(): Passing a ImGuiWindowFlags_NoMove inhibits moving parent window from this child.
- BeginChild() fixed missing rounding for child sizes which leaked into layout and have items misaligned.
- Begin(): Removed default name = "Debug" parameter. We already have a "Debug" window pushed to the stack in the first place so it's not really a useful default.
- Begin(): Minor fixes with windows main clipping rectangle (e.g. child window with border).
- Begin(): Window flags are only read on the first call of the frame. Subsequent calls ignore flags, which allows appending to a window without worryin about flags.
- InputText(): ignore character input when ctrl/alt are held. (Normally those text input are ignored by most wrappers.) (#279).
- Demo: Fixed incorrectly formed string passed to Combo (#298).
- Demo: Added simple Log demo.
- Demo: Added horizontal scrolling example + enabled in console, log and child examples (#246).
- Style: made scrollbars rounded by default. Because nice. Minor menu bar background alpha tweak. (#246)
- Metrics: display indices along with triangles count (#299) and some internal state.
- ImGuiTextFilter::PassFilter() supports string range. Added [] helper to ImGuiTextBuffer.
- ImGuiTextFilter::Draw() default parameter width=0.0f for no override, allow override with negative values.
- Examples: OpenGL2/OpenGL3: fix for retina displays. Default font current lack crispness.
- Examples: OpenGL2/OpenGL3: save/restore more GL state correctly.
- Examples: DirectX9/DirectX11: resizing buffers dynamically (#299).
- Examples: DirectX9/DirectX11: added missing middle mouse button to Windows event handler.
- Examples: DirectX11: fix for Visual Studio 2015 presumably shipping with an updated version of DX11.
- Examples: iOS: fixed missing files in project.


-----------------------------------------------------------------------
 VERSION 1.44 (2015-08-08)
-----------------------------------------------------------------------

Decorated log: https://github.com/ocornut/imgui/releases/tag/v1.44

Breaking Changes:

- imgui.cpp has been split intro extra files: imgui_demo.cpp, imgui_draw.cpp, imgui_internal.h.
  Add the two extra .cpp to your project or #include them from another .cpp file. (#219)

Other Changes:

- Internal data structure and several useful functions are now exposed in imgui_internal.h. This should make it easier
  and more natural to extend ImGui. However please note that none of the content in imgui_internal.h is guaranteed
  for forward-compatibility and code using those types/functions may occasionally break. (#219)
- All sample code is in imgui_demo.cpp. Please keep this file in your project and consider allowing your code to call
  the ShowTestWindow() function as de-facto guide to ImGui features. It will be stripped out by the linker when unused.
- Added GetContentRegionAvail() helper (basically GetContentRegionMax() - GetCursorPos()).
- Added ImGuiWindowFlags_NoInputs for totally input-passthru window.
- Button(): honor negative size consistently with other widgets that do so (width -100 to align the button 100 pixels
  before the right-most position of the contents region).
- InputTextMultiline(): honor negative size consistently with other widgets that do so.
- Combo() clamp popup to lower edge of visible area.
- InputInt(): value doesn't pass through an int>float>int casting chain, fix handling lost of precision with "large" integer.
- InputInt() allow hexadecimal input (awkwardly via ImGuiInputTextFlags_CharsHexadecimal but we will allow format
  string in InputInt* later).
- Checkbox(), RadioButton(): fixed scaling of checkbox and radio button for the filling of "active" visual.
- Columns: never assume horizontal space for scrollbar if NoScrollbar flag is explicitly set.
- Slider: fixed using FramePadding between frame and grab visual. Scaling that spacing would look odd.
- Fixed lower-right resize grip hit box not scaling along with its rendered size (#287)
- ImDrawList: Fixed angles in ImDrawList::PathArcTo(), PathArcToFast() (v1.43) being off by an extra PI for no reason.
- ImDrawList: Added ImDrawList::AddText() shorthand helper.
- ImDrawList: Add missing support for anti-aliased thick-lines (#133, also ref #288)
- ImFontAtlas: Added AddFontFromMemoryCompressedBase85TTF() to load base85 encoded font string. Default font encoded
  as base85 saves ~100 lines / 26 KB of source code. Added base85 output to the binary_to_compressed_c tool.
- Build fix for MinGW (#276).
- Examples: OpenGL3: Fixed running on script core profiles for OSX (#277).
- Examples: OpenGL3: Simplified code using glBufferData for vertices as well (#277, #278)
- Examples: DirectX11: Clear font texture view to ensure Release() doesn't get called twice (#290).
- Updated to stb_truetype 1.07 (back to vanilla version as our minor changes are now in master & fix unlikely assert
  with odd fonts (#280)


-----------------------------------------------------------------------
 VERSION 1.43 (2015-07-17)
-----------------------------------------------------------------------

Decorated log: https://github.com/ocornut/imgui/releases/tag/v1.43

Breaking Changes:

- This is a rather important release and we unfortunately had to break the rendering API.
  ImGui now requires you to render indexed vertices instead of non-indexed ones. The fix should be very easy.
  Sorry for that! This change is saving a fair amount of CPU/GPU and enables us to get anti-aliasing for a marginal cost.
  Each ImDrawList now contains both a vertex buffer and an index buffer. For each command, render ElemCount/3 triangles
  using indices from the index buffer.
- If you are using a vanilla copy of one of the imgui_impl_XXXX.cpp provided in the example, you just need to update
  your copy and you can ignore the rest.
- The signature of the io.RenderDrawListsFn handler has changed
  From:  ImGui_XXXX_RenderDrawLists(ImDrawList** const cmd_lists, int cmd_lists_count)
  To:    ImGui_XXXX_RenderDrawLists(ImDrawData* draw_data)
  With:  argument   'cmd_lists'        -> 'draw_data->CmdLists'
         argument   'cmd_lists_count'  -> 'draw_data->CmdListsCount'
         ImDrawList 'commands'         -> 'CmdBuffer'
         ImDrawList 'vtx_buffer'       -> 'VtxBuffer'
         ImDrawList  n/a               -> 'IdxBuffer' (new)
         ImDrawCmd  'vtx_count'        -> 'ElemCount'
         ImDrawCmd  'clip_rect'        -> 'ClipRect'
         ImDrawCmd  'user_callback'    -> 'UserCallback'
         ImDrawCmd  'texture_id'       -> 'TextureId'
- If you REALLY cannot render indexed primitives, you can call the draw_data->DeIndexAllBuffers() method to de-index
  the buffers. This is slow and a waste of CPU/GPU. Prefer using indexed rendering!
  Refer to code in the examples/ folder or ask on the GitHub if you are unsure of how to upgrade. Please upgrade!

Other Changes:

- Added anti-aliasing on lines and shapes based on primitives by @MikkoMononen (#133).
  Between the use of indexed-rendering and the fact that the entire rendering codebase has been optimized and massaged
  enough, with anti-aliasing enabled ImGui 1.43 is now running FASTER than 1.41.
  Made some extra effort in making the code run faster in your typical Debug build.
- Anti-aliasing can be disabled in the ImGuiStyle structure via the AntiAliasedLines/AntiAliasedShapes fields for further gains.
- ImDrawList: Added AddPolyline(), AddConvexPolyFilled() with optional anti-aliasing.
- ImDrawList: Added stateful path building and stroking API. PathLineTo(), PathArcTo(), PathRect(), PathFill(), PathStroke()
  with optional anti-aliasing.
- ImDrawList: Added AddRectFilledMultiColor() helper.
- ImDrawList: Added multi-channel rendering so out of order elements can be rendered in separate channels and then merged
  back together (used by columns).
- ImDrawList: Fixed merging draw commands when equal clip rectangles are in the two first commands.
- ImDrawList: Fixed window draw lists not destructed properly on Shutdown().
- ImDrawData: Added DeIndexAllBuffers() helper.
- Added lots of new font options ImFontAtlas::AddFont() and the new ImFontConfig structure.
  - Added support for oversampling (ImFontConfig: OversampleH, OversampleV) and sub-pixel positioning (ImFontConfig: PixelSnapH).
    Oversampling allows sub-pixel positioning but can also be used as a way to get some leeway with scaling fonts without re-rasterizing.
  - Added GlyphExtraSpacing option to add extra horizontal spacing between characters (#242).
  - Added MergeMode option to merge glyphs from different font inputs into a same font (#182, #232).
  - Added FontDataOwnedByAtlas option to keep ownership from the TTF data buffer and request the atlas to make a copy (#220).
- Updated to stb_truetype 1.06 (+ minor mods) with better font rasterization.
- InputText: Added ImGuiInputTextFlags_NoHorizontalScroll flag.
- InputText: Added ImGuiInputTextFlags_AlwaysInsertMode flag.
- InputText: Added HasSelection() helper in ImGuiTextEditCallbackData as a clarification.
- InputText: Fix for using END key on a multi-line text editor (#275)
- Columns: Dispatch render of each column in a sub-draw list and merge on closure, saving a lot of draw calls! (#125)
- Popups: Fixed Combo boxes inside menus. (#272)
- Style: Added GrabRounding setting to make the sliders etc. grabs rounded.
- Changed SameLine() parameters from int to float.
- Fixed incorrect assert triggering when code stole ActiveID from user moving a window by calling e.g. SetKeyboardFocusHere().
- Fixed CollapsingHeader() label rendering outside its frame in columns context where ClipRect max isn't aligned with the
  right-side of the header.
- Metrics window: calculate bounding box of actual vertices when hovering a draw list.
- Examples: Showing more information in the Fonts section.
- Examples: Added a gratuitous About window.
- Examples: Updated all examples code (OpenGL/DX9/DX11/SDL/Allegro/iOS) to use indexed rendering.
- Examples: Fixed the SDL2 example to support Unicode text input (#274).


-----------------------------------------------------------------------
 VERSION 1.42 (2015-07-08)
-----------------------------------------------------------------------

Decorated log: https://github.com/ocornut/imgui/releases/tag/v1.42

Breaking Changes:

- Renamed SetScrollPosHere() to SetScrollHere(). Kept inline redirection function (will obsolete).
- Renamed GetScrollPosY() to GetScrollY(). Necessary to reduce confusion and make scrolling API consistent,
  because positions (e.g. cursor position) are not equivalent to scrolling amount.
- Removed obsolete GetDefaultFontData() function that would assert anyway.
  If you are updating from <1.30 you'll get a compile error instead of an assertion. (obsoleted 2015/01/11)

Other Changes:

- Added SDL2 example application (courtesy of @CedricGuillemet)
- Added iOS example application (courtesy of @joeld42)
- Added Allegro 5 example application (courtesy of @bggd)
- Added TitleBgActive color in style so focused window is made visible. (#253)
- Added CaptureKeyboardFromApp() / CaptureMouseFromApp() to manually enforce inputs capturing.
- Added DragFloatRange2() DragIntRange2() helpers. (#76)
- Added a Y centering ratio to SetScrollFromCursorPos() which can be used to aim the top or bottom of the window. (#150)
- Added SetScrollY(), SetScrollFromPos(), GetCursorStartPos() for manual scrolling manipulations. (#150).
- Added GetKeyIndex() helper for converting from ImGuiKey_\* enum to user's keycodes. Basically pulls from io.KeysMap[].
- Added missing ImGuiKey_PageUp, ImGuiKey_PageDown so more UI code can be written without referring to implementation-side keycodes.
- MenuItem() can be activated on release. (#245)
- Allowing NewFrame() with DeltaTime==0.0f to not assert.
- Fixed IsMouseDragging(). (#260)
- Fixed PlotLines(), PlotHistogram() using incorrect hovering test so they would show their tooltip even when there is
  a popup between mouse and the graph.
- Fixed window padding being reported incorrectly for child windows with borders when parent have no borders.
- Fixed a bug with TextUnformatted() clipping of long text blob when clipping y1 line sits on the first line of text. (#257)
- Fixed text baseline alignment of small button (no padding) after regular buttons.
- Fixed ListBoxHeader() not honoring negative sizes the same way as BeginChild() or BeginChildFrame(). (#263)
- Fixed warnings for more pedantic compiler settings (#258).
- ImVector<> cannot be re-defined anymore, cannot be replaced with std::vector<>. Allowed us to clean up and optimize
  lots of code. Yeah! (#262)
- ImDrawList: store pointer to their owner name for easier auditing/debugging.
- Examples: added scroll tracking example with SetScrollFromCursorPos().
- Examples: metrics windows render clip rectangle when hovering over a draw call.
- Lots of small optimization (particularly to run faster on unoptimized builds) and tidying up.
- Added font links in extra_fonts/ + instructions for using compressed fonts in C array.


-----------------------------------------------------------------------
 VERSION 1.41 (2015-06-26)
-----------------------------------------------------------------------

Decorated log: https://github.com/ocornut/imgui/releases/tag/v1.41

Breaking Changes:

- Changed ImageButton() default bg_col parameter from (0,0,0,1) (black) to (0,0,0,0) (transparent).
  Only makes a difference when texture have transparency.
- Changed Selectable() API from (label, selected, size) to (label, selected, flags, size).
  Size override should be used very rarely so hopefully it doesn't affect many people. Sorry!

Other Changes:

- Added InputTextMultiline() multi-line text editor, vertical scrolling, selection, optimized enough to handle rather
  big chunks of text in stateless context (thousands of lines are ok), option for allowing Tab to be input, option
  for validating with Return or Ctrl+Return (#200).
- Added modal window API, BeginPopupModal(), follows the popup api scheme. Modal windows can be closed by clicking
  outside. By default the rest of the screen is dimmed (using ImGuiCol_ModalWindowDarkening). Modal windows can be stacked.
- Added GetGlyphRangesCyrillic() helper (#237).
- Added SetNextWindowPosCenter() to center a window prior to knowing its size. (#249)
- Added IsWindowHovered() helper.
- Added IsMouseReleased(), IsKeyReleased() helpers to allow to user to avoid tracking them. (#248)
- Allow Set*WindowSize() calls to be used with popups.
- Window: AutoFit can be triggered on each axis separately via SetNextWindowSize(), etc.
- Window: fixed scrolling with mouse wheel while window was collapsed.
- Window: fixed mouse wheel scroll issues.
- DragFloat(), SliderFloat(): Fixed rounding of negative numbers which sometime made the negative lower bound unreachable.
- InputText(): lifted character count limit.
- InputText(): fixes in case of using per-window font scaling.
- Selectable(), MenuItem(): do not use frame rounding for hovering/selection.
- Selectable(): Added flag ImGuiSelectableFlags_DontClosePopups.
- Selectable(): Added flag ImGuiSelectableFlags_SpanAllColumns (#125).
- Combo(): Fixed issue with activating a Combo() not taking active id (#241).
- ColorButton(), ColorEdit4(): fix to ensure that the colored square stays square when non-default padding settings are used.
- BeginChildFrame(): returns bool like BeginChild() for clipping.
- SetScrollPosHere(): takes account of item height + more accurate centering + fixed precision issue.
- ImFont: ignoring '\r'.
- ImFont: added GetCharAdvance() helper. Exposed font Ascent and font Descent.
- ImFont: additional rendering optimizations.
- Metrics windows display storage size.


-----------------------------------------------------------------------
 VERSION 1.40 (2015-05-31)
-----------------------------------------------------------------------

Decorated log: https://github.com/ocornut/imgui/releases/tag/v1.40

Breaking Changes:

- The BeginPopup() API (introduced in 1.37) had to be changed to allow for stacked popups and menus.
  Use OpenPopup() to toggle the opened state and BeginPopup() to append.**
- The third parameter of Button(), 'repeat_if_held' has been removed. While it's been very rarely used,
  some code will possibly break if you didn't rely on the default parameter.
  Use PushButtonRepeat()/PopButtonRepeat() to configure repeat.
- Renamed IsRectClipped() to !IsRectVisible() for consistency (opposite return value!). Kept inline redirection function (will obsolete)
- Renamed GetWindowCollapsed() to IsWindowCollapsed() for consistency. Kept inline indirection function (will obsolete).

Other Changes:

- Menus: Added a menu system! Menus are typically populated with menu items and sub-menus, but you can add any sort of
  widgets in them (buttons, text inputs, sliders, etc.). (#126)
- Menus: Added MenuItem() to append a menu item. Optional shortcut display, acts a button & toggle with checked/unchecked state,
  disabled mode. Menu items can be used in any window.
- Menus: Added BeginMenu() to append a sub-menu. Note that you generally want to add sub-menu inside a popup or a menu-bar.
  They will work inside a normal window but it will be a bit unusual.
- Menus: Added BeginMenuBar() to append to window menu-bar (set ImGuiWindowFlags_MenuBar to enable).
- Menus: Added BeginMainMenuBar() helper to append to a fullscreen main menu-bar.
- Popups: Support for stacked popups. Each popup level inhibit inputs to lower levels. The menus system is based on this. (#126).
- Popups: Added BeginPopupContextItem(), BeginPopupContextWindow(), BeginPopupContextVoid() to create a popup window on mouse-click.
- Popups: Popups have borders by default (#197), attenuated border alpha in default theme.
- Popups & Tooltip: Fit within display. Handling various positioning/sizing/scrolling edge cases. Better hysteresis when moving
  in corners. Tooltip always tries to stay away from mouse-cursor.
- Added ImGuiStorage::GetVoidPtrRef() for manipulating stored void*.
- Added IsKeyDown() IsMouseDown() as convenience and for consistency with existing functions (instead of reading them from IO structures).
- Added Dummy() helper to advance layout by a given size. Unlike InvisibleButton() this doesn't catch any click.
- Added configurable io.KeyRepeatDelay, io.KeyRepeatRate keyboard and mouse repeat rate.
- Added PushButtonRepeat() / PopButtonRepeat() to enable hold-button-to-repeat press on any button.
- Removed the third 'repeat' parameter of Button().
- Added IsAnyItemHovered() helper.
- Added GetItemsLineHeightWithSpacing() helper.
- Added ImGuiListClipper helper for clipping large list of evenly sized items, to avoid using CalcListClipping() directly.
- Separator: within group start on group horizontal offset. (#205)
- InputText: Fixed incorrect edit state after text buffer is appended to by user via the callback. (#206)
- InputText: CTRL+letter-key shortcuts (e.g. CTRL+C/V/X) makes sure only CTRL is pressed. (#214)
- InputText: Fixed cursor generating a zero-width wire-frame rectangle turning into a division by zero (would go unnoticed
  unless you trapped exceptions).
- InputFloatN/InputIntN: Flags parameter added to match scalar versions. (#218)
- Selectable: Horizontal filling not declared to ItemSize() so Selectable(),SameLine() works and we can better auto-fit the window.
- Selectable: Handling text baseline alignment for line that aren't of text height.
- Combo: Empty label doesn't add ItemInnerSpacing alignment, matching other widgets.
- EndGroup: Carries the text base offset from the last line of the group (sort of incorrect but better than nothing,
  should use the first line of the group, will implement in the future).
- Columns: distinguish columns-set ID from other widgets as a convenience, added asserts and sailors.
- ListBox: ListBox() function only use public API to encourage creating custom versions. ListBoxHeader() can return false.
- ListBox: Uses ImGuiListClipper and assume items of matching height, so large lists can be handled.
- Plot: overlay label clipped within frame when not fitting.
- Window: Added ImGuiSetCond_Appearing to test the hidden->visible transition in SetWindow***/SetNextWindow*** functions.
- Window: Auto-fitting cancel out one worth of vertical spacing for vertical symmetry (like what group and tooltip do).
- Window: Default item width for auto-resizing windows expressed as a factor of font height, scales better with different font.
- Window: Fixed auto-fit calculation mismatch of whether a scrollbar will be added by maximum height clamping. Also honor NoScrollBar in the case of height clamping, not adding extra horizontal space.
- Window: Hovering require to hover same child window. Reverted 860cf57 (December 3). Might break something if you have
  child overlapping items in parent window.
- Window: Fixed appending multiple times to an existing child via multiple BeginChild/EndChild calls to same child name.
  Allows a simple form of out-of-order appending.
- Window: Fixed auto-filling child window using WindowMinSize at their minimum size, irrelevant.
- Metrics: Added io.MetricsActiveWindows counter. (#213.
- Metrics: Added io.MetricsAllocs counter (number of active memory allocations).
- Metrics: ShowMetricsWindow() shows popups stack, allocations.
- Style: Added style.DisplayWindowPadding to prevent windows from reaching edges of display (similar to style.DisplaySafeAreaPadding which is still in effect and also affect popups/tooltips).
- Style: Removed style.AutoFitPadding, using style.WindowPadding makes more sense (the default values were already the same).
- Style: Added style.ScrollbarRounding. (#212)
- Style: Added ImGuiCol_TextDisabled for disabled text. Added TextDisabled() helper.
- Style: Added style.WindowTitleAlign alignment options, to e.g. center title on windows. (#222)
- ImVector: tweak growth strategy, matches vector from VS2010.
- ImFontAtlas: Added ClearFonts(), making the different clear funcs more explicit. (#224)
- ImFontAtlas: Fixed appending new fonts without clearing existing fonts. Clearing input data left to application. (#224)
- ImDrawList: Merge draw command better, cases of multiple Begin/End gets merged properly.
- Store common stacked settings contiguously in memory to avoid heap allocation for unused features, and reduce cache misses.
- Shutdown() tests for g.IO.Fonts not being NULL to ease use of multiple ImGui contexts. (#207)
- Added IMGUI_DISABLE_OBSOLETE_FUNCTIONS define to disable the functions that are meant to be removed.
- Examples: Added ? marks with tooltips next to various widgets. Added more comments in the demo window.
- Examples: Added Menu-bar example.
- Examples: Added Simple Layout example.
- Examples: AutoResize demo doesn't use TextWrapped().
- Examples: Console example uses standard malloc/free, makes more sense as a copy & pastable example.
- Examples: DirectX9/11: Fixed key mapping for down arrow.
- Examples: DirectX9/11: hide OS cursor if ImGui is drawing it. (#155)
- Examples: DirectX11: explicitly set rasterizer state.
- Examples: OpenGL3: Add conditional compilation of forward compat as required by glfw on OSX. (#229)
- Fixed build with Visual Studio 2008 (possibly earlier versions as well).
- Other fixes, comments, tweaks.


-----------------------------------------------------------------------

For older version, see https://github.com/ocornut/imgui/releases