Drag and Drop: can use BeginDragDropSource() for other than the left mouse button (#1637, #3885)
As long as the item has an ID (for ID-less items will add new functionalities later.
Amend 2c3c5125
diff --git a/docs/CHANGELOG.txt b/docs/CHANGELOG.txt
index 2b29ab8..5a8dbfb 100644
--- a/docs/CHANGELOG.txt
+++ b/docs/CHANGELOG.txt
@@ -49,7 +49,7 @@
- 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)
- Window, Nav: Fixed crash when calling SetWindowFocus(NULL) as the time a new window appears. (#3865) [@nem0]
-- DragScalar: Fixed crash when using DragScalar() directly (not via common wrapper like DragFloat() etc.)
+- 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]
@@ -59,6 +59,8 @@
- 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)
- Added GetAllocatorFunctions() to facilitate sharing allocators accross DLL boundaries. (#3836)
- 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.
diff --git a/imgui.cpp b/imgui.cpp
index 67a82b9..3080a27 100644
--- a/imgui.cpp
+++ b/imgui.cpp
@@ -3024,6 +3024,7 @@
g.ActiveIdTimer = 0.0f;
g.ActiveIdHasBeenPressedBefore = false;
g.ActiveIdHasBeenEditedBefore = false;
+ g.ActiveIdMouseButton = -1;
if (id != 0)
{
g.LastActiveId = id;
@@ -9643,27 +9644,45 @@
memset(&g.DragDropPayloadBufLocal, 0, sizeof(g.DragDropPayloadBufLocal));
}
-// Call when current ID is active.
// When this returns true you need to: a) call SetDragDropPayload() exactly once, b) you may render the payload visual/description, c) call EndDragDropSource()
+// If the item has an identifier:
+// - This assume/require the item to be activated (typically via ButtonBehavior).
+// - Therefore if you want to use this with a mouse button other than left mouse button, it is up to the item itself to activate with another button.
+// - We then pull and use the mouse button that was used to activate the item and use it to carry on the drag.
+// If the item has no identifier:
+// - Currently always assume left mouse button.
bool ImGui::BeginDragDropSource(ImGuiDragDropFlags flags)
{
ImGuiContext& g = *GImGui;
ImGuiWindow* window = g.CurrentWindow;
+ // FIXME-DRAGDROP: While in the common-most "drag from non-zero active id" case we can tell the mouse button,
+ // in both SourceExtern and id==0 cases we may requires something else (explicit flags or some heuristic).
+ ImGuiMouseButton mouse_button = ImGuiMouseButton_Left;
+
bool source_drag_active = false;
ImGuiID source_id = 0;
ImGuiID source_parent_id = 0;
- ImGuiMouseButton mouse_button = ImGuiMouseButton_Left;
if (!(flags & ImGuiDragDropFlags_SourceExtern))
{
source_id = window->DC.LastItemId;
- if (source_id != 0 && g.ActiveId != source_id) // Early out for most common case
- return false;
- if (g.IO.MouseDown[mouse_button] == false)
- return false;
-
- if (source_id == 0)
+ if (source_id != 0)
{
+ // Common path: items with ID
+ if (g.ActiveId != source_id)
+ return false;
+ if (g.ActiveIdMouseButton != -1)
+ mouse_button = g.ActiveIdMouseButton;
+ if (g.IO.MouseDown[mouse_button] == false)
+ return false;
+ g.ActiveIdAllowOverlap = false;
+ }
+ else
+ {
+ // Uncommon path: items without ID
+ if (g.IO.MouseDown[mouse_button] == false)
+ return false;
+
// If you want to use BeginDragDropSource() on an item with no unique identifier for interaction, such as Text() or Image(), you need to:
// A) Read the explanation below, B) Use the ImGuiDragDropFlags_SourceAllowNullID flag, C) Swallow your programmer pride.
if (!(flags & ImGuiDragDropFlags_SourceAllowNullID))
@@ -9690,10 +9709,6 @@
if (g.ActiveId == source_id) // Allow the underlying widget to display/return hovered during the mouse release frame, else we would get a flicker.
g.ActiveIdAllowOverlap = is_hovered;
}
- else
- {
- g.ActiveIdAllowOverlap = false;
- }
if (g.ActiveId != source_id)
return false;
source_parent_id = window->IDStack.back();
@@ -9896,7 +9911,7 @@
flags |= (g.DragDropSourceFlags & ImGuiDragDropFlags_AcceptNoDrawDefaultRect); // Source can also inhibit the preview (useful for external sources that lives for 1 frame)
if (!(flags & ImGuiDragDropFlags_AcceptNoDrawDefaultRect) && payload.Preview)
{
- // FIXME-DRAG: Settle on a proper default visuals for drop target.
+ // FIXME-DRAGDROP: Settle on a proper default visuals for drop target.
r.Expand(3.5f);
bool push_clip_rect = !window->ClipRect.Contains(r);
if (push_clip_rect) window->DrawList->PushClipRect(r.Min - ImVec2(1, 1), r.Max + ImVec2(1, 1));
diff --git a/imgui.h b/imgui.h
index 7e6489e..c47d47b 100644
--- a/imgui.h
+++ b/imgui.h
@@ -755,8 +755,11 @@
IMGUI_API void LogTextV(const char* fmt, va_list args) IM_FMTLIST(1);
// Drag and Drop
- // - If you stop calling BeginDragDropSource() the payload is preserved however it won't have a preview tooltip (we currently display a fallback "..." tooltip as replacement)
- IMGUI_API bool BeginDragDropSource(ImGuiDragDropFlags flags = 0); // call when the current item is active. If this return true, you can call SetDragDropPayload() + EndDragDropSource()
+ // - On source items, call BeginDragDropSource(), if it returns true also call SetDragDropPayload() + EndDragDropSource().
+ // - On target candidates, call BeginDragDropTarget(), if it returns true also call AcceptDragDropPayload() + EndDragDropTarget().
+ // - If you stop calling BeginDragDropSource() the payload is preserved however it won't have a preview tooltip (we currently display a fallback "..." tooltip, see #1725)
+ // - An item can be both drag source and drop target.
+ IMGUI_API bool BeginDragDropSource(ImGuiDragDropFlags flags = 0); // call after submitting an item which may be dragged. when this return true, you can call SetDragDropPayload() + EndDragDropSource()
IMGUI_API bool SetDragDropPayload(const char* type, const void* data, size_t sz, ImGuiCond cond = 0); // type is a user defined string of maximum 32 characters. Strings starting with '_' are reserved for dear imgui internal types. Data is copied and held by imgui.
IMGUI_API void EndDragDropSource(); // only call EndDragDropSource() if BeginDragDropSource() returns true!
IMGUI_API bool BeginDragDropTarget(); // call after submitting an item that may receive a payload. If this returns true, you can call AcceptDragDropPayload() + EndDragDropTarget()
diff --git a/imgui_internal.h b/imgui_internal.h
index f17229a..46df05c 100644
--- a/imgui_internal.h
+++ b/imgui_internal.h
@@ -1568,7 +1568,7 @@
ActiveIdClickOffset = ImVec2(-1, -1);
ActiveIdWindow = NULL;
ActiveIdSource = ImGuiInputSource_None;
- ActiveIdMouseButton = 0;
+ ActiveIdMouseButton = -1;
ActiveIdPreviousFrame = 0;
ActiveIdPreviousFrameIsAlive = false;
ActiveIdPreviousFrameHasBeenEditedBefore = false;
