Drag and drop API experiment
diff --git a/imgui.cpp b/imgui.cpp
index 0c2e72a..ad4a189 100644
--- a/imgui.cpp
+++ b/imgui.cpp
@@ -2231,6 +2231,15 @@
if (g.ScalarAsInputTextId && g.ActiveId != g.ScalarAsInputTextId)
g.ScalarAsInputTextId = 0;
+ // Elapse drag & drop payload
+ if (g.DragDropActive && g.DragDropPayload.DataFrameCount + 1 < g.FrameCount)
+ {
+ g.DragDropActive = false;
+ g.DragDropPayload.Clear();
+ g.DragDropPayloadBufHeap.clear();
+ memset(&g.DragDropPayloadBufLocal, 0, sizeof(g.DragDropPayloadBufLocal));
+ }
+
// Update keyboard input state
memcpy(g.IO.KeysDownDurationPrev, g.IO.KeysDownDuration, sizeof(g.IO.KeysDownDuration));
for (int i = 0; i < IM_ARRAYSIZE(g.IO.KeysDown); i++)
@@ -5868,7 +5877,8 @@
{
if (hovered && (flags & ImGuiButtonFlags_PressedOnClickRelease))
if (!((flags & ImGuiButtonFlags_Repeat) && g.IO.MouseDownDurationPrev[0] >= g.IO.KeyRepeatDelay)) // Repeat mode trumps <on release>
- pressed = true;
+ if (!g.DragDropActive)
+ pressed = true;
ClearActiveID();
}
}
@@ -9426,7 +9436,7 @@
else
window->DrawList->AddRect(bb.Min, bb.Max, GetColorU32(ImGuiCol_FrameBg), rounding); // Color button are often in need of some sort of border
- if (hovered && !(flags & ImGuiColorEditFlags_NoTooltip))
+ if (!(flags & ImGuiColorEditFlags_NoTooltip) && hovered)
ColorTooltip(desc_id, &col.x, flags & (ImGuiColorEditFlags_NoAlpha | ImGuiColorEditFlags_AlphaPreview | ImGuiColorEditFlags_AlphaPreviewHalf));
return pressed;
@@ -10585,6 +10595,164 @@
}
//-----------------------------------------------------------------------------
+// DRAG AND DROP
+//-----------------------------------------------------------------------------
+
+// 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()
+bool ImGui::BeginDragDropSource(ImGuiDragDropFlags flags, int mouse_button)
+{
+ ImGuiContext& g = *GImGui;
+ ImGuiWindow* window = g.CurrentWindow;
+ if (g.IO.MouseDown[mouse_button] == false)
+ return false;
+ if (g.ActiveId != window->DC.LastItemId)
+ return false;
+
+ if (IsMouseDragging(mouse_button))
+ {
+ if (!g.DragDropActive)
+ {
+ ImGuiPayload& payload = g.DragDropPayload;
+ payload.Clear();
+ payload.SourceId = g.ActiveId;
+ payload.SourceParentId = window->IDStack.back();
+ g.DragDropActive = true;
+ g.DragDropSourceFlags = flags;
+ g.DragDropMouseButton = mouse_button;
+ }
+
+ if (!(flags & ImGuiDragDropFlags_SourceNoAutoTooltip))
+ {
+ // FIXME-DRAG
+ //SetNextWindowPos(g.IO.MousePos - g.ActiveIdClickOffset - g.Style.WindowPadding);
+ //PushStyleVar(ImGuiStyleVar_Alpha, g.Style.Alpha * 0.60f); // This is better but e.g ColorButton with checkboard has issue with transparent colors :(
+ SetNextWindowPos(g.IO.MousePos);
+ PushStyleColor(ImGuiCol_PopupBg, GetStyleColorVec4(ImGuiCol_PopupBg) * ImVec4(1.0f, 1.0f, 1.0f, 0.6f));
+ BeginTooltipEx(ImGuiWindowFlags_NoInputs | ImGuiWindowFlags_ShowBorders);
+ }
+ return true;
+ }
+ return false;
+}
+
+void ImGui::EndDragDropSource()
+{
+ ImGuiContext& g = *GImGui;
+ IM_ASSERT(g.DragDropActive);
+ IM_ASSERT(g.DragDropPayload.DataFrameCount != -1); // Forgot to call SetDragDropSourcePayload(), at least once on the first frame of a successful BeginDragDropSource()
+
+ if (!(g.DragDropSourceFlags & ImGuiDragDropFlags_SourceNoAutoTooltip))
+ {
+ EndTooltip();
+ PopStyleColor();
+ //PopStyleVar();
+ }
+}
+
+// Use 'cond' to choose to submit paypload on drag start or every frame
+bool ImGui::SetDragDropPayload(const char* type, const void* data, size_t data_size, ImGuiCond cond)
+{
+ ImGuiContext& g = *GImGui;
+ ImGuiPayload& payload = g.DragDropPayload;
+ if (cond == 0)
+ cond = ImGuiCond_Always;
+
+ IM_ASSERT(type != NULL);
+ IM_ASSERT(strlen(type) < IM_ARRAYSIZE(payload.DataType)); // Payload type can be at most 8 characters longs
+ IM_ASSERT(data != NULL && data_size > 0);
+ IM_ASSERT(cond == ImGuiCond_Always || cond == ImGuiCond_Once);
+ IM_ASSERT(payload.SourceId != 0); // Not called between BeginDragDropSource() and EndDragDropSource()
+
+ if (cond == ImGuiCond_Always || payload.DataFrameCount == -1)
+ {
+ // Copy payload
+ ImStrncpy(payload.DataType, type, IM_ARRAYSIZE(payload.DataType));
+ g.DragDropPayloadBufHeap.resize(0);
+ if (data_size > sizeof(g.DragDropPayloadBufLocal))
+ {
+ // Store in heap
+ g.DragDropPayloadBufHeap.resize((int)data_size);
+ payload.Data = g.DragDropPayloadBufHeap.Data;
+ memcpy((void*)payload.Data, data, data_size);
+ }
+ else if (data_size > 0)
+ {
+ // Store locally
+ memset(&g.DragDropPayloadBufLocal, 0, sizeof(g.DragDropPayloadBufLocal));
+ payload.Data = g.DragDropPayloadBufLocal;
+ memcpy((void*)payload.Data, data, data_size);
+ }
+ else
+ {
+ payload.Data = NULL;
+ }
+ payload.DataSize = (int)data_size;
+ }
+ payload.DataFrameCount = g.FrameCount;
+
+ return (payload.AcceptFrameCount == g.FrameCount) || (payload.AcceptFrameCount == g.FrameCount - 1);
+}
+
+bool ImGui::BeginDragDropTarget()
+{
+ ImGuiContext& g = *GImGui;
+ if (!g.DragDropActive)
+ return false;
+
+ ImGuiWindow* window = g.CurrentWindow;
+ //if (!window->DC.LastItemRectHoveredRect || (g.ActiveId == g.DragDropPayload.SourceId || g.ActiveIdPreviousFrame == g.DragDropPayload.SourceId))
+ if (!window->DC.LastItemRectHoveredRect || (window->DC.LastItemId && window->DC.LastItemId == g.DragDropPayload.SourceId))
+ return false;
+ if (window->RootWindow != g.HoveredWindow->RootWindow)
+ return false;
+
+ return true;
+}
+
+const ImGuiPayload* ImGui::AcceptDragDropPayload(const char* type, ImGuiDragDropFlags flags)
+{
+ ImGuiContext& g = *GImGui;
+ ImGuiWindow* window = g.CurrentWindow;
+ ImGuiPayload& payload = g.DragDropPayload;
+ IM_ASSERT(g.DragDropActive); // Not called between BeginDragDropTarget() and EndDragDropTarget() ?
+ IM_ASSERT(window->DC.LastItemRectHoveredRect); // Not called between BeginDragDropTarget() and EndDragDropTarget() ?
+ IM_ASSERT(payload.DataFrameCount != -1); // Internal/usage error, please report!
+ if (type != NULL && !payload.IsDataType(type))
+ return NULL;
+
+ if (payload.AcceptId == 0)
+ payload.AcceptId = window->DC.LastItemId;
+
+ bool was_accepted_previously = (payload.AcceptFrameCount == g.FrameCount - 1);
+ if (payload.AcceptFrameCount != g.FrameCount)
+ {
+ // Render drop visuals
+ if (!(flags & ImGuiDragDropFlags_AcceptNoDrawDefaultRect) && was_accepted_previously)
+ {
+ ImRect r = window->DC.LastItemRect;
+ r.Expand(4.0f);
+ window->DrawList->AddRectFilled(r.Min, r.Max, IM_COL32(255, 255, 0, 20), 0.0f); // FIXME-DRAG FIXME-STYLE
+ window->DrawList->AddRect(r.Min, r.Max, IM_COL32(255, 255, 0, 255), 0.0f, ~0, 2.0f); // FIXME-DRAG FIXME-STYLE
+ }
+ payload.AcceptFrameCount = g.FrameCount;
+ }
+
+ payload.Delivery = was_accepted_previously && IsMouseReleased(g.DragDropMouseButton);
+ if (!payload.Delivery && !(flags & ImGuiDragDropFlags_AcceptBeforeDelivery))
+ return NULL;
+
+ return &payload;
+}
+
+// We don't really use/need this now, but added it for the sake of consistency and because we might need it later.
+void ImGui::EndDragDropTarget()
+{
+ ImGuiContext& g = *GImGui;
+ IM_ASSERT(g.DragDropActive);
+}
+
+//-----------------------------------------------------------------------------
// PLATFORM DEPENDENT HELPERS
//-----------------------------------------------------------------------------
diff --git a/imgui_internal.h b/imgui_internal.h
index 1cb723c..5c82ea1 100644
--- a/imgui_internal.h
+++ b/imgui_internal.h
@@ -43,9 +43,11 @@
struct ImGuiMouseCursorData;
struct ImGuiPopupRef;
struct ImGuiWindow;
+struct ImGuiPayload; // User data payload for drag and drop operations
typedef int ImGuiLayoutType; // enum: horizontal or vertical // enum ImGuiLayoutType_
typedef int ImGuiButtonFlags; // flags: for ButtonEx(), ButtonBehavior() // enum ImGuiButtonFlags_
+typedef int ImGuiDragDropFlags; // flags: for *DragDrop*() // enum ImGuiDragDropFlags_
typedef int ImGuiItemFlags; // flags: for PushItemFlag() // enum ImGuiItemFlags_
typedef int ImGuiSeparatorFlags; // flags: for Separator() - internal // enum ImGuiSeparatorFlags_
typedef int ImGuiSliderFlags; // flags: for SliderBehavior() // enum ImGuiSliderFlags_
@@ -215,6 +217,15 @@
ImGuiSeparatorFlags_Vertical = 1 << 1
};
+// Flags for ImGui::BeginDragDropSource(), ImGui::AcceptDragDropPayload()
+enum ImGuiDragDropFlags_
+{
+ ImGuiDragDropFlags_SourceNoAutoTooltip = 1 << 0,
+ ImGuiDragDropFlags_AcceptBeforeDelivery = 1 << 1, // AcceptDragDropPayload() returns true even before the mouse button is released. You can then call IsDelivery() to test if the payload needs to be delivered.
+ ImGuiDragDropFlags_AcceptNoDrawDefaultRect = 1 << 2, // Do not draw the default highlight rectangle when hovering over target.
+ ImGuiDragDropFlags_AcceptPeekOnly = ImGuiDragDropFlags_AcceptBeforeDelivery | ImGuiDragDropFlags_AcceptNoDrawDefaultRect // For peeking ahead and inspecting the payload before delivery.
+};
+
// FIXME: this is in development, not exposed/functional as a generic feature yet.
enum ImGuiLayoutType_
{
@@ -404,6 +415,28 @@
ImGuiPopupRef(ImGuiID id, ImGuiWindow* parent_window, ImGuiID parent_menu_set, const ImVec2& mouse_pos) { PopupId = id; Window = NULL; ParentWindow = parent_window; ParentMenuSet = parent_menu_set; MousePosOnOpen = mouse_pos; }
};
+// Data payload for Drag and Drop operations
+struct ImGuiPayload
+{
+ // Members
+ const void* Data; // Data (copied and owned by dear imgui)
+ int DataSize; // Data size
+
+ // [Internal]
+ ImGuiID SourceId; // Source item id
+ ImGuiID SourceParentId; // Source parent id (if available)
+ ImGuiID AcceptId; // Target item id (set at the time of accepting the payload)
+ int AcceptFrameCount; // Last time a target expressed a desire to accept the source
+ int DataFrameCount; // Data timestamp
+ char DataType[8 + 1]; // Data type tag (short user-supplied string)
+ bool Delivery; // Set when AcceptDragDropPayload() was called and the mouse button is released over the target item
+
+ ImGuiPayload() { Clear(); }
+ void Clear() { SourceId = SourceParentId = AcceptId = 0; AcceptFrameCount = -1; Data = NULL; DataSize = 0; memset(DataType, 0, sizeof(DataType)); DataFrameCount = -1; Delivery = false; }
+ bool IsDataType(const char* type) const { return DataFrameCount != -1 && strcmp(type, DataType) == 0; }
+ bool IsDelivery() const { return Delivery; }
+};
+
// Main state for ImGui
struct ImGuiContext
{
@@ -472,6 +505,14 @@
ImGuiMouseCursor MouseCursor;
ImGuiMouseCursorData MouseCursorData[ImGuiMouseCursor_Count_];
+ // Drag and Drop
+ bool DragDropActive;
+ ImGuiDragDropFlags DragDropSourceFlags;
+ int DragDropMouseButton;
+ ImGuiPayload DragDropPayload;
+ ImVector<unsigned char> DragDropPayloadBufHeap; // We don't expose the ImVector<> directly
+ unsigned char DragDropPayloadBufLocal[8];
+
// Widget state
ImGuiTextEditState InputTextState;
ImFont InputTextPasswordFont;
@@ -547,6 +588,10 @@
SetNextTreeNodeOpenVal = false;
SetNextTreeNodeOpenCond = 0;
+ DragDropActive = false;
+ DragDropSourceFlags = 0;
+ DragDropMouseButton = -1;
+
ScalarAsInputTextId = 0;
ColorEditOptions = ImGuiColorEditFlags__OptionsDefault;
DragCurrentValue = 0.0f;
@@ -810,6 +855,14 @@
IMGUI_API void Scrollbar(ImGuiLayoutType direction);
IMGUI_API void VerticalSeparator(); // Vertical separator, for menu bars (use current line height). not exposed because it is misleading what it doesn't have an effect on regular layout.
+ // FIXME-WIP: New Drag and Drop API
+ IMGUI_API bool BeginDragDropSource(ImGuiDragDropFlags flags = 0, int mouse_button = 0); // Call when the current item is active. If this return true, you can call SetDragDropPayload() + EndDragDropSource()
+ IMGUI_API bool SetDragDropPayload(const char* type, const void* data, size_t data_size, ImGuiCond cond = 0); // Type is a user defined string of maximum 8 characters. Strings starting with '_' are reserved for dear imgui internal types. Data is copied and held by imgui.
+ IMGUI_API void EndDragDropSource();
+ IMGUI_API bool BeginDragDropTarget(); // Call after submitting an item that may receive an item. If this returns true, you can call AcceptDragDropPayload() + EndDragDropTarget()
+ IMGUI_API const ImGuiPayload* AcceptDragDropPayload(const char* type, ImGuiDragDropFlags flags = 0); // Accept contents of a given type. If ImGuiDragDropFlags_AcceptBeforeDelivery is set you can peek into the payload before the mouse button is released.
+ IMGUI_API void EndDragDropTarget();
+
// FIXME-WIP: New Columns API
IMGUI_API void BeginColumns(const char* id, int count, ImGuiColumnsFlags flags = 0); // setup number of columns. use an identifier to distinguish multiple column sets. close with EndColumns().
IMGUI_API void EndColumns(); // close columns
