Drag and Drop: Added GetDragDropPayload() to peek directly into the p…

…ayload (if any) from anywhere. (#143)

docs/CHANGELOG.txt

@@ -54,6 +54,7 @@ Other Changes:
   introduced in 1.50 and broken in 1.60. (#1698, #894, #713).
 - 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.
+- Drag and Drop: Added GetDragDropPayload() to peek directly into the payload (if any) from anywhere. (#143)
 - 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.
 

imgui.cpp

@@ -8265,6 +8265,12 @@ const ImGuiPayload* ImGui::AcceptDragDropPayload(const char* type, ImGuiDragDrop
     return &payload;
 }
 
+const ImGuiPayload* ImGui::GetDragDropPayload()
+{
+    ImGuiContext& g = *GImGui;
+    return g.DragDropActive ? &g.DragDropPayload : NULL;
+}
+
 // 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()
 {

imgui.h

@@ -512,10 +512,11 @@ namespace ImGui
     IMGUI_API bool          BeginDragDropSource(ImGuiDragDropFlags flags = 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 size, 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 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();                                                                    // only call EndDragDropTarget() if BeginDragDropTarget() 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()
+    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();                                                            // only call EndDragDropTarget() if BeginDragDropTarget() returns true!
+    IMGUI_API const ImGuiPayload*   GetDragDropPayload();                                                           // peek directly into the current payload from anywhere. may return NULL. use ImGuiPayload::IsDataType() to test for the payload type.
+
     // Clipping
     IMGUI_API void          PushClipRect(const ImVec2& clip_rect_min, const ImVec2& clip_rect_max, bool intersect_with_current_clip_rect);
     IMGUI_API void          PopClipRect();