commit 50709454b3f62c0c12bf56a89ca8bab90fcd16be
author ocornut <omarcornut@gmail.com> Wed Jun 19 19:02:51 2024 -0700
committer ocornut <omarcornut@gmail.com> Wed Jun 19 19:08:20 2024 -0700
tree 1cb4f35440fdfdcfe1cc344b604de2fd54e17c21
parent 413c056359b2ec7d70725d94bb9c4e522bbbd9f0

Drag and Drop: BeginDragDropSource() with ImGuiDragDropFlags_SourceExtern assume a mouse button being pressed. (#143)

docs/CHANGELOG.txt

diff --git a/docs/CHANGELOG.txt b/docs/CHANGELOG.txt
index e42e5d6..252f954 100644
--- a/docs/CHANGELOG.txt
+++ b/docs/CHANGELOG.txt
@@ -62,9 +62,11 @@
   Added corresponding ImGuiCol_TabSelectedOverline and ImGuiCol_TabDimmedSelectedOverline colors.
 - Drag and Drop: BeginDragDropSource() with ImGuiDragDropFlags_SourceExtern sets
   active id so a multi-frame extern source doesn't interfere with hovered widgets. (#143)
+- Drag and Drop: BeginDragDropSource() with ImGuiDragDropFlags_SourceExtern does not assume
+  a mouse button being pressed. Facilitate implementing cross-context drag and drop. (#143)
 - Drag and Drop: Fixes an issue when elapsing payload would be based on last payload
   frame instead of last drag source frame, which makes a difference if not resubmitting
-  payload every frame.
+  payload every frame. (#143)
 - Examples: GLFW+Vulkan, SDL+Vulkan: handle swap chain resize even without Vulkan
   returning VK_SUBOPTIMAL_KHR, which doesn't seem to happen on Wayland. (#7671)
   [@AndreiNego, @ocornut]

imgui.cpp

diff --git a/imgui.cpp b/imgui.cpp
index 505afa0..01beb6b 100644
--- a/imgui.cpp
+++ b/imgui.cpp
@@ -5136,7 +5136,7 @@
     if (g.DragDropActive)
     {
         bool is_delivered = g.DragDropPayload.Delivery;
-        bool is_elapsed = (g.DragDropSourceFrameCount + 1 < g.FrameCount) && ((g.DragDropSourceFlags & ImGuiDragDropFlags_SourceAutoExpirePayload) || !IsMouseDown(g.DragDropMouseButton));
+        bool is_elapsed = (g.DragDropSourceFrameCount + 1 < g.FrameCount) && ((g.DragDropSourceFlags & ImGuiDragDropFlags_SourceAutoExpirePayload) || g.DragDropMouseButton == -1 || !IsMouseDown(g.DragDropMouseButton));
         if (is_delivered || is_elapsed)
             ClearDragDrop();
     }
@@ -13239,6 +13239,7 @@
         window = NULL;
         source_id = ImHashStr("#SourceExtern");
         source_drag_active = true;
+        mouse_button = g.IO.MouseDown[0] ? 0 : -1;
         KeepAliveID(source_id);
         SetActiveID(source_id, NULL);
     }
@@ -13439,7 +13440,10 @@
         RenderDragDropTargetRect(r, g.DragDropTargetClipRect);
 
     g.DragDropAcceptFrameCount = g.FrameCount;
-    payload.Delivery = was_accepted_previously && !IsMouseDown(g.DragDropMouseButton); // For extern drag sources affecting OS window focus, it's easier to just test !IsMouseDown() instead of IsMouseReleased()
+    if ((g.DragDropSourceFlags & ImGuiDragDropFlags_SourceExtern) && g.DragDropMouseButton == -1)
+        payload.Delivery = was_accepted_previously && (g.DragDropSourceFrameCount < g.FrameCount);
+    else
+        payload.Delivery = was_accepted_previously && !IsMouseDown(g.DragDropMouseButton); // For extern drag sources affecting OS window focus, it's easier to just test !IsMouseDown() instead of IsMouseReleased()
     if (!payload.Delivery && !(flags & ImGuiDragDropFlags_AcceptBeforeDelivery))
         return NULL;