Tooltip: Testing DragDropWithinSourceOrTarget in BeginTooltipEx() instead of just BeginTooltip() - feel this was an overlook. Added tooltip flags instead of using bool.

docs/TODO.txt

@@ -203,10 +203,12 @@ It's mostly a bunch of personal notes, probably incomplete. Feel free to query i
  - popups: clicking outside (to close popup) and holding shouldn't drag window below.
  - popups: add variant using global identifier similar to Begin/End (#402)
  - popups: border options. richer api like BeginChild() perhaps? (#197)
+
  - tooltip: drag and drop with tooltip near monitor edges lose/changes its last direction instead of locking one. The drag and drop tooltip should always follow without changing direction.
  - tooltip: tooltip that doesn't fit in entire screen seems to lose their "last preferred direction" and may teleport when moving mouse.
  - tooltip: allow to set the width of a tooltip to allow TextWrapped() etc. while keeping the height automatic.
  - tooltip: tooltips with delay timers? or general timer policy? (instantaneous vs timed): IsItemHovered() with timer + implicit aabb-id for items with no ID. (#1485)
+ - tooltip: drag tooltip hovering over source widget with IsItemHovered/SetTooltip flickers.
 
  - menus: calling BeginMenu() twice with a same name doesn't append as Begin() does for regular windows (#1207)
  - menus: menu bars inside modal windows are acting weird.
@@ -252,7 +254,6 @@ It's mostly a bunch of personal notes, probably incomplete. Feel free to query i
  - filters: handle wild-cards (with implicit leading/trailing *), reg-exprs
  - filters: fuzzy matches (may use code at blog.forrestthewoods.com/4cffeed33fdb)
 
- - drag and drop: drag tooltip hovering over source widget with IsItemHovered/SetTooltip flickers.
  - drag and drop: fix/support/options for overlapping drag sources.
  - drag and drop: releasing a drop shows the "..." tooltip for one frame - since e13e598 (#1725)
  - drag and drop: drag source on a group object (would need e.g. an invisible button covering group in EndGroup) https://twitter.com/paniq/status/1121446364909535233

imgui.cpp

@@ -7340,8 +7340,14 @@ void ImGui::SetScrollHereY(float center_y_ratio)
 //-----------------------------------------------------------------------------
 
 void ImGui::BeginTooltip()
+{
+    BeginTooltipEx(ImGuiWindowFlags_None, ImGuiTooltipFlags_None);
+}
+
+void ImGui::BeginTooltipEx(ImGuiWindowFlags extra_flags, ImGuiTooltipFlags tooltip_flags)
 {
     ImGuiContext& g = *GImGui;
+
     if (g.DragDropWithinSourceOrTarget)
     {
         // The default tooltip position is a little offset to give space to see the context menu (it's also clamped within the current viewport/monitor)
@@ -7352,21 +7358,12 @@ void ImGui::BeginTooltip()
         SetNextWindowPos(tooltip_pos);
         SetNextWindowBgAlpha(g.Style.Colors[ImGuiCol_PopupBg].w * 0.60f);
         //PushStyleVar(ImGuiStyleVar_Alpha, g.Style.Alpha * 0.60f); // This would be nice but e.g ColorButton with checkboard has issue with transparent colors :(
-        BeginTooltipEx(0, true);
-    }
-    else
-    {
-        BeginTooltipEx(0, false);
-    }
+        tooltip_flags |= ImGuiTooltipFlags_OverridePreviousTooltip;
     }
 
-// Not exposed publicly as BeginTooltip() because bool parameters are evil. Let's see if other needs arise first.
-void ImGui::BeginTooltipEx(ImGuiWindowFlags extra_flags, bool override_previous_tooltip)
-{
-    ImGuiContext& g = *GImGui;
     char window_name[16];
     ImFormatString(window_name, IM_ARRAYSIZE(window_name), "##Tooltip_%02d", g.TooltipOverrideCount);
-    if (override_previous_tooltip)
+    if (tooltip_flags & ImGuiTooltipFlags_OverridePreviousTooltip)
         if (ImGuiWindow* window = FindWindowByName(window_name))
             if (window->Active)
             {
@@ -7387,11 +7384,7 @@ void ImGui::EndTooltip()
 
 void ImGui::SetTooltipV(const char* fmt, va_list args)
 {
-    ImGuiContext& g = *GImGui;
-    if (g.DragDropWithinSourceOrTarget)
-        BeginTooltip();
-    else
-        BeginTooltipEx(0, true);
+    BeginTooltipEx(0, ImGuiTooltipFlags_OverridePreviousTooltip);
     TextV(fmt, args);
     EndTooltip();
 }

imgui_internal.h

@@ -112,6 +112,7 @@ typedef int ImGuiNextWindowDataFlags;   // -> enum ImGuiNextWindowDataFlags_// F
 typedef int ImGuiSeparatorFlags;        // -> enum ImGuiSeparatorFlags_     // Flags: for SeparatorEx()
 typedef int ImGuiSliderFlags;           // -> enum ImGuiSliderFlags_        // Flags: for SliderBehavior()
 typedef int ImGuiTextFlags;             // -> enum ImGuiTextFlags_          // Flags: for TextEx()
+typedef int ImGuiTooltipFlags;          // -> enum ImGuiTooltipFlags_       // Flags: for BeginTooltipEx()
 
 //-------------------------------------------------------------------------
 // STB libraries includes
@@ -526,6 +527,12 @@ enum ImGuiTextFlags_
     ImGuiTextFlags_NoWidthForLargeClippedText = 1 << 0
 };
 
+enum ImGuiTooltipFlags_
+{
+    ImGuiTooltipFlags_None = 0,
+    ImGuiTooltipFlags_OverridePreviousTooltip = 1 << 0      // Override will clear/ignore previously submitted tooltip (defaults to append)
+};
+
 // FIXME: this is in development, not exposed/functional as a generic feature yet.
 // Horizontal/Vertical enums are fixed to 0/1 so they may be used to index ImVec2
 enum ImGuiLayoutType_
@@ -1106,19 +1113,19 @@ struct ImGuiContext
 
     // Drag and Drop
     bool                    DragDropActive;
-    bool                    DragDropWithinSourceOrTarget;
+    bool                    DragDropWithinSourceOrTarget;       // Set when within a BeginDragDropXXX/EndDragDropXXX block.
     ImGuiDragDropFlags      DragDropSourceFlags;
     int                     DragDropSourceFrameCount;
     int                     DragDropMouseButton;
     ImGuiPayload            DragDropPayload;
-    ImRect                  DragDropTargetRect;
+    ImRect                  DragDropTargetRect;                 // Store rectangle of current target candidate (we favor small targets when overlapping)
     ImGuiID                 DragDropTargetId;
     ImGuiDragDropFlags      DragDropAcceptFlags;
     float                   DragDropAcceptIdCurrRectSurface;    // Target item surface (we resolve overlapping targets by prioritizing the smaller surface)
     ImGuiID                 DragDropAcceptIdCurr;               // Target item id (set at the time of accepting the payload)
     ImGuiID                 DragDropAcceptIdPrev;               // Target item id from previous frame (we need to store this to allow for overlapping drag and drop targets)
     int                     DragDropAcceptFrameCount;           // Last time a target expressed a desire to accept the source
-    ImVector<unsigned char> DragDropPayloadBufHeap;             // We don't expose the ImVector<> directly
+    ImVector<unsigned char> DragDropPayloadBufHeap;             // We don't expose the ImVector<> directly, ImGuiPayload only holds pointer+size
     unsigned char           DragDropPayloadBufLocal[16];        // Local buffer for small payloads
 
     // Tab bars
@@ -1694,7 +1701,7 @@ namespace ImGui
     IMGUI_API void          ClosePopupsOverWindow(ImGuiWindow* ref_window, bool restore_focus_to_window_under_popup);
     IMGUI_API bool          IsPopupOpen(ImGuiID id); // Test for id within current popup stack level (currently begin-ed into); this doesn't scan the whole popup stack!
     IMGUI_API bool          BeginPopupEx(ImGuiID id, ImGuiWindowFlags extra_flags);
-    IMGUI_API void          BeginTooltipEx(ImGuiWindowFlags extra_flags, bool override_previous_tooltip = true);
+    IMGUI_API void          BeginTooltipEx(ImGuiWindowFlags extra_flags, ImGuiTooltipFlags tooltip_flags);
     IMGUI_API ImGuiWindow*  GetTopMostPopupModal();
     IMGUI_API ImVec2        FindBestWindowPosForPopup(ImGuiWindow* window);
     IMGUI_API ImVec2        FindBestWindowPosForPopupEx(const ImVec2& ref_pos, const ImVec2& size, ImGuiDir* last_dir, const ImRect& r_outer, const ImRect& r_avoid, ImGuiPopupPositionPolicy policy = ImGuiPopupPositionPolicy_Default);

imgui_widgets.cpp

@@ -4960,7 +4960,7 @@ void ImGui::ColorTooltip(const char* text, const float* col, ImGuiColorEditFlags
 {
     ImGuiContext& g = *GImGui;
 
-    BeginTooltipEx(0, true);
+    BeginTooltipEx(0, ImGuiTooltipFlags_OverridePreviousTooltip);
     const char* text_end = text ? FindRenderedTextEnd(text, NULL) : text;
     if (text_end > text)
     {