Begin: WIP consistent Begin/End behavior, BeginTooltip API (one issue with BeginDragDropSource)

imgui.cpp

@@ -4153,13 +4153,15 @@ void ImGui::UpdateDebugToolItemPicker()
             g.DebugItemPickerActive = false;
         }
         ImGui::SetNextWindowBgAlpha(0.60f);
-        ImGui::BeginTooltip();
+        if (ImGui::BeginTooltip())
+        {
             ImGui::Text("HoveredId: 0x%08X", hovered_id);
             ImGui::Text("Press ESC to abort picking.");
             ImGui::TextColored(GetStyleColorVec4(hovered_id ? ImGuiCol_Text : ImGuiCol_TextDisabled), "Click to break in debugger!");
             ImGui::EndTooltip();
         }
     }
+}
 
 void ImGui::Initialize(ImGuiContext* context)
 {
@@ -8540,12 +8542,12 @@ void ImGui::SetScrollHereY(float center_y_ratio)
 // [SECTION] TOOLTIPS
 //-----------------------------------------------------------------------------
 
-void ImGui::BeginTooltip()
+bool ImGui::BeginTooltip()
 {
-    BeginTooltipEx(ImGuiWindowFlags_None, ImGuiTooltipFlags_None);
+    return BeginTooltipEx(ImGuiWindowFlags_None, ImGuiTooltipFlags_None);
 }
 
-void ImGui::BeginTooltipEx(ImGuiWindowFlags extra_flags, ImGuiTooltipFlags tooltip_flags)
+bool ImGui::BeginTooltipEx(ImGuiWindowFlags extra_flags, ImGuiTooltipFlags tooltip_flags)
 {
     ImGuiContext& g = *GImGui;
 
@@ -8575,8 +8577,10 @@ void ImGui::BeginTooltipEx(ImGuiWindowFlags extra_flags, ImGuiTooltipFlags toolt
             }
     ImGuiWindowFlags flags = ImGuiWindowFlags_Tooltip | ImGuiWindowFlags_NoInputs | ImGuiWindowFlags_NoTitleBar | ImGuiWindowFlags_NoMove | ImGuiWindowFlags_NoResize | ImGuiWindowFlags_NoSavedSettings | ImGuiWindowFlags_AlwaysAutoResize | ImGuiWindowFlags_NoDocking;
     bool ret = Begin(window_name, NULL, flags | extra_flags);
-    // FIXME-NEWBEGIN
+    // FIXME-NEWBEGIN: adding a bool to API...
-    IM_ASSERT(ret);
+    //IM_UNUSED(ret);
+    //IM_ASSERT(ret);
+    return ret;
 }
 
 void ImGui::EndTooltip()
@@ -8587,7 +8591,8 @@ void ImGui::EndTooltip()
 
 void ImGui::SetTooltipV(const char* fmt, va_list args)
 {
-    BeginTooltipEx(0, ImGuiTooltipFlags_OverridePreviousTooltip);
+    if (!BeginTooltipEx(0, ImGuiTooltipFlags_OverridePreviousTooltip))
+        return;
     TextV(fmt, args);
     EndTooltip();
 }
@@ -10381,7 +10386,9 @@ bool ImGui::BeginDragDropSource(ImGuiDragDropFlags flags)
         {
             // Target can request the Source to not display its tooltip (we use a dedicated flag to make this request explicit)
             // We unfortunately can't just modify the source flags and skip the call to BeginTooltip, as caller may be emitting contents.
-            BeginTooltip();
+            bool ret = BeginTooltip(); // FIXME-NEWBEGIN: problematic
+            IM_UNUSED(ret);
+            IM_ASSERT(ret);
             if (g.DragDropAcceptIdPrev && (g.DragDropAcceptFlags & ImGuiDragDropFlags_AcceptNoPreviewTooltip))
             {
                 ImGuiWindow* tooltip_window = g.CurrentWindow;
@@ -15745,9 +15752,8 @@ static void RenderViewportsThumbnails()
 static void MetricsHelpMarker(const char* desc)
 {
     ImGui::TextDisabled("(?)");
-    if (ImGui::IsItemHovered())
+    if (ImGui::IsItemHovered() && ImGui::BeginTooltip())
     {
-        ImGui::BeginTooltip();
         ImGui::PushTextWrapPos(ImGui::GetFontSize() * 35.0f);
         ImGui::TextUnformatted(desc);
         ImGui::PopTextWrapPos();

imgui.h

@@ -624,7 +624,7 @@ namespace ImGui
 
     // Tooltips
     // - Tooltip are windows following the mouse which do not take focus away.
-    IMGUI_API void          BeginTooltip();                                                     // begin/append a tooltip window. to create full-featured tooltip (with any kind of items).
+    IMGUI_API bool          BeginTooltip();                                                     // begin/append a tooltip window. to create full-featured tooltip (with any kind of items).
     IMGUI_API void          EndTooltip();
     IMGUI_API void          SetTooltip(const char* fmt, ...) IM_FMTARGS(1);                     // set a text-only tooltip, typically use with ImGui::IsItemHovered(). override any previous call to SetTooltip().
     IMGUI_API void          SetTooltipV(const char* fmt, va_list args) IM_FMTLIST(1);

imgui_demo.cpp

@@ -179,9 +179,8 @@ static void ShowExampleMenuFile();
 static void HelpMarker(const char* desc)
 {
     ImGui::TextDisabled("(?)");
-    if (ImGui::IsItemHovered())
+    if (ImGui::IsItemHovered() && ImGui::BeginTooltip())
     {
-        ImGui::BeginTooltip();
         ImGui::PushTextWrapPos(ImGui::GetFontSize() * 35.0f);
         ImGui::TextUnformatted(desc);
         ImGui::PopTextWrapPos();
@@ -621,9 +620,8 @@ static void ShowDemoWindowWidgets()
 
         ImGui::SameLine();
         ImGui::Text("- or me");
-        if (ImGui::IsItemHovered())
+        if (ImGui::IsItemHovered() && ImGui::BeginTooltip())
         {
-            ImGui::BeginTooltip();
             ImGui::Text("I am a fancy tooltip");
             static float arr[] = { 0.6f, 0.1f, 1.0f, 0.5f, 0.92f, 0.1f, 0.2f };
             ImGui::PlotLines("Curve", arr, IM_ARRAYSIZE(arr));
@@ -1006,9 +1004,8 @@ static void ShowDemoWindowWidgets()
             ImVec4 tint_col = ImVec4(1.0f, 1.0f, 1.0f, 1.0f);   // No tint
             ImVec4 border_col = ImVec4(1.0f, 1.0f, 1.0f, 0.5f); // 50% opaque white
             ImGui::Image(my_tex_id, ImVec2(my_tex_w, my_tex_h), uv_min, uv_max, tint_col, border_col);
-            if (ImGui::IsItemHovered())
+            if (ImGui::IsItemHovered() && ImGui::BeginTooltip())
             {
-                ImGui::BeginTooltip();
                 float region_sz = 32.0f;
                 float region_x = io.MousePos.x - pos.x - region_sz * 0.5f;
                 float region_y = io.MousePos.y - pos.y - region_sz * 0.5f;
@@ -5682,9 +5679,8 @@ static void NodeFont(ImFont* font)
                 draw_list->AddRect(cell_p1, cell_p2, glyph ? IM_COL32(255, 255, 255, 100) : IM_COL32(255, 255, 255, 50));
                 if (glyph)
                     font->RenderChar(draw_list, cell_size, cell_p1, glyph_col, (ImWchar)(base + n));
-                if (glyph && ImGui::IsMouseHoveringRect(cell_p1, cell_p2))
+                if (glyph && ImGui::IsMouseHoveringRect(cell_p1, cell_p2) && ImGui::BeginTooltip())
                 {
-                    ImGui::BeginTooltip();
                     ImGui::Text("Codepoint: U+%04X", base + n);
                     ImGui::Separator();
                     ImGui::Text("Visible: %d", glyph->Visible);
@@ -5914,7 +5910,8 @@ void ImGui::ShowStyleEditor(ImGuiStyle* ref)
             if (ImGui::IsItemActive())
             {
                 ImGui::SetNextWindowPos(ImGui::GetCursorScreenPos());
-                ImGui::BeginTooltip();
+                if (ImGui::BeginTooltip())
+                {
                     ImVec2 p = ImGui::GetCursorScreenPos();
                     ImDrawList* draw_list = ImGui::GetWindowDrawList();
                     float RAD_MIN = 10.0f, RAD_MAX = 80.0f;
@@ -5928,6 +5925,7 @@ void ImGui::ShowStyleEditor(ImGuiStyle* ref)
                     ImGui::Dummy(ImVec2(off_x, RAD_MAX * 2.0f));
                     ImGui::EndTooltip();
                 }
+            }
             ImGui::SameLine();
             HelpMarker("When drawing circle primitives with \"num_segments == 0\" tesselation will be calculated automatically.");
 

imgui_internal.h

@@ -2449,7 +2449,7 @@ namespace ImGui
     IMGUI_API void          ClosePopupsOverWindow(ImGuiWindow* ref_window, bool restore_focus_to_window_under_popup);
     IMGUI_API bool          IsPopupOpen(ImGuiID id, ImGuiPopupFlags popup_flags);
     IMGUI_API bool          BeginPopupEx(ImGuiID id, ImGuiWindowFlags extra_flags);
-    IMGUI_API void          BeginTooltipEx(ImGuiWindowFlags extra_flags, ImGuiTooltipFlags tooltip_flags);
+    IMGUI_API bool          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);

imgui_widgets.cpp

@@ -5353,7 +5353,8 @@ void ImGui::ColorTooltip(const char* text, const float* col, ImGuiColorEditFlags
 {
     ImGuiContext& g = *GImGui;
 
-    BeginTooltipEx(0, ImGuiTooltipFlags_OverridePreviousTooltip);
+    if (!BeginTooltipEx(0, ImGuiTooltipFlags_OverridePreviousTooltip))
+        return;
     const char* text_end = text ? FindRenderedTextEnd(text, NULL) : text;
     if (text_end > text)
     {