Internals: track WasSelected/WasSoleSelected data for ActiveId. (#8337)

imgui.cpp

@@ -4234,6 +4234,7 @@ ImGuiContext::ImGuiContext(ImFontAtlas* shared_font_atlas)
     ActiveIdIsAlive = 0;
     ActiveIdTimer = 0.0f;
     ActiveIdIsJustActivated = false;
+    ActiveIdWasSelected = ActiveIdWasSoleSelected = false;
     ActiveIdAllowOverlap = false;
     ActiveIdNoClearOnFocusLoss = false;
     ActiveIdHasBeenPressedBefore = false;
@@ -4250,6 +4251,7 @@ ImGuiContext::ImGuiContext(ImFontAtlas* shared_font_atlas)
     memset(&ActiveIdValueOnActivation, 0, sizeof(ActiveIdValueOnActivation));
     LastActiveId = 0;
     LastActiveIdTimer = 0.0f;
+    LastActiveIdWasSelected = LastActiveIdWasSoleSelected = false;
 
     LastKeyboardKeyPressTime = LastKeyModsChangeTime = LastKeyModsChangeFromNoneTime = -1.0;
 
@@ -5629,6 +5631,11 @@ void ImGui::NewFrame()
     // Update ActiveId data (clear reference to active widget if the widget isn't alive anymore)
     if (g.ActiveId)
         g.ActiveIdTimer += g.IO.DeltaTime;
+    if (g.ActiveId && g.ActiveId == g.LastActiveId)
+    {
+        g.LastActiveIdWasSelected = g.ActiveIdWasSelected;
+        g.LastActiveIdWasSoleSelected = g.ActiveIdWasSoleSelected;
+    }
     g.LastActiveIdTimer += g.IO.DeltaTime;
     g.ActiveIdPreviousFrame = g.ActiveId;
     g.ActiveIdIsAlive = 0;

imgui_internal.h

@@ -1940,6 +1940,7 @@ struct IMGUI_API ImGuiMultiSelectTempData
     bool                    NavIdPassedBy;
     bool                    RangeSrcPassedBy;   // Set by the item that matches RangeSrcItem.
     bool                    RangeDstPassedBy;   // Set by the item that matches NavJustMovedToId when IsSetRange is set.
+    bool                    IsSoleOrUnknownSelectionSize;
 
     ImGuiMultiSelectTempData()  { Clear(); }
     void Clear()            { size_t io_sz = sizeof(IO); ClearIO(); memset((void*)(&IO + 1), 0, sizeof(*this) - io_sz); } // Zero-clear except IO as we preserve IO.Requests[] buffer allocation.
@@ -2281,6 +2282,8 @@ struct ImGuiContext
     ImGuiID                 ActiveIdIsAlive;                    // Active widget has been seen this frame (we can't use a bool as the ActiveId may change within the frame)
     float                   ActiveIdTimer;
     bool                    ActiveIdIsJustActivated;            // Set at the time of activation for one frame
+    bool                    ActiveIdWasSelected;                // Active ID was selected at the time of activating
+    bool                    ActiveIdWasSoleSelected;            // Active ID was sole selection at the time of activating
     bool                    ActiveIdAllowOverlap;               // Active widget allows another widget to steal active id (generally for overlapping widgets, but not always)
     bool                    ActiveIdNoClearOnFocusLoss;         // Disable losing active id if the active id window gets unfocused.
     bool                    ActiveIdHasBeenPressedBefore;       // Track whether the active id led to a press (this is to allow changing between PressOnClick and PressOnRelease without pressing twice). Used by range_select branch.
@@ -2297,6 +2300,8 @@ struct ImGuiContext
     ImGuiDataTypeStorage    ActiveIdValueOnActivation;          // Backup of initial value at the time of activation. ONLY SET BY SPECIFIC WIDGETS: DragXXX and SliderXXX.
     ImGuiID                 LastActiveId;                       // Store the last non-zero ActiveId, useful for animation.
     float                   LastActiveIdTimer;                  // Store the last non-zero ActiveId timer since the beginning of activation, useful for animation.
+    bool                    LastActiveIdWasSelected;
+    bool                    LastActiveIdWasSoleSelected;
 
     // Key/Input Ownership + Shortcut Routing system
     // - The idea is that instead of "eating" a given key, we can link to an owner.

imgui_widgets.cpp

@@ -7489,6 +7489,11 @@ bool ImGui::Selectable(const char* label, bool selected, ImGuiSelectableFlags fl
 
     if (selected != was_selected)
         g.LastItemData.StatusFlags |= ImGuiItemStatusFlags_ToggledSelection;
+    if (g.ActiveId == id && g.ActiveIdIsJustActivated)
+    {
+        g.ActiveIdWasSelected = was_selected;
+        g.ActiveIdWasSoleSelected = was_selected && (!is_multi_select || g.CurrentMultiSelect->IsSoleOrUnknownSelectionSize);
+    }
 
     // Render
     if (is_visible)
@@ -8116,6 +8121,7 @@ ImGuiMultiSelectIO* ImGui::BeginMultiSelect(ImGuiMultiSelectFlags flags, int sel
             storage->LastSelectionSize = 0;
     }
     ms->LoopRequestSetAll = request_select_all ? 1 : request_clear ? 0 : -1;
+    ms->IsSoleOrUnknownSelectionSize = (storage->LastSelectionSize == 1) || (storage->LastSelectionSize == -1);
     //ms->PrevSubmittedItem = ImGuiSelectionUserData_Invalid;
 
     if (g.DebugLogFlags & ImGuiDebugLogFlags_EventSelection)