Added IsWindowAppearing().

imgui.cpp

@@ -1789,6 +1789,7 @@ ImGuiWindow::ImGuiWindow(const char* name)
     Accessed = false;
     Collapsed = false;
     SkipItems = false;
+    Appearing = false;
     BeginCount = 0;
     PopupId = 0;
     AutoFitFramesX = AutoFitFramesY = -1;
@@ -3976,13 +3977,15 @@ bool ImGui::Begin(const char* name, bool* p_open, const ImVec2& size_on_first_us
     }
 
     const bool window_appearing_after_being_hidden = (window->HiddenFrames == 1);
+    window->Appearing = (!window_was_active || window_appearing_after_being_hidden);
 
     // Process SetNextWindow***() calls
     bool window_pos_set_by_api = false, window_size_set_by_api = false;
     if (g.SetNextWindowPosCond)
     {
         const ImVec2 backup_cursor_pos = window->DC.CursorPos;                  // FIXME: not sure of the exact reason of this saving/restore anymore :( need to look into that.
-        if (!window_was_active || window_appearing_after_being_hidden) window->SetWindowPosAllowFlags |= ImGuiCond_Appearing;
+        if (window->Appearing) 
+            window->SetWindowPosAllowFlags |= ImGuiCond_Appearing;
         window_pos_set_by_api = (window->SetWindowPosAllowFlags & g.SetNextWindowPosCond) != 0;
         if (window_pos_set_by_api && ImLengthSqr(g.SetNextWindowPosVal - ImVec2(-FLT_MAX,-FLT_MAX)) < 0.001f)
         {
@@ -3998,7 +4001,8 @@ bool ImGui::Begin(const char* name, bool* p_open, const ImVec2& size_on_first_us
     }
     if (g.SetNextWindowSizeCond)
     {
-        if (!window_was_active || window_appearing_after_being_hidden) window->SetWindowSizeAllowFlags |= ImGuiCond_Appearing;
+        if (window->Appearing) 
+            window->SetWindowSizeAllowFlags |= ImGuiCond_Appearing;
         window_size_set_by_api = (window->SetWindowSizeAllowFlags & g.SetNextWindowSizeCond) != 0;
         SetWindowSize(window, g.SetNextWindowSizeVal, g.SetNextWindowSizeCond);
         g.SetNextWindowSizeCond = 0;
@@ -4014,13 +4018,14 @@ bool ImGui::Begin(const char* name, bool* p_open, const ImVec2& size_on_first_us
     }
     if (g.SetNextWindowCollapsedCond)
     {
-        if (!window_was_active || window_appearing_after_being_hidden) window->SetWindowCollapsedAllowFlags |= ImGuiCond_Appearing;
+        if (window->Appearing)
+            window->SetWindowCollapsedAllowFlags |= ImGuiCond_Appearing;
         SetWindowCollapsed(window, g.SetNextWindowCollapsedVal, g.SetNextWindowCollapsedCond);
         g.SetNextWindowCollapsedCond = 0;
     }
     if (g.SetNextWindowFocus)
     {
-        ImGui::SetWindowFocus();
+        SetWindowFocus();
         g.SetNextWindowFocus = false;
     }
 
@@ -5073,7 +5078,14 @@ void ImGui::SetWindowCollapsed(bool collapsed, ImGuiCond cond)
 
 bool ImGui::IsWindowCollapsed()
 {
-    return GImGui->CurrentWindow->Collapsed;
+    ImGuiWindow* window = GetCurrentWindowRead();
+    return window->Collapsed;
+}
+
+bool ImGui::IsWindowAppearing()
+{
+    ImGuiWindow* window = GetCurrentWindowRead();
+    return window->Appearing;
 }
 
 void ImGui::SetWindowCollapsed(const char* name, bool collapsed, ImGuiCond cond)

imgui.h

@@ -149,6 +149,7 @@ namespace ImGui
     IMGUI_API float         GetWindowWidth();
     IMGUI_API float         GetWindowHeight();
     IMGUI_API bool          IsWindowCollapsed();
+    IMGUI_API bool          IsWindowAppearing();
     IMGUI_API void          SetWindowFontScale(float scale);                                    // per-window font scale. Adjust IO.FontGlobalScale if you want to scale all windows
 
     IMGUI_API void          SetNextWindowPos(const ImVec2& pos, ImGuiCond cond = 0);            // set next window position. call before Begin()

imgui_internal.h

@@ -674,7 +674,8 @@ struct IMGUI_API ImGuiWindow
     bool                    WasActive;
     bool                    Accessed;                           // Set to true when any widget access the current window
     bool                    Collapsed;                          // Set when collapsing window to become only title-bar
-    bool                    SkipItems;                          // == Visible && !Collapsed
+    bool                    SkipItems;                          // Set when items can safely be all clipped (e.g. window not visible or collapsed)
+    bool                    Appearing;                          // Set during the frame where the window is appearing (or re-appearing)
     int                     BeginCount;                         // Number of Begin() during the current frame (generally 0 or 1, 1+ if appending via multiple Begin/End pairs)
     ImGuiID                 PopupId;                            // ID in the popup stack when this window is used as a popup/menu (because we use generic Name/ID for recycling)
     int                     AutoFitFramesX, AutoFitFramesY;
@@ -701,7 +702,6 @@ struct IMGUI_API ImGuiWindow
     ImGuiWindow*            RootWindow;                         // Generally point to ourself. If we are a child window, this is pointing to the first non-child parent window.
     ImGuiWindow*            RootNonPopupWindow;                 // Generally point to ourself. Used to display TitleBgActive color and for selecting which window to use for NavWindowing
 
-
     // Navigation / Focus
     int                     FocusIdxAllCounter;                 // Start at -1 and increase as assigned via FocusItemRegister()
     int                     FocusIdxTabCounter;                 // (same, but only count widgets which you can Tab through)