Demo: Added 'Examples->Fullscreen Window' demo. (#3789) + repack and zero-clear ImDrawData.

docs/CHANGELOG.txt

@@ -78,6 +78,7 @@ Other Changes:
 - Log/Capture: Improved the ascii look of various widgets, making large dumps more easily human readable.
 - ImDrawList: Fixed AddCircle()/AddCircleFilled() with (rad > 0.0f && rad < 1.0f && num_segments == 0). (#3738)
   Would lead to a buffer read overflow.
+- Demo: Added 'Examples->Fullscreen Window' demo. (#3789)
 - Backends: Win32: Dynamically loading XInput DLL instead of linking with it, facilite compiling with
   old WindowSDK versions or running on Windows 7. (#3646, #3645, #3248, #2716) [@Demonese]
 - Backends: Vulkan: Add support for custom Vulkan function loader and VK_NO_PROTOTYPES. (#3759, #3227) [@Hossein-Noroozpour]

examples/example_emscripten_wgpu/main.cpp

@@ -75,7 +75,7 @@ int main(int, char**)
     //ImGui::StyleColorsClassic();
 
     // Setup Platform/Renderer backends
-    ImGui_ImplGlfw_InitForVulkan(window, true);
+    ImGui_ImplGlfw_InitForWebGPU(window, true);
     ImGui_ImplWGPU_Init(wgpu_device, 3, WGPUTextureFormat_RGBA8Unorm);
 
     // Load Fonts

imgui.h

@@ -2461,18 +2461,17 @@ struct ImDrawList
 struct ImDrawData
 {
     bool            Valid;                  // Only valid after Render() is called and before the next NewFrame() is called.
-    ImDrawList**    CmdLists;               // Array of ImDrawList* to render. The ImDrawList are owned by ImGuiContext and only pointed to from here.
     int             CmdListsCount;          // Number of ImDrawList* to render
     int             TotalIdxCount;          // For convenience, sum of all ImDrawList's IdxBuffer.Size
     int             TotalVtxCount;          // For convenience, sum of all ImDrawList's VtxBuffer.Size
+    ImDrawList**    CmdLists;               // Array of ImDrawList* to render. The ImDrawList are owned by ImGuiContext and only pointed to from here.
     ImVec2          DisplayPos;             // Upper-left position of the viewport to render (== upper-left of the orthogonal projection matrix to use)
     ImVec2          DisplaySize;            // Size of the viewport to render (== io.DisplaySize for the main viewport) (DisplayPos + DisplaySize == lower-right of the orthogonal projection matrix to use)
     ImVec2          FramebufferScale;       // Amount of pixels for each unit of DisplaySize. Based on io.DisplayFramebufferScale. Generally (1,1) on normal display, (2,2) on OSX with Retina display.
 
     // Functions
-    ImDrawData()    { Valid = false; Clear(); }
+    ImDrawData()    { Clear(); }
-    ~ImDrawData()   { Clear(); }
+    void Clear()    { memset(this, 0, sizeof(*this)); }     // The ImDrawList are owned by ImGuiContext!
-    void Clear()    { Valid = false; CmdLists = NULL; CmdListsCount = TotalVtxCount = TotalIdxCount = 0; DisplayPos = DisplaySize = FramebufferScale = ImVec2(0.f, 0.f); } // The ImDrawList are owned by ImGuiContext!
     IMGUI_API void  DeIndexAllBuffers();                    // Helper to convert all buffers from indexed to non-indexed, in case you cannot render indexed. Note: this is slow and most likely a waste of resources. Always prefer indexed rendering!
     IMGUI_API void  ScaleClipRects(const ImVec2& fb_scale); // Helper to scale the ClipRect field of each ImDrawCmd. Use if your final output buffer is at a different scale than Dear ImGui expects, or if there is a difference between your window resolution and framebuffer resolution.
 };

imgui_demo.cpp

@@ -63,8 +63,9 @@ Index of this file:
 // [SECTION] Example App: Long Text / ShowExampleAppLongText()
 // [SECTION] Example App: Auto Resize / ShowExampleAppAutoResize()
 // [SECTION] Example App: Constrained Resize / ShowExampleAppConstrainedResize()
-// [SECTION] Example App: Simple Overlay / ShowExampleAppSimpleOverlay()
+// [SECTION] Example App: Simple overlay / ShowExampleAppSimpleOverlay()
-// [SECTION] Example App: Manipulating Window Titles / ShowExampleAppWindowTitles()
+// [SECTION] Example App: Fullscreen window / ShowExampleAppFullscreen()
+// [SECTION] Example App: Manipulating window titles / ShowExampleAppWindowTitles()
 // [SECTION] Example App: Custom Rendering using ImDrawList API / ShowExampleAppCustomRendering()
 // [SECTION] Example App: Documents Handling / ShowExampleAppDocuments()
 
@@ -168,6 +169,7 @@ static void ShowExampleAppLongText(bool* p_open);
 static void ShowExampleAppAutoResize(bool* p_open);
 static void ShowExampleAppConstrainedResize(bool* p_open);
 static void ShowExampleAppSimpleOverlay(bool* p_open);
+static void ShowExampleAppFullscreen(bool* p_open);
 static void ShowExampleAppWindowTitles(bool* p_open);
 static void ShowExampleAppCustomRendering(bool* p_open);
 static void ShowExampleMenuFile();
@@ -259,6 +261,7 @@ void ImGui::ShowDemoWindow(bool* p_open)
     static bool show_app_auto_resize = false;
     static bool show_app_constrained_resize = false;
     static bool show_app_simple_overlay = false;
+    static bool show_app_fullscreen = false;
     static bool show_app_window_titles = false;
     static bool show_app_custom_rendering = false;
 
@@ -273,6 +276,7 @@ void ImGui::ShowDemoWindow(bool* p_open)
     if (show_app_auto_resize)         ShowExampleAppAutoResize(&show_app_auto_resize);
     if (show_app_constrained_resize)  ShowExampleAppConstrainedResize(&show_app_constrained_resize);
     if (show_app_simple_overlay)      ShowExampleAppSimpleOverlay(&show_app_simple_overlay);
+    if (show_app_fullscreen)          ShowExampleAppFullscreen(&show_app_fullscreen);
     if (show_app_window_titles)       ShowExampleAppWindowTitles(&show_app_window_titles);
     if (show_app_custom_rendering)    ShowExampleAppCustomRendering(&show_app_custom_rendering);
 
@@ -354,6 +358,7 @@ void ImGui::ShowDemoWindow(bool* p_open)
             ImGui::MenuItem("Auto-resizing window", NULL, &show_app_auto_resize);
             ImGui::MenuItem("Constrained-resizing window", NULL, &show_app_constrained_resize);
             ImGui::MenuItem("Simple overlay", NULL, &show_app_simple_overlay);
+            ImGui::MenuItem("Fullscreen window", NULL, &show_app_fullscreen);
             ImGui::MenuItem("Manipulating window titles", NULL, &show_app_window_titles);
             ImGui::MenuItem("Custom rendering", NULL, &show_app_custom_rendering);
             ImGui::MenuItem("Documents", NULL, &show_app_documents);
@@ -6971,7 +6976,7 @@ static void ShowExampleAppConstrainedResize(bool* p_open)
 }
 
 //-----------------------------------------------------------------------------
-// [SECTION] Example App: Simple Overlay / ShowExampleAppSimpleOverlay()
+// [SECTION] Example App: Simple overlay / ShowExampleAppSimpleOverlay()
 //-----------------------------------------------------------------------------
 
 // Demonstrate creating a simple static window with no decoration
@@ -7012,6 +7017,30 @@ static void ShowExampleAppSimpleOverlay(bool* p_open)
     ImGui::End();
 }
 
+//-----------------------------------------------------------------------------
+// [SECTION] Example App: Fullscreen window / ShowExampleAppFullscreen()
+//-----------------------------------------------------------------------------
+
+// Demonstrate creating a window covering the entire screen/viewport
+static void ShowExampleAppFullscreen(bool* p_open)
+{
+    ImGuiIO& io = ImGui::GetIO();
+    static ImGuiWindowFlags flags = ImGuiWindowFlags_NoDecoration | ImGuiWindowFlags_NoMove | ImGuiWindowFlags_NoResize | ImGuiWindowFlags_NoSavedSettings;
+    ImGui::SetNextWindowPos(ImVec2(0, 0));
+    ImGui::SetNextWindowSize(io.DisplaySize);
+    if (ImGui::Begin("Example: Fullscreen window", p_open, flags))
+    {
+        ImGui::CheckboxFlags("ImGuiWindowFlags_NoBackground", &flags, ImGuiWindowFlags_NoBackground);
+        ImGui::CheckboxFlags("ImGuiWindowFlags_NoDecoration", &flags, ImGuiWindowFlags_NoDecoration);
+        ImGui::Indent();
+        ImGui::CheckboxFlags("ImGuiWindowFlags_NoTitleBar", &flags, ImGuiWindowFlags_NoTitleBar);
+        ImGui::CheckboxFlags("ImGuiWindowFlags_NoCollapse", &flags, ImGuiWindowFlags_NoCollapse);
+        ImGui::CheckboxFlags("ImGuiWindowFlags_NoScrollbar", &flags, ImGuiWindowFlags_NoScrollbar);
+        ImGui::Unindent();
+    }
+    ImGui::End();
+}
+
 //-----------------------------------------------------------------------------
 // [SECTION] Example App: Manipulating Window Titles / ShowExampleAppWindowTitles()
 //-----------------------------------------------------------------------------