cpu start

backends/imgui_impl_cpu.h

@@ -0,0 +1,81 @@
+// dear imgui: CPU framebuffer renderer backend
+// (supports caller-owned framebuffers/textures in generic packed pixel formats)
+//
+// Implemented features:
+//  [X] Renderer: User texture binding. Use 'ImGui_ImplCPU_Texture*' as texture identifier.
+//  [X] Renderer: Large meshes support (64k+ vertices) even with 16-bit indices.
+//  [X] Renderer: Texture updates support for dynamic font atlas.
+
+#pragma once
+#ifndef IMGUI_DISABLE
+#include "imgui.h"
+
+struct ImGui_ImplCPU_PixelFormat;
+typedef ImU32 (*ImGui_ImplCPU_MapColorFn)(const ImGui_ImplCPU_PixelFormat* format, unsigned char r, unsigned char g, unsigned char b, unsigned char a);
+
+struct ImGui_ImplCPU_PixelFormat
+{
+    int                         BitsPerPixel;
+    int                         BytesPerPixel;
+    ImU32                       Rmask;
+    ImU32                       Gmask;
+    ImU32                       Bmask;
+    ImU32                       Amask;
+    ImU8                        Rshift;
+    ImU8                        Gshift;
+    ImU8                        Bshift;
+    ImU8                        Ashift;
+    ImU8                        Rloss;
+    ImU8                        Gloss;
+    ImU8                        Bloss;
+    ImU8                        Aloss;
+    const ImU32*                Palette;        // Optional palette entries stored as IM_COL32(r, g, b, a).
+    int                         PaletteSize;    // Number of palette entries, or 0 when Palette is unused.
+    ImGui_ImplCPU_MapColorFn    MapColorFn;     // Optional indexed/paletted mapping override. Return a raw packed pixel value.
+};
+
+enum ImGui_ImplCPU_BuiltinFormat
+{
+    ImGui_ImplCPU_BuiltinFormat_RGBA8888 = 0,
+    ImGui_ImplCPU_BuiltinFormat_BGRA8888,
+    ImGui_ImplCPU_BuiltinFormat_ARGB8888,
+    ImGui_ImplCPU_BuiltinFormat_ABGR8888,
+    ImGui_ImplCPU_BuiltinFormat_RGB565,
+    ImGui_ImplCPU_BuiltinFormat_ARGB1555,
+    ImGui_ImplCPU_BuiltinFormat_RGBA4444,
+    ImGui_ImplCPU_BuiltinFormat_RGB888,
+    ImGui_ImplCPU_BuiltinFormat_BGR888,
+    ImGui_ImplCPU_BuiltinFormat_Alpha8,
+    ImGui_ImplCPU_BuiltinFormat_COUNT
+};
+
+struct ImGui_ImplCPU_Framebuffer
+{
+    unsigned char*                  Pixels;
+    int                             Width;
+    int                             Height;
+    int                             Pitch;
+    const ImGui_ImplCPU_PixelFormat* Format;    // Optional. Defaults to ImGui_ImplCPU_BuiltinFormat_RGBA8888.
+};
+
+struct ImGui_ImplCPU_Texture
+{
+    const unsigned char*            Pixels;
+    int                             Width;
+    int                             Height;
+    int                             Pitch;
+    const ImGui_ImplCPU_PixelFormat* Format;    // Optional. Defaults to ImGui_ImplCPU_BuiltinFormat_RGBA8888.
+};
+
+// Follow "Getting Started" link and check examples/ folder to learn about using backends!
+IMGUI_IMPL_API const ImGui_ImplCPU_PixelFormat* ImGui_ImplCPU_GetBuiltinPixelFormat(ImGui_ImplCPU_BuiltinFormat format);
+IMGUI_IMPL_API bool     ImGui_ImplCPU_Init();
+IMGUI_IMPL_API void     ImGui_ImplCPU_Shutdown();
+IMGUI_IMPL_API void     ImGui_ImplCPU_NewFrame();
+IMGUI_IMPL_API void     ImGui_ImplCPU_RenderDrawData(ImDrawData* draw_data, ImGui_ImplCPU_Framebuffer* framebuffer);
+
+// (Advanced) Use e.g. if you need to precisely control the timing of texture updates
+// by setting ImDrawData::Textures = nullptr to handle this manually.
+IMGUI_IMPL_API void     ImGui_ImplCPU_UpdateTexture(ImTextureData* tex);
+
+#endif // #ifndef IMGUI_DISABLE

docs/BACKENDS.md

@@ -84,6 +84,7 @@ List of Platforms Backends:
 
 List of Renderer Backends:
 
+    imgui_impl_cpu.cpp          ; Generic packed-pixel CPU framebuffer renderer (RGBA/BGRA/RGB565/indexed, etc. see example_sdl2_cpu, example_apple_cpu)
     imgui_impl_dx9.cpp          ; DirectX9
     imgui_impl_dx10.cpp         ; DirectX10
     imgui_impl_dx11.cpp         ; DirectX11
@@ -105,7 +106,7 @@ List of high-level Frameworks Backends (combining Platform + Renderer):
     imgui_impl_null.cpp
 
 Emscripten is also supported!
-The SDL2+GL, SDL3+GL, SDL2+Surface, SDL3+Surface, GLFW+GL and GLFW+WebGPU examples are all ready to build and run with Emscripten.
+The SDL2+CPU, SDL2+GL, SDL3+GL, SDL2+Surface, SDL3+Surface, GLFW+GL and GLFW+WebGPU examples are all ready to build and run with Emscripten.
 
 ### Recommended Backends
 

docs/EXAMPLES.md

@@ -71,6 +71,11 @@ OSX + OpenGL2 example. <BR>
 (NB: imgui_impl_osx.mm is currently not as feature complete as other platforms backends.
  You may prefer to use the GLFW Or SDL backends, which will also support Windows and Linux.)
 
+[example_apple_cpu/](https://github.com/ocornut/imgui/blob/master/examples/example_apple_cpu/) <BR>
+OSX + CPU framebuffer example. <BR>
+= main.mm + imgui_impl_osx.mm + imgui_impl_cpu.cpp <BR>
+This is a native Cocoa example, renders to a native BGRA framebuffer, and does not use SDL.<BR>
+
 [example_glfw_wgpu/](https://github.com/ocornut/imgui/blob/master/examples/example_glfw_wgpu/) <BR>
 GLFW + WebGPU example. Supports Emscripten (web), Dawn (native), WGPU (native). <BR>
 = main.cpp + imgui_impl_glfw.cpp + imgui_impl_wgpu.cpp
@@ -150,6 +155,12 @@ SDL2 (Win32, Mac, Linux, etc.) + SDL_Surface CPU renderer example.<BR>
 = main.cpp + imgui_impl_sdl2.cpp + imgui_impl_sdlsurface2.cpp <BR>
 This supports building with Emscripten.<BR>
 
+[example_sdl2_cpu/](https://github.com/ocornut/imgui/blob/master/examples/example_sdl2_cpu/) <BR>
+SDL2 (Win32, Mac, Linux, etc.) + caller-owned packed-pixel CPU framebuffer renderer example.<BR>
+= main.cpp + imgui_impl_sdl2.cpp + imgui_impl_cpu.cpp <BR>
+This derives the CPU framebuffer format from the current SDL window surface.<BR>
+This supports building with Emscripten.<BR>
+
 [example_sdl2_vulkan/](https://github.com/ocornut/imgui/blob/master/examples/example_sdl2_vulkan/) <BR>
 SDL2 (Win32, Mac, Linux, etc.) + Vulkan example. <BR>
 = main.cpp + imgui_impl_sdl2.cpp + imgui_impl_vulkan.cpp <BR>

examples/example_apple_cpu/Makefile

@@ -0,0 +1,23 @@
+# Makefile for example_apple_cpu, for macOS only
+CXX = clang++
+EXE = example_apple_cpu
+IMGUI_DIR = ../..
+SOURCES = main.mm
+SOURCES += $(IMGUI_DIR)/imgui.cpp $(IMGUI_DIR)/imgui_demo.cpp $(IMGUI_DIR)/imgui_draw.cpp $(IMGUI_DIR)/imgui_tables.cpp $(IMGUI_DIR)/imgui_widgets.cpp
+SOURCES += $(IMGUI_DIR)/backends/imgui_impl_osx.mm $(IMGUI_DIR)/backends/imgui_impl_cpu.cpp
+
+OPTFLAGS ?= -O2
+CXXFLAGS = -std=c++11 -ObjC++ -fobjc-arc -g $(OPTFLAGS) -Wall -Wextra -I$(IMGUI_DIR) -I$(IMGUI_DIR)/backends
+FRAMEWORKS = -framework Cocoa -framework GameController
+
+all: $(EXE)
+	@echo Build complete for Mac OS X
+
+$(EXE): $(SOURCES)
+	$(CXX) $(CXXFLAGS) $(SOURCES) -o $(EXE) $(FRAMEWORKS)
+
+run: all
+	./$(EXE)
+
+clean:
+	rm -f $(EXE) *.o

examples/example_apple_cpu/README.md

@@ -0,0 +1,14 @@
+# How to Build
+
+## macOS
+
+Use the provided `Makefile` or directly:
+```sh
+clang++ -std=c++11 -ObjC++ -fobjc-arc -I ../.. -I ../../backends \
+  main.mm ../../backends/imgui_impl_osx.mm ../../backends/imgui_impl_cpu.cpp ../../imgui*.cpp \
+  -framework Cocoa -framework GameController \
+  -o example_apple_cpu
+```
+
+This example uses Cocoa + `imgui_impl_osx` for windowing/input and `imgui_impl_cpu` for rendering.
+It renders to a native BGRA CPU framebuffer and does not use SDL.

examples/example_apple_cpu/main.mm

@@ -0,0 +1,424 @@
+// Dear ImGui: standalone macOS example using Cocoa + CPU framebuffer rendering.
+
+// Learn about Dear ImGui:
+// - FAQ                  https://dearimgui.com/faq
+// - Getting Started      https://dearimgui.com/getting-started
+// - Documentation        https://dearimgui.com/docs (same as your local docs/ folder).
+// - Introduction, links and more at the top of imgui.cpp
+
+#import <Cocoa/Cocoa.h>
+
+#include "imgui.h"
+#include "imgui_impl_cpu.h"
+#include "imgui_impl_osx.h"
+#include <chrono>
+#include <cmath>
+#include <string.h>
+
+struct ExampleTimingHistory
+{
+    double                      Samples[120];
+    int                         Count;
+    int                         Offset;
+
+    ExampleTimingHistory() : Count(0), Offset(0) { memset(Samples, 0, sizeof(Samples)); }
+
+    void AddSample(double value_ms)
+    {
+        Samples[Offset] = value_ms;
+        Offset = (Offset + 1) % IM_ARRAYSIZE(Samples);
+        if (Count < IM_ARRAYSIZE(Samples))
+            Count++;
+    }
+
+    double GetAverageMs() const
+    {
+        if (Count == 0)
+            return 0.0;
+        double total = 0.0;
+        for (int i = 0; i < Count; i++)
+            total += Samples[i];
+        return total / (double)Count;
+    }
+};
+
+struct ExampleFramebuffer
+{
+    ImVector<unsigned char>      Storage;
+    ImGui_ImplCPU_Framebuffer    CPU;
+    CGColorSpaceRef              ColorSpace;
+    CGDataProviderRef            DataProvider;
+    CGImageRef                   Image;
+
+    ExampleFramebuffer() : ColorSpace(nullptr), DataProvider(nullptr), Image(nullptr)
+    {
+        CPU.Pixels = nullptr;
+        CPU.Width = 0;
+        CPU.Height = 0;
+        CPU.Pitch = 0;
+        CPU.Format = nullptr;
+    }
+};
+
+static double ExampleGetTimeMs()
+{
+    typedef std::chrono::steady_clock Clock;
+    return std::chrono::duration<double, std::milli>(Clock::now().time_since_epoch()).count();
+}
+
+static void DestroyFramebuffer(ExampleFramebuffer* framebuffer)
+{
+    if (framebuffer->Image != nullptr)
+    {
+        CGImageRelease(framebuffer->Image);
+        framebuffer->Image = nullptr;
+    }
+    if (framebuffer->DataProvider != nullptr)
+    {
+        CGDataProviderRelease(framebuffer->DataProvider);
+        framebuffer->DataProvider = nullptr;
+    }
+    if (framebuffer->ColorSpace != nullptr)
+    {
+        CGColorSpaceRelease(framebuffer->ColorSpace);
+        framebuffer->ColorSpace = nullptr;
+    }
+
+    framebuffer->CPU.Pixels = nullptr;
+    framebuffer->CPU.Width = 0;
+    framebuffer->CPU.Height = 0;
+    framebuffer->CPU.Pitch = 0;
+    framebuffer->Storage.clear();
+}
+
+static ImU32 PackBGRA(unsigned char r, unsigned char g, unsigned char b, unsigned char a)
+{
+#if defined(__BYTE_ORDER__) && (__BYTE_ORDER__ == __ORDER_BIG_ENDIAN__)
+    return ((ImU32)b << 24) | ((ImU32)g << 16) | ((ImU32)r << 8) | (ImU32)a;
+#else
+    return (ImU32)b | ((ImU32)g << 8) | ((ImU32)r << 16) | ((ImU32)a << 24);
+#endif
+}
+
+static bool RecreateFramebuffer(ExampleFramebuffer* framebuffer, int width, int height)
+{
+    DestroyFramebuffer(framebuffer);
+
+    framebuffer->Storage.resize(width * height * 4);
+    framebuffer->CPU.Pixels = framebuffer->Storage.Data;
+    framebuffer->CPU.Width = width;
+    framebuffer->CPU.Height = height;
+    framebuffer->CPU.Pitch = width * 4;
+    framebuffer->CPU.Format = ImGui_ImplCPU_GetBuiltinPixelFormat(ImGui_ImplCPU_BuiltinFormat_BGRA8888);
+    if (framebuffer->CPU.Pixels == nullptr)
+        return false;
+
+    framebuffer->ColorSpace = CGColorSpaceCreateDeviceRGB();
+    if (framebuffer->ColorSpace == nullptr)
+    {
+        DestroyFramebuffer(framebuffer);
+        return false;
+    }
+
+    framebuffer->DataProvider = CGDataProviderCreateWithData(nullptr, framebuffer->CPU.Pixels, (size_t)framebuffer->CPU.Pitch * (size_t)framebuffer->CPU.Height, nullptr);
+    if (framebuffer->DataProvider == nullptr)
+    {
+        DestroyFramebuffer(framebuffer);
+        return false;
+    }
+
+    framebuffer->Image = CGImageCreate((size_t)framebuffer->CPU.Width, (size_t)framebuffer->CPU.Height, 8, 32, (size_t)framebuffer->CPU.Pitch, framebuffer->ColorSpace, kCGBitmapByteOrder32Little | kCGImageAlphaNoneSkipFirst, framebuffer->DataProvider, nullptr, false, kCGRenderingIntentDefault);
+    if (framebuffer->Image == nullptr)
+    {
+        DestroyFramebuffer(framebuffer);
+        return false;
+    }
+
+    return true;
+}
+
+static void ClearFramebuffer(ImGui_ImplCPU_Framebuffer* framebuffer, unsigned char r, unsigned char g, unsigned char b, unsigned char a)
+{
+    const ImU32 pixel = PackBGRA(r, g, b, a);
+    for (int y = 0; y < framebuffer->Height; y++)
+    {
+        ImU32* dst = (ImU32*)(void*)(framebuffer->Pixels + (size_t)y * (size_t)framebuffer->Pitch);
+        for (int x = 0; x < framebuffer->Width; x++)
+            dst[x] = pixel;
+    }
+}
+
+//-----------------------------------------------------------------------------------
+// AppView
+//-----------------------------------------------------------------------------------
+
+@interface AppView : NSView
+- (void)shutdownImGui;
+@end
+
+@implementation AppView
+{
+    ExampleFramebuffer  _framebuffer;
+    ExampleTimingHistory _rasterTimes;
+    ExampleTimingHistory _presentTimes;
+    BOOL                _imguiInitialized;
+    BOOL                _frameScheduled;
+}
+
+- (instancetype)initWithFrame:(NSRect)frame
+{
+    self = [super initWithFrame:frame];
+    return self;
+}
+
+- (BOOL)isFlipped
+{
+    return YES;
+}
+
+- (void)viewDidMoveToWindow
+{
+    [super viewDidMoveToWindow];
+    if (self.window != nil && !_imguiInitialized)
+        [self initializeImGui];
+}
+
+- (void)dealloc
+{
+    [self shutdownImGui];
+}
+
+- (void)initializeImGui
+{
+    IMGUI_CHECKVERSION();
+    ImGui::CreateContext();
+    ImGuiIO& io = ImGui::GetIO(); (void)io;
+    io.ConfigFlags |= ImGuiConfigFlags_NavEnableKeyboard;     // Enable Keyboard Controls
+    io.ConfigFlags |= ImGuiConfigFlags_NavEnableGamepad;      // Enable Gamepad Controls
+
+    ImGui::StyleColorsDark();
+
+    ImGui_ImplOSX_Init(self);
+    ImGui_ImplCPU_Init();
+
+    _imguiInitialized = YES;
+    [self scheduleNextFrameAfter:0.0];
+}
+
+- (void)shutdownImGui
+{
+    if (!_imguiInitialized)
+        return;
+
+    DestroyFramebuffer(&_framebuffer);
+    ImGui_ImplCPU_Shutdown();
+    ImGui_ImplOSX_Shutdown();
+    ImGui::DestroyContext();
+    _imguiInitialized = NO;
+}
+
+// Queue the next draw on the main loop instead of pacing to display refresh.
+- (void)scheduleNextFrameAfter:(double)delay_seconds
+{
+    if (_frameScheduled)
+        return;
+    _frameScheduled = YES;
+    dispatch_time_t when = dispatch_time(DISPATCH_TIME_NOW, (int64_t)(delay_seconds * (double)NSEC_PER_SEC));
+    dispatch_after(when, dispatch_get_main_queue(), ^{
+        self->_frameScheduled = NO;
+        [self setNeedsDisplay:YES];
+    });
+}
+
+- (void)renderFrame
+{
+    if (!_imguiInitialized)
+        return;
+
+    if (self.window == nil || [self.window isMiniaturized])
+    {
+        [self scheduleNextFrameAfter:0.01];
+        return;
+    }
+
+    const CGFloat scale = self.window.backingScaleFactor > 0.0 ? self.window.backingScaleFactor : 1.0;
+    const int logical_w = (int)llround(self.bounds.size.width);
+    const int logical_h = (int)llround(self.bounds.size.height);
+    const int framebuffer_w = (int)llround(self.bounds.size.width * scale);
+    const int framebuffer_h = (int)llround(self.bounds.size.height * scale);
+    if (framebuffer_w <= 0 || framebuffer_h <= 0)
+    {
+        [self scheduleNextFrameAfter:0.01];
+        return;
+    }
+
+    if (_framebuffer.CPU.Width != framebuffer_w || _framebuffer.CPU.Height != framebuffer_h)
+        if (!RecreateFramebuffer(&_framebuffer, framebuffer_w, framebuffer_h))
+            return;
+
+    // Start the Dear ImGui frame
+    ImGui_ImplCPU_NewFrame();
+    ImGui_ImplOSX_NewFrame(self);
+    ImGui::NewFrame();
+
+    // Our state
+    static bool show_demo_window = true;
+    static bool show_another_window = false;
+    static ImVec4 clear_color = ImVec4(0.45f, 0.55f, 0.60f, 1.00f);
+
+    // 1. Show the big demo window
+    if (show_demo_window)
+        ImGui::ShowDemoWindow(&show_demo_window);
+
+    // 2. Show a simple window that we create ourselves.
+    {
+        static float f = 0.0f;
+        static int counter = 0;
+        ImGuiIO& io = ImGui::GetIO();
+
+        ImGui::Begin("Hello, world!");
+
+        ImGui::Text("This is some useful text.");
+        ImGui::Checkbox("Demo Window", &show_demo_window);
+        ImGui::Checkbox("Another Window", &show_another_window);
+
+        ImGui::SliderFloat("float", &f, 0.0f, 1.0f);
+        ImGui::ColorEdit3("clear color", (float*)&clear_color);
+
+        if (ImGui::Button("Button"))
+            counter++;
+        ImGui::SameLine();
+        ImGui::Text("counter = %d", counter);
+
+        ImGui::Text("Raster %.3f ms | Present %.3f ms", _rasterTimes.GetAverageMs(), _presentTimes.GetAverageMs());
+        ImGui::Text("Window %d x %d | Framebuffer %d x %d (scale %.2f)", logical_w, logical_h, framebuffer_w, framebuffer_h, scale);
+        ImGui::Text("Application average %.3f ms/frame (%.1f FPS)", 1000.0f / io.Framerate, io.Framerate);
+        ImGui::End();
+    }
+
+    // 3. Show another simple window.
+    if (show_another_window)
+    {
+        ImGui::Begin("Another Window", &show_another_window);
+        ImGui::Text("Hello from another window!");
+        if (ImGui::Button("Close Me"))
+            show_another_window = false;
+        ImGui::End();
+    }
+
+    // Rendering
+    ImGui::Render();
+    const double raster_start_ms = ExampleGetTimeMs();
+    ClearFramebuffer(&_framebuffer.CPU,
+        (unsigned char)(clear_color.x * 255),
+        (unsigned char)(clear_color.y * 255),
+        (unsigned char)(clear_color.z * 255),
+        (unsigned char)(clear_color.w * 255));
+    ImGui_ImplCPU_RenderDrawData(ImGui::GetDrawData(), &_framebuffer.CPU);
+    _rasterTimes.AddSample(ExampleGetTimeMs() - raster_start_ms);
+}
+
+- (void)drawRect:(NSRect)dirtyRect
+{
+    IM_UNUSED(dirtyRect);
+
+    [self renderFrame];
+
+    if (_framebuffer.Image != nullptr)
+    {
+        CGContextRef context = NSGraphicsContext.currentContext.CGContext;
+        // CGImage draws with a bottom-up raster convention here, while the CPU framebuffer is top-down.
+        const double present_start_ms = ExampleGetTimeMs();
+        CGContextSaveGState(context);
+        CGContextTranslateCTM(context, 0.0, self.bounds.size.height);
+        CGContextScaleCTM(context, 1.0, -1.0);
+        CGContextDrawImage(context, CGRectMake(0.0, 0.0, self.bounds.size.width, self.bounds.size.height), _framebuffer.Image);
+        CGContextRestoreGState(context);
+        _presentTimes.AddSample(ExampleGetTimeMs() - present_start_ms);
+    }
+
+    [self scheduleNextFrameAfter:0.0];
+}
+
+@end
+
+//-----------------------------------------------------------------------------------
+// AppDelegate
+//-----------------------------------------------------------------------------------
+
+@interface AppDelegate : NSObject <NSApplicationDelegate>
+@property (nonatomic, readonly) NSWindow* window;
+@property (nonatomic, readonly) AppView* view;
+@end
+
+@implementation AppDelegate
+{
+    NSWindow*   _window;
+    AppView*    _view;
+}
+
+@synthesize window = _window;
+@synthesize view = _view;
+
+- (BOOL)applicationShouldTerminateAfterLastWindowClosed:(NSApplication*)application
+{
+    IM_UNUSED(application);
+    return YES;
+}
+
+- (void)setupMenu
+{
+    NSMenu* main_menu_bar = [[NSMenu alloc] init];
+    NSMenu* app_menu = [[NSMenu alloc] initWithTitle:@"Dear ImGui macOS+CPU Example"];
+    NSMenuItem* menu_item = [app_menu addItemWithTitle:@"Quit Dear ImGui macOS+CPU Example" action:@selector(terminate:) keyEquivalent:@"q"];
+    [menu_item setKeyEquivalentModifierMask:NSEventModifierFlagCommand];
+
+    menu_item = [[NSMenuItem alloc] init];
+    [menu_item setSubmenu:app_menu];
+    [main_menu_bar addItem:menu_item];
+    [NSApp setMainMenu:main_menu_bar];
+}
+
+- (void)applicationDidFinishLaunching:(NSNotification*)notification
+{
+    IM_UNUSED(notification);
+
+    [NSApp setActivationPolicy:NSApplicationActivationPolicyRegular];
+    [self setupMenu];
+
+    NSRect view_rect = NSMakeRect(100.0, 100.0, 1280.0, 720.0);
+    _window = [[NSWindow alloc] initWithContentRect:view_rect styleMask:NSWindowStyleMaskTitled | NSWindowStyleMaskMiniaturizable | NSWindowStyleMaskResizable | NSWindowStyleMaskClosable backing:NSBackingStoreBuffered defer:NO];
+    [_window setTitle:@"Dear ImGui macOS+CPU Example"];
+    [_window setAcceptsMouseMovedEvents:YES];
+    [_window setOpaque:YES];
+
+    _view = [[AppView alloc] initWithFrame:_window.contentView.bounds];
+    [_view setAutoresizingMask:NSViewWidthSizable | NSViewHeightSizable];
+    [_window setContentView:_view];
+    [_window makeKeyAndOrderFront:NSApp];
+    [NSApp activateIgnoringOtherApps:YES];
+}
+
+- (void)applicationWillTerminate:(NSNotification*)notification
+{
+    IM_UNUSED(notification);
+    [_view shutdownImGui];
+}
+
+@end
+
+int main(int argc, char** argv)
+{
+    IM_UNUSED(argc);
+    IM_UNUSED(argv);
+
+    @autoreleasepool
+    {
+        NSApplication* application = [NSApplication sharedApplication];
+        AppDelegate* delegate = [AppDelegate new];
+        [application setDelegate:delegate];
+        [application run];
+    }
+
+    return 0;
+}

examples/example_sdl2_cpu/Makefile

@@ -0,0 +1,73 @@
+#
+# Cross Platform Makefile (example_sdl2_cpu)
+# Compatible with MSYS2/MINGW, Linux and macOS
+#
+# You will need SDL2 (http://www.libsdl.org):
+# Linux:  apt-get install libsdl2-dev
+# macOS:  brew install sdl2
+# MSYS2:  pacman -S mingw-w64-i686-SDL2
+#
+
+EXE = example_sdl2_cpu
+IMGUI_DIR = ../..
+SOURCES = main.cpp
+SOURCES += $(IMGUI_DIR)/imgui.cpp $(IMGUI_DIR)/imgui_demo.cpp $(IMGUI_DIR)/imgui_draw.cpp $(IMGUI_DIR)/imgui_tables.cpp $(IMGUI_DIR)/imgui_widgets.cpp
+SOURCES += $(IMGUI_DIR)/backends/imgui_impl_sdl2.cpp $(IMGUI_DIR)/backends/imgui_impl_cpu.cpp
+OBJS = $(addsuffix .o, $(basename $(notdir $(SOURCES))))
+UNAME_S := $(shell uname -s)
+SDL2_CONFIG ?= $(shell if command -v sdl2-config >/dev/null 2>&1; then command -v sdl2-config; elif [ -x /opt/homebrew/bin/sdl2-config ]; then echo /opt/homebrew/bin/sdl2-config; elif [ -x /usr/local/bin/sdl2-config ]; then echo /usr/local/bin/sdl2-config; else echo sdl2-config; fi)
+
+CXXFLAGS = -std=c++11 -I$(IMGUI_DIR) -I$(IMGUI_DIR)/backends
+OPTFLAGS ?= -O2
+CXXFLAGS += -g $(OPTFLAGS) -Wall -Wformat
+LIBS =
+
+##---------------------------------------------------------------------
+## BUILD FLAGS PER PLATFORM
+##---------------------------------------------------------------------
+
+ifeq ($(UNAME_S), Linux) #LINUX
+	ECHO_MESSAGE = "Linux"
+	LIBS += `$(SDL2_CONFIG) --libs`
+
+	CXXFLAGS += `$(SDL2_CONFIG) --cflags`
+	CFLAGS = $(CXXFLAGS)
+endif
+
+ifeq ($(UNAME_S), Darwin) #APPLE
+	ECHO_MESSAGE = "Mac OS X"
+	LIBS += `$(SDL2_CONFIG) --libs`
+	CXXFLAGS += `$(SDL2_CONFIG) --cflags`
+	CXXFLAGS += -I/usr/local/include -I/opt/local/include
+	CFLAGS = $(CXXFLAGS)
+endif
+
+ifeq ($(OS), Windows_NT)
+	ECHO_MESSAGE = "MinGW"
+	LIBS += -lgdi32 `pkg-config --static --libs sdl2`
+
+	CXXFLAGS += `pkg-config --cflags sdl2`
+	CFLAGS = $(CXXFLAGS)
+endif
+
+##---------------------------------------------------------------------
+## BUILD RULES
+##---------------------------------------------------------------------
+
+%.o:%.cpp
+	$(CXX) $(CXXFLAGS) -c -o $@ $<
+
+%.o:$(IMGUI_DIR)/%.cpp
+	$(CXX) $(CXXFLAGS) -c -o $@ $<
+
+%.o:$(IMGUI_DIR)/backends/%.cpp
+	$(CXX) $(CXXFLAGS) -c -o $@ $<
+
+all: $(EXE)
+	@echo Build complete for $(ECHO_MESSAGE)
+
+$(EXE): $(OBJS)
+	$(CXX) -o $@ $^ $(CXXFLAGS) $(LIBS)
+
+clean:
+	rm -f $(EXE) $(OBJS)

examples/example_sdl2_cpu/Makefile.emscripten

@@ -0,0 +1,54 @@
+CC = emcc
+CXX = em++
+WEB_DIR = web
+EXE = $(WEB_DIR)/index.html
+IMGUI_DIR = ../..
+SOURCES = main.cpp
+SOURCES += $(IMGUI_DIR)/imgui.cpp $(IMGUI_DIR)/imgui_demo.cpp $(IMGUI_DIR)/imgui_draw.cpp $(IMGUI_DIR)/imgui_tables.cpp $(IMGUI_DIR)/imgui_widgets.cpp
+SOURCES += $(IMGUI_DIR)/backends/imgui_impl_sdl2.cpp $(IMGUI_DIR)/backends/imgui_impl_cpu.cpp
+OBJS = $(addprefix em_,$(addsuffix .o, $(basename $(notdir $(SOURCES)))))
+CPPFLAGS =
+LDFLAGS =
+EMS =
+
+EMS += -s USE_SDL=2
+EMS += -s DISABLE_EXCEPTION_CATCHING=1
+LDFLAGS += -s WASM=1 -s ALLOW_MEMORY_GROWTH=1 -s NO_EXIT_RUNTIME=0 -s ASSERTIONS=1
+
+USE_FILE_SYSTEM ?= 0
+ifeq ($(USE_FILE_SYSTEM), 0)
+LDFLAGS += -s NO_FILESYSTEM=1
+CPPFLAGS += -DIMGUI_DISABLE_FILE_FUNCTIONS
+endif
+ifeq ($(USE_FILE_SYSTEM), 1)
+LDFLAGS += --no-heap-copy --preload-file ../../misc/fonts@/fonts
+endif
+
+CPPFLAGS += -I$(IMGUI_DIR) -I$(IMGUI_DIR)/backends
+CPPFLAGS += -Wall -Wformat -O2 $(EMS)
+LDFLAGS += --shell-file ../libs/emscripten/shell_minimal.html
+LDFLAGS += $(EMS)
+
+em_%.o:%.cpp
+	$(CXX) $(CPPFLAGS) $(CXXFLAGS) -c -o $@ $<
+
+em_%.o:$(IMGUI_DIR)/%.cpp
+	$(CXX) $(CPPFLAGS) $(CXXFLAGS) -c -o $@ $<
+
+em_%.o:$(IMGUI_DIR)/backends/%.cpp
+	$(CXX) $(CPPFLAGS) $(CXXFLAGS) -c -o $@ $<
+
+all: $(EXE)
+	@echo Build complete for $(EXE)
+
+$(WEB_DIR):
+	mkdir $@
+
+serve: all
+	python3 -m http.server -d $(WEB_DIR)
+
+$(EXE): $(OBJS) $(WEB_DIR)
+	$(CXX) -o $@ $(OBJS) $(LDFLAGS)
+
+clean:
+	rm -rf $(OBJS) $(WEB_DIR)

examples/example_sdl2_cpu/README.md

@@ -0,0 +1,47 @@
+# How to Build
+
+## Windows with Visual Studio's IDE
+
+Use the provided project file (`example_sdl2_cpu.vcxproj`) or open `imgui_examples.sln`.
+
+## Windows with Visual Studio's CLI
+
+Use `build_win32.bat` or directly:
+```
+set SDL2_DIR=path_to_your_sdl2_folder
+cl /Zi /MD /utf-8 /I.. /I..\.. /I%SDL2_DIR%\include main.cpp ..\..\backends\imgui_impl_sdl2.cpp ..\..\backends\imgui_impl_cpu.cpp ..\..\imgui*.cpp /FeDebug/example_sdl2_cpu.exe /FoDebug/ /link /libpath:%SDL2_DIR%\lib\x86 SDL2.lib SDL2main.lib /subsystem:console
+#                 ^^ include paths                  ^^ source files                                                                                       ^^ output exe                      ^^ output dir   ^^ libraries
+# or for 64-bit:
+cl /Zi /MD /utf-8 /I.. /I..\.. /I%SDL2_DIR%\include main.cpp ..\..\backends\imgui_impl_sdl2.cpp ..\..\backends\imgui_impl_cpu.cpp ..\..\imgui*.cpp /FeDebug/example_sdl2_cpu.exe /FoDebug/ /link /libpath:%SDL2_DIR%\lib\x64 SDL2.lib SDL2main.lib /subsystem:console
+```
+
+## Linux and similar Unixes
+
+Use the provided `Makefile` or directly:
+```
+c++ `sdl2-config --cflags` -I .. -I ../.. -I ../../backends \
+  main.cpp ../../backends/imgui_impl_sdl2.cpp ../../backends/imgui_impl_cpu.cpp ../../imgui*.cpp \
+  `sdl2-config --libs`
+```
+
+## macOS
+
+Use the provided `Makefile` or directly:
+```
+brew install sdl2
+c++ `sdl2-config --cflags` -I .. -I ../.. -I ../../backends \
+  main.cpp ../../backends/imgui_impl_sdl2.cpp ../../backends/imgui_impl_cpu.cpp ../../imgui*.cpp \
+  `sdl2-config --libs`
+```
+
+## Emscripten
+
+Use `Makefile.emscripten`:
+```sh
+source /path/to/emsdk/emsdk_env.sh
+make -f Makefile.emscripten
+```
+
+This makes `web/index.html`, `web/index.js`, and `web/index.wasm`.
+
+This example keeps Dear ImGui on the CPU and allocates its framebuffer in the active SDL window surface format, rather than forcing a fixed RGBA32 output format.

examples/example_sdl2_cpu/build_win32.bat

@@ -0,0 +1,8 @@
+@REM Build for Visual Studio compiler. Run your copy of vcvars32.bat or vcvarsall.bat to setup command-line compiler.
+@set OUT_DIR=Debug
+@set OUT_EXE=example_sdl2_cpu
+@set INCLUDES=/I..\.. /I..\..\backends /I%SDL2_DIR%\include
+@set SOURCES=main.cpp ..\..\backends\imgui_impl_sdl2.cpp ..\..\backends\imgui_impl_cpu.cpp ..\..\imgui*.cpp
+@set LIBS=/LIBPATH:%SDL2_DIR%\lib\x86 SDL2.lib SDL2main.lib
+mkdir %OUT_DIR%
+cl /nologo /Zi /O2 /MD /utf-8 %INCLUDES% %SOURCES% /Fe%OUT_DIR%/%OUT_EXE%.exe /Fo%OUT_DIR%/ /link %LIBS% /subsystem:console

examples/example_sdl2_cpu/example_sdl2_cpu.vcxproj

@@ -0,0 +1,187 @@
+<?xml version="1.0" encoding="utf-8"?>
+<Project DefaultTargets="Build" ToolsVersion="14.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
+  <ItemGroup Label="ProjectConfigurations">
+    <ProjectConfiguration Include="Debug|Win32">
+      <Configuration>Debug</Configuration>
+      <Platform>Win32</Platform>
+    </ProjectConfiguration>
+    <ProjectConfiguration Include="Debug|x64">
+      <Configuration>Debug</Configuration>
+      <Platform>x64</Platform>
+    </ProjectConfiguration>
+    <ProjectConfiguration Include="Release|Win32">
+      <Configuration>Release</Configuration>
+      <Platform>Win32</Platform>
+    </ProjectConfiguration>
+    <ProjectConfiguration Include="Release|x64">
+      <Configuration>Release</Configuration>
+      <Platform>x64</Platform>
+    </ProjectConfiguration>
+  </ItemGroup>
+  <PropertyGroup Label="Globals">
+    <ProjectGuid>{1E9DB182-9BF1-4C7D-8930-85ACAEAC2458}</ProjectGuid>
+    <RootNamespace>example_sdl2_cpu</RootNamespace>
+    <WindowsTargetPlatformVersion>8.1</WindowsTargetPlatformVersion>
+    <ProjectName>example_sdl2_cpu</ProjectName>
+  </PropertyGroup>
+  <Import Project="$(VCTargetsPath)\Microsoft.Cpp.Default.props" />
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'" Label="Configuration">
+    <ConfigurationType>Application</ConfigurationType>
+    <UseDebugLibraries>true</UseDebugLibraries>
+    <CharacterSet>MultiByte</CharacterSet>
+    <PlatformToolset>v140</PlatformToolset>
+  </PropertyGroup>
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug|x64'" Label="Configuration">
+    <ConfigurationType>Application</ConfigurationType>
+    <UseDebugLibraries>true</UseDebugLibraries>
+    <CharacterSet>MultiByte</CharacterSet>
+    <PlatformToolset>v140</PlatformToolset>
+  </PropertyGroup>
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release|Win32'" Label="Configuration">
+    <ConfigurationType>Application</ConfigurationType>
+    <UseDebugLibraries>false</UseDebugLibraries>
+    <WholeProgramOptimization>true</WholeProgramOptimization>
+    <CharacterSet>MultiByte</CharacterSet>
+    <PlatformToolset>v140</PlatformToolset>
+  </PropertyGroup>
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release|x64'" Label="Configuration">
+    <ConfigurationType>Application</ConfigurationType>
+    <UseDebugLibraries>false</UseDebugLibraries>
+    <WholeProgramOptimization>true</WholeProgramOptimization>
+    <CharacterSet>MultiByte</CharacterSet>
+    <PlatformToolset>v140</PlatformToolset>
+  </PropertyGroup>
+  <Import Project="$(VCTargetsPath)\Microsoft.Cpp.props" />
+  <ImportGroup Label="ExtensionSettings">
+  </ImportGroup>
+  <ImportGroup Label="PropertySheets" Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'">
+    <Import Project="$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props" Condition="exists('$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props')" Label="LocalAppDataPlatform" />
+  </ImportGroup>
+  <ImportGroup Condition="'$(Configuration)|$(Platform)'=='Debug|x64'" Label="PropertySheets">
+    <Import Project="$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props" Condition="exists('$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props')" Label="LocalAppDataPlatform" />
+  </ImportGroup>
+  <ImportGroup Label="PropertySheets" Condition="'$(Configuration)|$(Platform)'=='Release|Win32'">
+    <Import Project="$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props" Condition="exists('$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props')" Label="LocalAppDataPlatform" />
+  </ImportGroup>
+  <ImportGroup Condition="'$(Configuration)|$(Platform)'=='Release|x64'" Label="PropertySheets">
+    <Import Project="$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props" Condition="exists('$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props')" Label="LocalAppDataPlatform" />
+  </ImportGroup>
+  <PropertyGroup Label="UserMacros" />
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'">
+    <OutDir>$(ProjectDir)$(Configuration)\</OutDir>
+    <IntDir>$(ProjectDir)$(Configuration)\</IntDir>
+    <IncludePath>$(IncludePath)</IncludePath>
+  </PropertyGroup>
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug|x64'">
+    <OutDir>$(ProjectDir)$(Configuration)\</OutDir>
+    <IntDir>$(ProjectDir)$(Configuration)\</IntDir>
+    <IncludePath>$(IncludePath)</IncludePath>
+  </PropertyGroup>
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release|Win32'">
+    <OutDir>$(ProjectDir)$(Configuration)\</OutDir>
+    <IntDir>$(ProjectDir)$(Configuration)\</IntDir>
+    <IncludePath>$(IncludePath)</IncludePath>
+  </PropertyGroup>
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release|x64'">
+    <OutDir>$(ProjectDir)$(Configuration)\</OutDir>
+    <IntDir>$(ProjectDir)$(Configuration)\</IntDir>
+    <IncludePath>$(IncludePath)</IncludePath>
+  </PropertyGroup>
+  <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'">
+    <ClCompile>
+      <WarningLevel>Level4</WarningLevel>
+      <Optimization>Disabled</Optimization>
+      <AdditionalIncludeDirectories>..\..;..\..\backends;%SDL2_DIR%\include;%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
+      <AdditionalOptions>/utf-8 %(AdditionalOptions)</AdditionalOptions>
+    </ClCompile>
+    <Link>
+      <GenerateDebugInformation>true</GenerateDebugInformation>
+      <AdditionalLibraryDirectories>%SDL2_DIR%\lib\x86;%(AdditionalLibraryDirectories)</AdditionalLibraryDirectories>
+      <AdditionalDependencies>SDL2.lib;SDL2main.lib;%(AdditionalDependencies)</AdditionalDependencies>
+      <SubSystem>Console</SubSystem>
+      <IgnoreSpecificDefaultLibraries>msvcrt.lib</IgnoreSpecificDefaultLibraries>
+    </Link>
+  </ItemDefinitionGroup>
+  <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Debug|x64'">
+    <ClCompile>
+      <WarningLevel>Level4</WarningLevel>
+      <Optimization>Disabled</Optimization>
+      <AdditionalIncludeDirectories>..\..;..\..\backends;%SDL2_DIR%\include;%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
+      <AdditionalOptions>/utf-8 %(AdditionalOptions)</AdditionalOptions>
+    </ClCompile>
+    <Link>
+      <GenerateDebugInformation>true</GenerateDebugInformation>
+      <AdditionalLibraryDirectories>%SDL2_DIR%\lib\x64;%(AdditionalLibraryDirectories)</AdditionalLibraryDirectories>
+      <AdditionalDependencies>SDL2.lib;SDL2main.lib;%(AdditionalDependencies)</AdditionalDependencies>
+      <SubSystem>Console</SubSystem>
+      <IgnoreSpecificDefaultLibraries>msvcrt.lib</IgnoreSpecificDefaultLibraries>
+    </Link>
+  </ItemDefinitionGroup>
+  <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Release|Win32'">
+    <ClCompile>
+      <WarningLevel>Level4</WarningLevel>
+      <Optimization>MaxSpeed</Optimization>
+      <FunctionLevelLinking>true</FunctionLevelLinking>
+      <IntrinsicFunctions>true</IntrinsicFunctions>
+      <AdditionalIncludeDirectories>..\..;..\..\backends;%SDL2_DIR%\include;%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
+      <BufferSecurityCheck>false</BufferSecurityCheck>
+      <AdditionalOptions>/utf-8 %(AdditionalOptions)</AdditionalOptions>
+    </ClCompile>
+    <Link>
+      <GenerateDebugInformation>true</GenerateDebugInformation>
+      <EnableCOMDATFolding>true</EnableCOMDATFolding>
+      <OptimizeReferences>true</OptimizeReferences>
+      <AdditionalLibraryDirectories>%SDL2_DIR%\lib\x86;%(AdditionalLibraryDirectories)</AdditionalLibraryDirectories>
+      <AdditionalDependencies>SDL2.lib;SDL2main.lib;%(AdditionalDependencies)</AdditionalDependencies>
+      <SubSystem>Console</SubSystem>
+      <IgnoreSpecificDefaultLibraries>
+      </IgnoreSpecificDefaultLibraries>
+    </Link>
+  </ItemDefinitionGroup>
+  <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Release|x64'">
+    <ClCompile>
+      <WarningLevel>Level4</WarningLevel>
+      <Optimization>MaxSpeed</Optimization>
+      <FunctionLevelLinking>true</FunctionLevelLinking>
+      <IntrinsicFunctions>true</IntrinsicFunctions>
+      <AdditionalIncludeDirectories>..\..;..\..\backends;%SDL2_DIR%\include;%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
+      <BufferSecurityCheck>false</BufferSecurityCheck>
+      <AdditionalOptions>/utf-8 %(AdditionalOptions)</AdditionalOptions>
+    </ClCompile>
+    <Link>
+      <GenerateDebugInformation>true</GenerateDebugInformation>
+      <EnableCOMDATFolding>true</EnableCOMDATFolding>
+      <OptimizeReferences>true</OptimizeReferences>
+      <AdditionalLibraryDirectories>%SDL2_DIR%\lib\x64;%(AdditionalLibraryDirectories)</AdditionalLibraryDirectories>
+      <AdditionalDependencies>SDL2.lib;SDL2main.lib;%(AdditionalDependencies)</AdditionalDependencies>
+      <SubSystem>Console</SubSystem>
+      <IgnoreSpecificDefaultLibraries>
+      </IgnoreSpecificDefaultLibraries>
+    </Link>
+  </ItemDefinitionGroup>
+  <ItemGroup>
+    <ClCompile Include="..\..\imgui.cpp" />
+    <ClCompile Include="..\..\imgui_demo.cpp" />
+    <ClCompile Include="..\..\imgui_draw.cpp" />
+    <ClCompile Include="..\..\imgui_tables.cpp" />
+    <ClCompile Include="..\..\imgui_widgets.cpp" />
+    <ClCompile Include="..\..\backends\imgui_impl_sdl2.cpp" />
+    <ClCompile Include="..\..\backends\imgui_impl_cpu.cpp" />
+    <ClCompile Include="main.cpp" />
+  </ItemGroup>
+  <ItemGroup>
+    <ClInclude Include="..\..\imconfig.h" />
+    <ClInclude Include="..\..\imgui.h" />
+    <ClInclude Include="..\..\imgui_internal.h" />
+    <ClInclude Include="..\..\backends\imgui_impl_sdl2.h" />
+    <ClInclude Include="..\..\backends\imgui_impl_cpu.h" />
+  </ItemGroup>
+  <ItemGroup>
+    <None Include="..\..\misc\debuggers\imgui.natstepfilter" />
+    <None Include="..\..\misc\debuggers\imgui.natvis" />
+    <None Include="..\README.txt" />
+  </ItemGroup>
+  <Import Project="$(VCTargetsPath)\Microsoft.Cpp.targets" />
+  <ImportGroup Label="ExtensionTargets">
+  </ImportGroup>
+</Project>

examples/example_sdl2_cpu/example_sdl2_cpu.vcxproj.filters

@@ -0,0 +1,64 @@
+<?xml version="1.0" encoding="utf-8"?>
+<Project ToolsVersion="4.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
+  <ItemGroup>
+    <Filter Include="imgui">
+      <UniqueIdentifier>{20b90ce4-7fcb-4731-b9a0-075f875de82d}</UniqueIdentifier>
+    </Filter>
+    <Filter Include="sources">
+      <UniqueIdentifier>{f18ab499-84e1-499f-8eff-9754361e0e52}</UniqueIdentifier>
+      <Extensions>cpp;c;cc;cxx;def;odl;idl;hpj;bat;asm;asmx</Extensions>
+    </Filter>
+  </ItemGroup>
+  <ItemGroup>
+    <ClCompile Include="..\..\imgui.cpp">
+      <Filter>imgui</Filter>
+    </ClCompile>
+    <ClCompile Include="..\..\imgui_demo.cpp">
+      <Filter>imgui</Filter>
+    </ClCompile>
+    <ClCompile Include="..\..\imgui_draw.cpp">
+      <Filter>imgui</Filter>
+    </ClCompile>
+    <ClCompile Include="main.cpp">
+      <Filter>sources</Filter>
+    </ClCompile>
+    <ClCompile Include="..\..\imgui_tables.cpp">
+      <Filter>imgui</Filter>
+    </ClCompile>
+    <ClCompile Include="..\..\imgui_widgets.cpp">
+      <Filter>imgui</Filter>
+    </ClCompile>
+    <ClCompile Include="..\..\backends\imgui_impl_sdl2.cpp">
+      <Filter>sources</Filter>
+    </ClCompile>
+    <ClCompile Include="..\..\backends\imgui_impl_cpu.cpp">
+      <Filter>sources</Filter>
+    </ClCompile>
+  </ItemGroup>
+  <ItemGroup>
+    <ClInclude Include="..\..\imconfig.h">
+      <Filter>imgui</Filter>
+    </ClInclude>
+    <ClInclude Include="..\..\imgui.h">
+      <Filter>imgui</Filter>
+    </ClInclude>
+    <ClInclude Include="..\..\imgui_internal.h">
+      <Filter>imgui</Filter>
+    </ClInclude>
+    <ClInclude Include="..\..\backends\imgui_impl_cpu.h">
+      <Filter>sources</Filter>
+    </ClInclude>
+    <ClInclude Include="..\..\backends\imgui_impl_sdl2.h">
+      <Filter>sources</Filter>
+    </ClInclude>
+  </ItemGroup>
+  <ItemGroup>
+    <None Include="..\README.txt" />
+    <None Include="..\..\misc\debuggers\imgui.natvis">
+      <Filter>imgui</Filter>
+    </None>
+    <None Include="..\..\misc\debuggers\imgui.natstepfilter">
+      <Filter>imgui</Filter>
+    </None>
+  </ItemGroup>
+</Project>

examples/example_sdl2_cpu/main.cpp

@@ -0,0 +1,321 @@
+// main.cpp
+// Example program using imgui_impl_cpu backend
+
+#include "imgui.h"
+#include "imgui_impl_cpu.h"
+#include "imgui_impl_sdl2.h"
+#include <SDL.h>
+#include <chrono>
+#include <stdio.h>
+#include <string.h>
+#ifdef __EMSCRIPTEN__
+#include "../libs/emscripten/emscripten_mainloop_stub.h"
+#endif
+
+struct ExampleTimingHistory
+{
+    double                      Samples[120];
+    int                         Count;
+    int                         Offset;
+
+    ExampleTimingHistory() : Count(0), Offset(0) { memset(Samples, 0, sizeof(Samples)); }
+
+    void AddSample(double value_ms)
+    {
+        Samples[Offset] = value_ms;
+        Offset = (Offset + 1) % IM_ARRAYSIZE(Samples);
+        if (Count < IM_ARRAYSIZE(Samples))
+            Count++;
+    }
+
+    double GetAverageMs() const
+    {
+        if (Count == 0)
+            return 0.0;
+        double total = 0.0;
+        for (int i = 0; i < Count; i++)
+            total += Samples[i];
+        return total / (double)Count;
+    }
+};
+
+struct ExampleFramebuffer
+{
+    ImVector<unsigned char>      Storage;
+    ImVector<ImU32>              Palette;
+    ImGui_ImplCPU_PixelFormat    Format;
+    ImGui_ImplCPU_Framebuffer    CPU;
+    SDL_Surface*                 Surface;
+    Uint32                       SDLFormat;
+
+    ExampleFramebuffer() { memset((void*)this, 0, sizeof(*this)); }
+};
+
+static double ExampleGetTimeMs()
+{
+    typedef std::chrono::steady_clock Clock;
+    return std::chrono::duration<double, std::milli>(Clock::now().time_since_epoch()).count();
+}
+
+static void InitCPUFormatFromSDL(ImGui_ImplCPU_PixelFormat* out, ImVector<ImU32>* out_palette, const SDL_PixelFormat* format)
+{
+    memset(out, 0, sizeof(*out));
+    out->BitsPerPixel = format->BitsPerPixel;
+    out->BytesPerPixel = format->BytesPerPixel;
+    out->Rmask = format->Rmask;
+    out->Gmask = format->Gmask;
+    out->Bmask = format->Bmask;
+    out->Amask = format->Amask;
+    out->Rshift = (ImU8)format->Rshift;
+    out->Gshift = (ImU8)format->Gshift;
+    out->Bshift = (ImU8)format->Bshift;
+    out->Ashift = (ImU8)format->Ashift;
+    out->Rloss = (ImU8)format->Rloss;
+    out->Gloss = (ImU8)format->Gloss;
+    out->Bloss = (ImU8)format->Bloss;
+    out->Aloss = (ImU8)format->Aloss;
+    out->Palette = nullptr;
+    out->PaletteSize = 0;
+    out->MapColorFn = nullptr;
+
+    out_palette->clear();
+    if (format->palette != nullptr && format->palette->colors != nullptr && format->palette->ncolors > 0)
+    {
+        out_palette->resize(format->palette->ncolors);
+        for (int i = 0; i < format->palette->ncolors; i++)
+        {
+            const SDL_Color& c = format->palette->colors[i];
+            (*out_palette)[i] = IM_COL32(c.r, c.g, c.b, c.a);
+        }
+        out->Palette = out_palette->Data;
+        out->PaletteSize = out_palette->Size;
+    }
+}
+
+static bool RecreateFramebuffer(ExampleFramebuffer* framebuffer, SDL_Surface* window_surface)
+{
+    if (framebuffer->Surface != nullptr)
+    {
+        SDL_FreeSurface(framebuffer->Surface);
+        framebuffer->Surface = nullptr;
+    }
+
+    const int width = window_surface->w;
+    const int height = window_surface->h;
+    const int bytes_per_pixel = window_surface->format->BytesPerPixel;
+    if (width <= 0 || height <= 0 || bytes_per_pixel <= 0)
+        return false;
+
+    InitCPUFormatFromSDL(&framebuffer->Format, &framebuffer->Palette, window_surface->format);
+    framebuffer->Storage.resize(width * height * bytes_per_pixel);
+    framebuffer->CPU.Pixels = framebuffer->Storage.Data;
+    framebuffer->CPU.Width = width;
+    framebuffer->CPU.Height = height;
+    framebuffer->CPU.Pitch = width * bytes_per_pixel;
+    framebuffer->CPU.Format = &framebuffer->Format;
+    framebuffer->SDLFormat = window_surface->format->format;
+    framebuffer->Surface = SDL_CreateRGBSurfaceWithFormatFrom(framebuffer->CPU.Pixels, width, height, window_surface->format->BitsPerPixel, framebuffer->CPU.Pitch, window_surface->format->format);
+    return framebuffer->Surface != nullptr;
+}
+
+int main(int, char**)
+{
+    // Setup SDL
+    if (SDL_Init(SDL_INIT_VIDEO | SDL_INIT_TIMER | SDL_INIT_GAMECONTROLLER) != 0)
+    {
+        printf("Error: %s\n", SDL_GetError());
+        return -1;
+    }
+
+    // From 2.0.18: Enable native IME.
+#ifdef SDL_HINT_IME_SHOW_UI
+    SDL_SetHint(SDL_HINT_IME_SHOW_UI, "1");
+#endif
+
+    // Create window
+    float main_scale = ImGui_ImplSDL2_GetContentScaleForDisplay(0);
+    SDL_WindowFlags window_flags = (SDL_WindowFlags)(SDL_WINDOW_RESIZABLE | SDL_WINDOW_ALLOW_HIGHDPI | SDL_WINDOW_SHOWN);
+    SDL_Window* window = SDL_CreateWindow("Dear ImGui SDL2+CPU Example",
+        SDL_WINDOWPOS_CENTERED, SDL_WINDOWPOS_CENTERED,
+        (int)(1280 * main_scale), (int)(720 * main_scale), window_flags);
+    if (!window)
+    {
+        printf("Error creating window: %s\n", SDL_GetError());
+        return -1;
+    }
+
+    SDL_Surface* window_surface = SDL_GetWindowSurface(window);
+    if (!window_surface)
+    {
+        printf("Error getting window surface: %s\n", SDL_GetError());
+        return -1;
+    }
+
+    int win_w = window_surface->w;
+    int win_h = window_surface->h;
+    ExampleFramebuffer framebuffer;
+    if (!RecreateFramebuffer(&framebuffer, window_surface))
+    {
+        printf("Error creating framebuffer: %s\n", SDL_GetError());
+        return -1;
+    }
+
+    // Setup Dear ImGui context
+    IMGUI_CHECKVERSION();
+    ImGui::CreateContext();
+    ImGuiIO& io = ImGui::GetIO(); (void)io;
+    io.ConfigFlags |= ImGuiConfigFlags_NavEnableKeyboard;     // Enable Keyboard Controls
+    io.ConfigFlags |= ImGuiConfigFlags_NavEnableGamepad;      // Enable Gamepad Controls
+#ifdef __EMSCRIPTEN__
+    io.IniFilename = nullptr;
+#endif
+
+    // Setup Dear ImGui style
+    ImGui::StyleColorsDark();
+
+    // Setup scaling
+    ImGuiStyle& style = ImGui::GetStyle();
+    style.ScaleAllSizes(main_scale);        // Bake a fixed style scale.
+    style.FontScaleDpi = main_scale;
+
+    // Setup Platform/Renderer backends
+    ImGui_ImplSDL2_InitForOther(window);
+    ImGui_ImplSDL2_SetGamepadMode(ImGui_ImplSDL2_GamepadMode_AutoFirst, nullptr, 0);
+    ImGui_ImplCPU_Init();
+
+    // Our state
+    bool show_demo_window = true;
+    bool show_another_window = false;
+    ImVec4 clear_color = ImVec4(0.45f, 0.55f, 0.60f, 1.00f);
+    ExampleTimingHistory raster_times;
+    ExampleTimingHistory present_times;
+
+    // Main loop
+    bool done = false;
+#ifdef __EMSCRIPTEN__
+    EMSCRIPTEN_MAINLOOP_BEGIN
+#else
+    while (!done)
+#endif
+    {
+        // Poll and handle events (inputs, window resize, etc.)
+        SDL_Event event;
+        while (SDL_PollEvent(&event))
+        {
+            ImGui_ImplSDL2_ProcessEvent(&event);
+            if (event.type == SDL_QUIT)
+                done = true;
+
+            if (event.type == SDL_WINDOWEVENT)
+            {
+                if (event.window.event == SDL_WINDOWEVENT_CLOSE && event.window.windowID == SDL_GetWindowID(window))
+                    done = true;
+
+                if (event.window.event == SDL_WINDOWEVENT_SIZE_CHANGED || event.window.event == SDL_WINDOWEVENT_RESIZED)
+                {
+                    // Recreate framebuffer at new size
+                    window_surface = SDL_GetWindowSurface(window);
+                    int new_w = window_surface->w;
+                    int new_h = window_surface->h;
+                    if (new_w != win_w || new_h != win_h || window_surface->format->format != framebuffer.SDLFormat)
+                    {
+                        if (!RecreateFramebuffer(&framebuffer, window_surface))
+                        {
+                            printf("Error creating framebuffer after resize: %s\n", SDL_GetError());
+                            return -1;
+                        }
+                        win_w = new_w;
+                        win_h = new_h;
+                    }
+                }
+            }
+        }
+
+        // Skip rendering when minimized to avoid busy-looping
+        if (SDL_GetWindowFlags(window) & SDL_WINDOW_MINIMIZED)
+        {
+            SDL_Delay(10);
+            continue;
+        }
+
+        // Start the Dear ImGui frame
+        ImGui_ImplCPU_NewFrame();
+        ImGui_ImplSDL2_NewFrame();
+        ImGui::NewFrame();
+
+        int logical_w = 0;
+        int logical_h = 0;
+        SDL_GetWindowSize(window, &logical_w, &logical_h);
+
+        // 1. Show the big demo window
+        if (show_demo_window)
+            ImGui::ShowDemoWindow(&show_demo_window);
+
+        // 2. Show a simple window that we create ourselves. Mirror the SDL_Renderer example.
+        {
+            static float f = 0.0f;
+            static int counter = 0;
+
+            ImGui::Begin("Hello, world!");                          // Create a window called "Hello, world!" and append into it.
+
+            ImGui::Text("This is some useful text.");               // Display some text
+            ImGui::Checkbox("Demo Window", &show_demo_window);      // Edit bools storing our window open/close state
+            ImGui::Checkbox("Another Window", &show_another_window);
+
+            ImGui::SliderFloat("float", &f, 0.0f, 1.0f);            // Edit 1 float using a slider from 0.0f to 1.0f
+            ImGui::ColorEdit3("clear color", (float*)&clear_color); // Edit 3 floats representing a color
+
+            if (ImGui::Button("Button"))                            // Buttons return true when clicked
+                counter++;
+            ImGui::SameLine();
+            ImGui::Text("counter = %d", counter);
+
+            ImGui::Text("Raster %.3f ms | Present %.3f ms", raster_times.GetAverageMs(), present_times.GetAverageMs());
+            ImGui::Text("Window %d x %d | Framebuffer %d x %d", logical_w, logical_h, framebuffer.CPU.Width, framebuffer.CPU.Height);
+            ImGui::Text("Application average %.3f ms/frame (%.1f FPS)", 1000.0f / io.Framerate, io.Framerate);
+            ImGui::End();
+        }
+
+        // 3. Show another simple window.
+        if (show_another_window)
+        {
+            ImGui::Begin("Another Window", &show_another_window);   // Pass a pointer to our bool variable (the window will have a closing button that will clear the bool when clicked)
+            ImGui::Text("Hello from another window!");
+            if (ImGui::Button("Close Me"))
+                show_another_window = false;
+            ImGui::End();
+        }
+
+        // Rendering
+        ImGui::Render();
+
+        const double raster_start_ms = ExampleGetTimeMs();
+        SDL_FillRect(framebuffer.Surface, nullptr, SDL_MapRGBA(framebuffer.Surface->format,
+            (Uint8)(clear_color.x * 255),
+            (Uint8)(clear_color.y * 255),
+            (Uint8)(clear_color.z * 255),
+            (Uint8)(clear_color.w * 255)));
+
+        ImGui_ImplCPU_RenderDrawData(ImGui::GetDrawData(), &framebuffer.CPU);
+        raster_times.AddSample(ExampleGetTimeMs() - raster_start_ms);
+
+        const double present_start_ms = ExampleGetTimeMs();
+        SDL_BlitSurface(framebuffer.Surface, nullptr, window_surface, nullptr);
+        SDL_UpdateWindowSurface(window);
+        present_times.AddSample(ExampleGetTimeMs() - present_start_ms);
+    }
+#ifdef __EMSCRIPTEN__
+    EMSCRIPTEN_MAINLOOP_END;
+#endif
+
+    ImGui_ImplCPU_Shutdown();
+    ImGui_ImplSDL2_Shutdown();
+    ImGui::DestroyContext();
+
+    if (framebuffer.Surface != nullptr)
+        SDL_FreeSurface(framebuffer.Surface);
+    SDL_DestroyWindow(window);
+    SDL_Quit();
+
+    return 0;
+}

examples/example_sdl2_surface/main.cpp

@@ -5,11 +5,46 @@
 #include "imgui_impl_sdl2.h"
 #include "imgui_impl_sdlsurface2.h"
 #include <SDL.h>
+#include <chrono>
 #include <stdio.h>
+#include <string.h>
 #ifdef __EMSCRIPTEN__
 #include "../libs/emscripten/emscripten_mainloop_stub.h"
 #endif
 
+struct ExampleTimingHistory
+{
+    double                      Samples[120];
+    int                         Count;
+    int                         Offset;
+
+    ExampleTimingHistory() : Count(0), Offset(0) { memset(Samples, 0, sizeof(Samples)); }
+
+    void AddSample(double value_ms)
+    {
+        Samples[Offset] = value_ms;
+        Offset = (Offset + 1) % IM_ARRAYSIZE(Samples);
+        if (Count < IM_ARRAYSIZE(Samples))
+            Count++;
+    }
+
+    double GetAverageMs() const
+    {
+        if (Count == 0)
+            return 0.0;
+        double total = 0.0;
+        for (int i = 0; i < Count; i++)
+            total += Samples[i];
+        return total / (double)Count;
+    }
+};
+
+static double ExampleGetTimeMs()
+{
+    typedef std::chrono::steady_clock Clock;
+    return std::chrono::duration<double, std::milli>(Clock::now().time_since_epoch()).count();
+}
+
 int main(int, char**)
 {
     // Setup SDL
@@ -79,6 +114,8 @@ int main(int, char**)
     bool show_demo_window = true;
     bool show_another_window = false;
     ImVec4 clear_color = ImVec4(0.45f, 0.55f, 0.60f, 1.00f);
+    ExampleTimingHistory raster_times;
+    ExampleTimingHistory present_times;
 
     // Main loop
     bool done = false;
@@ -133,6 +170,10 @@ int main(int, char**)
         ImGui_ImplSDL2_NewFrame();
         ImGui::NewFrame();
 
+        int logical_w = 0;
+        int logical_h = 0;
+        SDL_GetWindowSize(window, &logical_w, &logical_h);
+
         // 1. Show the big demo window
         if (show_demo_window)
             ImGui::ShowDemoWindow(&show_demo_window);
@@ -156,6 +197,8 @@ int main(int, char**)
             ImGui::SameLine();
             ImGui::Text("counter = %d", counter);
 
+            ImGui::Text("Raster %.3f ms | Present %.3f ms", raster_times.GetAverageMs(), present_times.GetAverageMs());
+            ImGui::Text("Window %d x %d | Framebuffer %d x %d", logical_w, logical_h, framebuffer->w, framebuffer->h);
             ImGui::Text("Application average %.3f ms/frame (%.1f FPS)", 1000.0f / io.Framerate, io.Framerate);
             ImGui::End();
         }
@@ -173,6 +216,7 @@ int main(int, char**)
         // Rendering
         ImGui::Render();
 
+        const double raster_start_ms = ExampleGetTimeMs();
         SDL_FillRect(framebuffer, nullptr, SDL_MapRGBA(framebuffer->format,
             (Uint8)(clear_color.x * 255),
             (Uint8)(clear_color.y * 255),
@@ -180,9 +224,12 @@ int main(int, char**)
             (Uint8)(clear_color.w * 255)));
 
         ImGui_ImplSDLSurface2_RenderDrawData(ImGui::GetDrawData());
+        raster_times.AddSample(ExampleGetTimeMs() - raster_start_ms);
 
+        const double present_start_ms = ExampleGetTimeMs();
         SDL_BlitSurface(framebuffer, nullptr, window_surface, nullptr);
         SDL_UpdateWindowSurface(window);
+        present_times.AddSample(ExampleGetTimeMs() - present_start_ms);
     }
 #ifdef __EMSCRIPTEN__
     EMSCRIPTEN_MAINLOOP_END;

examples/imgui_examples.sln

@@ -31,6 +31,8 @@ Project("{8BC9CEB8-8B4A-11D0-8D11-00A0C91BC942}") = "example_sdl2_sdlrenderer2",
 EndProject
 Project("{8BC9CEB8-8B4A-11D0-8D11-00A0C91BC942}") = "example_sdl2_surface", "example_sdl2_surface\example_sdl2_surface.vcxproj", "{47525E56-7D05-474E-A455-64C5BBFFC029}"
 EndProject
+Project("{8BC9CEB8-8B4A-11D0-8D11-00A0C91BC942}") = "example_sdl2_cpu", "example_sdl2_cpu\example_sdl2_cpu.vcxproj", "{1E9DB182-9BF1-4C7D-8930-85ACAEAC2458}"
+EndProject
 Project("{8BC9CEB8-8B4A-11D0-8D11-00A0C91BC942}") = "example_sdl3_opengl3", "example_sdl3_opengl3\example_sdl3_opengl3.vcxproj", "{84AAA301-84FE-428B-9E3E-817BC8123C0C}"
 EndProject
 Project("{8BC9CEB8-8B4A-11D0-8D11-00A0C91BC942}") = "example_sdl3_sdlrenderer3", "example_sdl3_sdlrenderer3\example_sdl3_sdlrenderer3.vcxproj", "{C0290D21-3AD2-4A35-ABBC-A2F5F48326DA}"
@@ -167,6 +169,14 @@ Global
 		{47525E56-7D05-474E-A455-64C5BBFFC029}.Release|Win32.Build.0 = Release|Win32
 		{47525E56-7D05-474E-A455-64C5BBFFC029}.Release|x64.ActiveCfg = Release|x64
 		{47525E56-7D05-474E-A455-64C5BBFFC029}.Release|x64.Build.0 = Release|x64
+		{1E9DB182-9BF1-4C7D-8930-85ACAEAC2458}.Debug|Win32.ActiveCfg = Debug|Win32
+		{1E9DB182-9BF1-4C7D-8930-85ACAEAC2458}.Debug|Win32.Build.0 = Debug|Win32
+		{1E9DB182-9BF1-4C7D-8930-85ACAEAC2458}.Debug|x64.ActiveCfg = Debug|x64
+		{1E9DB182-9BF1-4C7D-8930-85ACAEAC2458}.Debug|x64.Build.0 = Debug|x64
+		{1E9DB182-9BF1-4C7D-8930-85ACAEAC2458}.Release|Win32.ActiveCfg = Release|Win32
+		{1E9DB182-9BF1-4C7D-8930-85ACAEAC2458}.Release|Win32.Build.0 = Release|Win32
+		{1E9DB182-9BF1-4C7D-8930-85ACAEAC2458}.Release|x64.ActiveCfg = Release|x64
+		{1E9DB182-9BF1-4C7D-8930-85ACAEAC2458}.Release|x64.Build.0 = Release|x64
 		{84AAA301-84FE-428B-9E3E-817BC8123C0C}.Debug|Win32.ActiveCfg = Debug|Win32
 		{84AAA301-84FE-428B-9E3E-817BC8123C0C}.Debug|Win32.Build.0 = Debug|Win32
 		{84AAA301-84FE-428B-9E3E-817BC8123C0C}.Debug|x64.ActiveCfg = Debug|x64

misc/README.txt

@@ -2,6 +2,7 @@
 misc/cpp/
   InputText() wrappers for C++ standard library (STL) type: std::string.
   This is also an example of how you may wrap your own similar types.
+  Includes imgui_cpu_validate.cpp, an offscreen validation utility for the imgui_impl_cpu backend.
 
 misc/debuggers/
   Helper files for popular debuggers (Visual Studio, GDB, LLDB).

misc/cpp/imgui_cpu_validate.cpp

@@ -0,0 +1,385 @@
+// dear imgui: imgui_impl_cpu format validation utility
+// Build manually with imgui core sources + backends/imgui_impl_cpu.cpp.
+
+#include "imgui.h"
+#include "imgui_impl_cpu.h"
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+struct ValidationBuffer
+{
+    ImVector<unsigned char>      Storage;
+    ImVector<ImU32>              Palette;
+    ImGui_ImplCPU_PixelFormat    Format;
+    ImGui_ImplCPU_Framebuffer    Framebuffer;
+
+    ValidationBuffer() { memset((void*)this, 0, sizeof(*this)); }
+};
+
+static inline unsigned char Validation_ExpandBits(ImU32 value, int bits)
+{
+    if (bits <= 0)
+        return 0;
+    if (bits >= 8)
+        return (unsigned char)value;
+    ImU32 max_value = (1u << bits) - 1u;
+    return (unsigned char)((value * 255u + (max_value >> 1)) / max_value);
+}
+
+static inline ImU32 Validation_CompressBits(unsigned char value, int bits)
+{
+    if (bits <= 0)
+        return 0;
+    if (bits >= 8)
+        return value;
+    ImU32 max_value = (1u << bits) - 1u;
+    return (ImU32)((value * max_value + 127u) / 255u);
+}
+
+static inline void Validation_UnpackCanonicalRGBA(ImU32 pixel, unsigned char* r, unsigned char* g, unsigned char* b, unsigned char* a)
+{
+    *r = (unsigned char)((pixel >> IM_COL32_R_SHIFT) & 0xFF);
+    *g = (unsigned char)((pixel >> IM_COL32_G_SHIFT) & 0xFF);
+    *b = (unsigned char)((pixel >> IM_COL32_B_SHIFT) & 0xFF);
+    *a = (unsigned char)((pixel >> IM_COL32_A_SHIFT) & 0xFF);
+}
+
+static inline ImU32 Validation_ReadRawPixel(const ValidationBuffer& buffer, int x, int y)
+{
+    const unsigned char* p = buffer.Framebuffer.Pixels + (size_t)y * (size_t)buffer.Framebuffer.Pitch + (size_t)x * (size_t)buffer.Format.BytesPerPixel;
+    switch (buffer.Format.BytesPerPixel)
+    {
+    case 1:
+        return *p;
+    case 2:
+    {
+        ImU16 pixel = 0;
+        memcpy(&pixel, p, sizeof(pixel));
+        return pixel;
+    }
+    case 3:
+#if defined(__BYTE_ORDER__) && (__BYTE_ORDER__ == __ORDER_BIG_ENDIAN__)
+        return (ImU32)((p[0] << 16) | (p[1] << 8) | p[2]);
+#else
+        return (ImU32)(p[0] | (p[1] << 8) | (p[2] << 16));
+#endif
+    case 4:
+    {
+        ImU32 pixel = 0;
+        memcpy(&pixel, p, sizeof(pixel));
+        return pixel;
+    }
+    default:
+        return 0;
+    }
+}
+
+static inline void Validation_WriteRawPixel(ValidationBuffer* buffer, int x, int y, ImU32 pixel)
+{
+    unsigned char* p = buffer->Framebuffer.Pixels + (size_t)y * (size_t)buffer->Framebuffer.Pitch + (size_t)x * (size_t)buffer->Format.BytesPerPixel;
+    switch (buffer->Format.BytesPerPixel)
+    {
+    case 1:
+        *p = (unsigned char)pixel;
+        return;
+    case 2:
+    {
+        ImU16 v = (ImU16)pixel;
+        memcpy(p, &v, sizeof(v));
+        return;
+    }
+    case 3:
+#if defined(__BYTE_ORDER__) && (__BYTE_ORDER__ == __ORDER_BIG_ENDIAN__)
+        p[0] = (unsigned char)((pixel >> 16) & 0xFF);
+        p[1] = (unsigned char)((pixel >> 8) & 0xFF);
+        p[2] = (unsigned char)(pixel & 0xFF);
+#else
+        p[0] = (unsigned char)(pixel & 0xFF);
+        p[1] = (unsigned char)((pixel >> 8) & 0xFF);
+        p[2] = (unsigned char)((pixel >> 16) & 0xFF);
+#endif
+        return;
+    case 4:
+        memcpy(p, &pixel, sizeof(pixel));
+        return;
+    default:
+        return;
+    }
+}
+
+static ImU32 Validation_MapNearestPaletteColor(const ImGui_ImplCPU_PixelFormat* format, unsigned char r, unsigned char g, unsigned char b, unsigned char a)
+{
+    unsigned int best_distance = 0xFFFFFFFFu;
+    int best_index = 0;
+    for (int i = 0; i < format->PaletteSize; i++)
+    {
+        unsigned char pr, pg, pb, pa;
+        Validation_UnpackCanonicalRGBA(format->Palette[i], &pr, &pg, &pb, &pa);
+        int dr = (int)pr - (int)r;
+        int dg = (int)pg - (int)g;
+        int db = (int)pb - (int)b;
+        int da = (int)pa - (int)a;
+        unsigned int distance = (unsigned int)(dr * dr + dg * dg + db * db + da * da);
+        if (distance < best_distance)
+        {
+            best_distance = distance;
+            best_index = i;
+            if (distance == 0)
+                break;
+        }
+    }
+    return (ImU32)best_index;
+}
+
+static ImU32 Validation_PackPixel(const ValidationBuffer& buffer, unsigned char r, unsigned char g, unsigned char b, unsigned char a)
+{
+    if (buffer.Format.Palette != nullptr && buffer.Format.PaletteSize > 0)
+    {
+        if (buffer.Format.MapColorFn != nullptr)
+            return buffer.Format.MapColorFn(&buffer.Format, r, g, b, a);
+        return Validation_MapNearestPaletteColor(&buffer.Format, r, g, b, a);
+    }
+
+    ImU32 pixel = 0;
+    if (buffer.Format.Rmask != 0)
+        pixel |= (Validation_CompressBits(r, 8 - buffer.Format.Rloss) << buffer.Format.Rshift) & buffer.Format.Rmask;
+    if (buffer.Format.Gmask != 0)
+        pixel |= (Validation_CompressBits(g, 8 - buffer.Format.Gloss) << buffer.Format.Gshift) & buffer.Format.Gmask;
+    if (buffer.Format.Bmask != 0)
+        pixel |= (Validation_CompressBits(b, 8 - buffer.Format.Bloss) << buffer.Format.Bshift) & buffer.Format.Bmask;
+    if (buffer.Format.Amask != 0)
+        pixel |= (Validation_CompressBits(a, 8 - buffer.Format.Aloss) << buffer.Format.Ashift) & buffer.Format.Amask;
+    return pixel;
+}
+
+static void Validation_DecodePixel(const ValidationBuffer& buffer, int x, int y, unsigned char* r, unsigned char* g, unsigned char* b, unsigned char* a)
+{
+    ImU32 pixel = Validation_ReadRawPixel(buffer, x, y);
+    if (buffer.Format.Palette != nullptr && buffer.Format.PaletteSize > 0)
+    {
+        if (pixel >= (ImU32)buffer.Format.PaletteSize)
+        {
+            *r = *g = *b = *a = 0;
+            return;
+        }
+        Validation_UnpackCanonicalRGBA(buffer.Format.Palette[pixel], r, g, b, a);
+        return;
+    }
+
+    *r = (buffer.Format.Rmask != 0) ? Validation_ExpandBits((pixel & buffer.Format.Rmask) >> buffer.Format.Rshift, 8 - buffer.Format.Rloss) : 0;
+    *g = (buffer.Format.Gmask != 0) ? Validation_ExpandBits((pixel & buffer.Format.Gmask) >> buffer.Format.Gshift, 8 - buffer.Format.Gloss) : 0;
+    *b = (buffer.Format.Bmask != 0) ? Validation_ExpandBits((pixel & buffer.Format.Bmask) >> buffer.Format.Bshift, 8 - buffer.Format.Bloss) : 0;
+    *a = (buffer.Format.Amask != 0) ? Validation_ExpandBits((pixel & buffer.Format.Amask) >> buffer.Format.Ashift, 8 - buffer.Format.Aloss) : 255;
+}
+
+static bool Validation_InitBuffer(ValidationBuffer* buffer, int width, int height, const ImGui_ImplCPU_PixelFormat* format)
+{
+    buffer->Format = *format;
+    buffer->Framebuffer.Width = width;
+    buffer->Framebuffer.Height = height;
+    buffer->Framebuffer.Pitch = width * buffer->Format.BytesPerPixel;
+    buffer->Storage.resize(height * buffer->Framebuffer.Pitch);
+    buffer->Framebuffer.Pixels = buffer->Storage.Data;
+    buffer->Framebuffer.Format = &buffer->Format;
+    return buffer->Framebuffer.Pixels != nullptr;
+}
+
+static bool Validation_InitIndexedBuffer(ValidationBuffer* buffer, int width, int height)
+{
+    buffer->Palette.clear();
+    buffer->Palette.push_back(IM_COL32(114, 140, 153, 255));
+    buffer->Palette.push_back(IM_COL32(255, 0, 0, 255));
+    buffer->Palette.push_back(IM_COL32(0, 255, 0, 255));
+    buffer->Palette.push_back(IM_COL32(0, 0, 255, 255));
+    buffer->Palette.push_back(IM_COL32(255, 255, 255, 255));
+    buffer->Palette.push_back(IM_COL32(255, 255, 0, 255));
+
+    memset(&buffer->Format, 0, sizeof(buffer->Format));
+    buffer->Format.BitsPerPixel = 8;
+    buffer->Format.BytesPerPixel = 1;
+    buffer->Format.Palette = buffer->Palette.Data;
+    buffer->Format.PaletteSize = buffer->Palette.Size;
+    buffer->Format.MapColorFn = Validation_MapNearestPaletteColor;
+    return Validation_InitBuffer(buffer, width, height, &buffer->Format);
+}
+
+static void Validation_ClearBuffer(ValidationBuffer* buffer, unsigned char r, unsigned char g, unsigned char b, unsigned char a)
+{
+    ImU32 pixel = Validation_PackPixel(*buffer, r, g, b, a);
+    for (int y = 0; y < buffer->Framebuffer.Height; y++)
+        for (int x = 0; x < buffer->Framebuffer.Width; x++)
+            Validation_WriteRawPixel(buffer, x, y, pixel);
+}
+
+static bool Validation_CompareBuffers(const char* name, const ValidationBuffer& reference, const ValidationBuffer& candidate, int tolerance_rgb, int tolerance_alpha, bool ignore_alpha)
+{
+    for (int y = 0; y < reference.Framebuffer.Height; y++)
+        for (int x = 0; x < reference.Framebuffer.Width; x++)
+        {
+            unsigned char rr, rg, rb, ra;
+            unsigned char cr, cg, cb, ca;
+            Validation_DecodePixel(reference, x, y, &rr, &rg, &rb, &ra);
+            Validation_DecodePixel(candidate, x, y, &cr, &cg, &cb, &ca);
+
+            if (abs((int)rr - (int)cr) > tolerance_rgb
+                || abs((int)rg - (int)cg) > tolerance_rgb
+                || abs((int)rb - (int)cb) > tolerance_rgb
+                || (!ignore_alpha && abs((int)ra - (int)ca) > tolerance_alpha))
+            {
+                printf("Validation failed for %s at (%d, %d): ref=(%u,%u,%u,%u) got=(%u,%u,%u,%u)\n",
+                    name, x, y, rr, rg, rb, ra, cr, cg, cb, ca);
+                return false;
+            }
+        }
+    return true;
+}
+
+static void Validation_FillBGRAImage(ImVector<unsigned char>* storage, ImGui_ImplCPU_Texture* texture)
+{
+    const int width = 48;
+    const int height = 32;
+    storage->resize(width * height * 4);
+    for (int y = 0; y < height; y++)
+        for (int x = 0; x < width; x++)
+        {
+            unsigned char r = (unsigned char)(32 + x * 4);
+            unsigned char g = (unsigned char)(32 + y * 6);
+            unsigned char b = (unsigned char)(255 - x * 4);
+            int offset = (y * width + x) * 4;
+            (*storage)[offset + 0] = b;
+            (*storage)[offset + 1] = g;
+            (*storage)[offset + 2] = r;
+            (*storage)[offset + 3] = 255;
+        }
+
+    texture->Pixels = storage->Data;
+    texture->Width = width;
+    texture->Height = height;
+    texture->Pitch = width * 4;
+    texture->Format = ImGui_ImplCPU_GetBuiltinPixelFormat(ImGui_ImplCPU_BuiltinFormat_BGRA8888);
+}
+
+static void Validation_BuildMainScene(const ImGui_ImplCPU_Texture* image_texture)
+{
+    ImDrawList* bg = ImGui::GetBackgroundDrawList();
+    bg->AddRectFilled(ImVec2(8.0f, 8.0f), ImVec2(40.0f, 40.0f), IM_COL32(255, 0, 0, 255));
+    bg->AddRectFilled(ImVec2(472.0f, 280.0f), ImVec2(504.0f, 312.0f), IM_COL32(0, 255, 0, 255));
+
+    ImGui::SetNextWindowPos(ImVec2(32.0f, 24.0f), ImGuiCond_Always);
+    ImGui::SetNextWindowSize(ImVec2(320.0f, 180.0f), ImGuiCond_Always);
+    ImGui::Begin("Validation", nullptr, ImGuiWindowFlags_NoResize | ImGuiWindowFlags_NoCollapse);
+    ImGui::Text("CPU format validation");
+    ImGui::Text("Top-left marker is red. Bottom-right is green.");
+    ImGui::ColorButton("##color", ImVec4(0.2f, 0.6f, 0.9f, 1.0f), 0, ImVec2(48.0f, 24.0f));
+    ImGui::SameLine();
+    ImGui::Image((ImTextureID)(intptr_t)image_texture, ImVec2((float)image_texture->Width, (float)image_texture->Height));
+    ImGui::ProgressBar(0.65f, ImVec2(240.0f, 0.0f));
+    ImGui::End();
+}
+
+static void Validation_BuildPaletteScene()
+{
+    ImDrawList* bg = ImGui::GetBackgroundDrawList();
+    bg->AddRectFilled(ImVec2(8.0f, 8.0f), ImVec2(40.0f, 40.0f), IM_COL32(255, 0, 0, 255));
+    bg->AddRectFilled(ImVec2(472.0f, 280.0f), ImVec2(504.0f, 312.0f), IM_COL32(0, 255, 0, 255));
+    bg->AddRectFilled(ImVec2(160.0f, 32.0f), ImVec2(320.0f, 96.0f), IM_COL32(0, 0, 255, 255));
+    bg->AddRectFilled(ImVec2(56.0f, 232.0f), ImVec2(168.0f, 280.0f), IM_COL32(255, 255, 0, 255));
+    bg->AddRectFilled(ImVec2(360.0f, 64.0f), ImVec2(456.0f, 112.0f), IM_COL32(255, 255, 255, 255));
+}
+
+static bool Validation_RenderInto(ValidationBuffer* buffer, ImDrawData* draw_data)
+{
+    Validation_ClearBuffer(buffer, 114, 140, 153, 255);
+    ImGui_ImplCPU_RenderDrawData(draw_data, &buffer->Framebuffer);
+    return true;
+}
+
+int main(int, char**)
+{
+    IMGUI_CHECKVERSION();
+    ImGui::CreateContext();
+    ImGuiIO& io = ImGui::GetIO();
+    io.DisplaySize = ImVec2(512.0f, 320.0f);
+    io.DeltaTime = 1.0f / 60.0f;
+    io.Fonts->TexDesiredFormat = ImTextureFormat_Alpha8;
+
+    ImGui::StyleColorsDark();
+    ImGui_ImplCPU_Init();
+
+    ImVector<unsigned char> image_storage;
+    ImGui_ImplCPU_Texture image_texture;
+    memset(&image_texture, 0, sizeof(image_texture));
+    Validation_FillBGRAImage(&image_storage, &image_texture);
+
+    ValidationBuffer reference;
+    Validation_InitBuffer(&reference, 512, 320, ImGui_ImplCPU_GetBuiltinPixelFormat(ImGui_ImplCPU_BuiltinFormat_RGBA8888));
+
+    const ImGui_ImplCPU_BuiltinFormat builtin_formats[] =
+    {
+        ImGui_ImplCPU_BuiltinFormat_RGBA8888,
+        ImGui_ImplCPU_BuiltinFormat_BGRA8888,
+        ImGui_ImplCPU_BuiltinFormat_ARGB8888,
+        ImGui_ImplCPU_BuiltinFormat_ABGR8888,
+        ImGui_ImplCPU_BuiltinFormat_RGB565,
+        ImGui_ImplCPU_BuiltinFormat_ARGB1555,
+        ImGui_ImplCPU_BuiltinFormat_RGBA4444,
+        ImGui_ImplCPU_BuiltinFormat_RGB888,
+        ImGui_ImplCPU_BuiltinFormat_BGR888
+    };
+    const char* builtin_names[] =
+    {
+        "RGBA8888",
+        "BGRA8888",
+        "ARGB8888",
+        "ABGR8888",
+        "RGB565",
+        "ARGB1555",
+        "RGBA4444",
+        "RGB888",
+        "BGR888"
+    };
+    const int builtin_tolerance[] =
+    {
+        0, 0, 0, 0, 8, 8, 17, 0, 0
+    };
+    const bool builtin_ignore_alpha[] =
+    {
+        false, false, false, false, true, false, false, true, true
+    };
+
+    ImGui_ImplCPU_NewFrame();
+    ImGui::NewFrame();
+    Validation_BuildMainScene(&image_texture);
+    ImGui::Render();
+    if (!Validation_RenderInto(&reference, ImGui::GetDrawData()))
+        return 1;
+
+    for (int i = 0; i < IM_ARRAYSIZE(builtin_formats); i++)
+    {
+        ValidationBuffer candidate;
+        Validation_InitBuffer(&candidate, 512, 320, ImGui_ImplCPU_GetBuiltinPixelFormat(builtin_formats[i]));
+        Validation_RenderInto(&candidate, ImGui::GetDrawData());
+        if (!Validation_CompareBuffers(builtin_names[i], reference, candidate, builtin_tolerance[i], builtin_tolerance[i], builtin_ignore_alpha[i]))
+            return 1;
+    }
+
+    ValidationBuffer palette_reference;
+    Validation_InitBuffer(&palette_reference, 512, 320, ImGui_ImplCPU_GetBuiltinPixelFormat(ImGui_ImplCPU_BuiltinFormat_RGBA8888));
+    ValidationBuffer palette_candidate;
+    Validation_InitIndexedBuffer(&palette_candidate, 512, 320);
+
+    ImGui_ImplCPU_NewFrame();
+    ImGui::NewFrame();
+    Validation_BuildPaletteScene();
+    ImGui::Render();
+    Validation_RenderInto(&palette_reference, ImGui::GetDrawData());
+    Validation_RenderInto(&palette_candidate, ImGui::GetDrawData());
+    if (!Validation_CompareBuffers("Indexed8", palette_reference, palette_candidate, 0, 0, false))
+        return 1;
+
+    ImGui_ImplCPU_Shutdown();
+    ImGui::DestroyContext();
+    printf("imgui_impl_cpu validation passed.\n");
+    return 0;
+}