> ## Documentation Index
> Fetch the complete documentation index at: https://mintlify.com/ocornut/imgui/llms.txt
> Use this file to discover all available pages before exploring further.

# Demo & Debug Windows

> Built-in demonstration and debugging windows for Dear ImGui

Dear ImGui provides several built-in windows for demonstration, debugging, and learning. These are invaluable tools for both learning the library and diagnosing issues in your application.

## ShowDemoWindow

Displays the comprehensive Dear ImGui demo window showcasing all features.

```cpp theme={null}
void ShowDemoWindow(bool* p_open = NULL);
```

### Parameters

<ParamField path="p_open" type="bool*" default="NULL">
  Optional pointer to a boolean controlling window visibility. When the user clicks the close button, this is set to false.
</ParamField>

### Description

The demo window is the best way to learn Dear ImGui. It demonstrates:

* All widget types and their variants
* Layout and grouping techniques
* Window management features
* Input handling examples
* Tables, trees, and list boxes
* Drag & drop functionality
* Multi-selection patterns
* Custom drawing with ImDrawList
* Performance optimization tips

### Example

```cpp theme={null}
// Simple usage - always show
ImGui::ShowDemoWindow();

// With close button
bool show_demo = true;
while (running) {
    ImGui::NewFrame();
    
    if (show_demo) {
        ImGui::ShowDemoWindow(&show_demo);
    }
    
    ImGui::Render();
}
```

### With Menu Integration

```cpp theme={null}
bool show_demo = false;

if (ImGui::BeginMainMenuBar()) {
    if (ImGui::BeginMenu("Windows")) {
        ImGui::MenuItem("Demo Window", NULL, &show_demo);
        ImGui::EndMenu();
    }
    ImGui::EndMainMenuBar();
}

if (show_demo) {
    ImGui::ShowDemoWindow(&show_demo);
}
```

<Note>
  The demo window source code (imgui\_demo.cpp) is extensively commented and serves as a learning resource. Read through it to understand best practices.
</Note>

## ShowMetricsWindow

Displays the metrics/debugger window showing Dear ImGui internals.

```cpp theme={null}
void ShowMetricsWindow(bool* p_open = NULL);
```

### Parameters

<ParamField path="p_open" type="bool*" default="NULL">
  Optional pointer to a boolean controlling window visibility.
</ParamField>

### Description

The metrics window provides deep insight into Dear ImGui's internal state:

* Active windows and their properties
* Draw command statistics
* Vertex and index buffer usage
* Memory allocations
* Active ID and hover information
* Font atlas details
* Input state monitoring
* Settings inspection

### Example

```cpp theme={null}
bool show_metrics = false;

// Toggle with keyboard shortcut
if (ImGui::IsKeyPressed(ImGuiKey_F1)) {
    show_metrics = !show_metrics;
}

if (show_metrics) {
    ImGui::ShowMetricsWindow(&show_metrics);
}
```

### Debugging Window Issues

```cpp theme={null}
// When debugging window behavior
ImGui::Begin("My Window");
ImGui::Text("Some content");
ImGui::End();

// Show metrics to inspect window state
ImGui::ShowMetricsWindow();
// Navigate to Windows -> "My Window" to see:
// - Position, Size
// - Flags
// - Draw commands
// - Active/Focused state
```

<Note>
  Use the metrics window to diagnose performance issues. It shows draw call counts and vertex/index buffer sizes, helping identify rendering bottlenecks.
</Note>

## ShowDebugLogWindow

Displays a simplified log of important Dear ImGui events.

```cpp theme={null}
void ShowDebugLogWindow(bool* p_open = NULL);
```

### Parameters

<ParamField path="p_open" type="bool*" default="NULL">
  Optional pointer to a boolean controlling window visibility.
</ParamField>

### Description

The debug log window records:

* Navigation events
* Focus changes
* Input capture events
* Window creation/destruction
* Table operations
* Multi-select operations
* Other significant state changes

### Example

```cpp theme={null}
bool show_log = false;

if (ImGui::BeginMainMenuBar()) {
    if (ImGui::BeginMenu("Debug")) {
        ImGui::MenuItem("Debug Log", NULL, &show_log);
        ImGui::EndMenu();
    }
    ImGui::EndMainMenuBar();
}

if (show_log) {
    ImGui::ShowDebugLogWindow(&show_log);
}
```

### Debugging Input Issues

```cpp theme={null}
// Enable log when debugging input handling
static bool show_log = true;
ImGui::ShowDebugLogWindow(&show_log);

// Your UI code
if (ImGui::Button("Test Button")) {
    // Check debug log to see:
    // - Whether button received focus
    // - Navigation events
    // - Input routing
}
```

<Note>
  The debug log is particularly useful when debugging keyboard navigation and focus issues.
</Note>

## ShowAboutWindow

Displays the About window with version, credits, and build information.

```cpp theme={null}
void ShowAboutWindow(bool* p_open = NULL);
```

### Parameters

<ParamField path="p_open" type="bool*" default="NULL">
  Optional pointer to a boolean controlling window visibility.
</ParamField>

### Description

The About window displays:

* Dear ImGui version (e.g., "1.92.7 WIP")
* Credits and contributors
* Build/system information
* Compiler details
* Configuration flags
* Links to documentation and resources

### Example

```cpp theme={null}
bool show_about = false;

if (ImGui::BeginMainMenuBar()) {
    if (ImGui::BeginMenu("Help")) {
        if (ImGui::MenuItem("About Dear ImGui")) {
            show_about = true;
        }
        ImGui::EndMenu();
    }
    ImGui::EndMainMenuBar();
}

if (show_about) {
    ImGui::ShowAboutWindow(&show_about);
}
```

### Version Information

```cpp theme={null}
// Get version programmatically
const char* version = ImGui::GetVersion();
printf("Using Dear ImGui %s\n", version);

// Show in about window
ImGui::ShowAboutWindow();
```

## Complete Debug UI Example

```cpp theme={null}
struct DebugWindows {
    bool show_demo = false;
    bool show_metrics = false;
    bool show_log = false;
    bool show_about = false;
};

static DebugWindows debug;

void RenderDebugMenu() {
    if (ImGui::BeginMainMenuBar()) {
        if (ImGui::BeginMenu("Windows")) {
            ImGui::MenuItem("Demo Window", "F1", &debug.show_demo);
            ImGui::Separator();
            ImGui::MenuItem("Metrics/Debugger", "F2", &debug.show_metrics);
            ImGui::MenuItem("Debug Log", "F3", &debug.show_log);
            ImGui::Separator();
            ImGui::MenuItem("About Dear ImGui", NULL, &debug.show_about);
            ImGui::EndMenu();
        }
        ImGui::EndMainMenuBar();
    }
    
    // Keyboard shortcuts
    if (ImGui::IsKeyPressed(ImGuiKey_F1)) debug.show_demo = !debug.show_demo;
    if (ImGui::IsKeyPressed(ImGuiKey_F2)) debug.show_metrics = !debug.show_metrics;
    if (ImGui::IsKeyPressed(ImGuiKey_F3)) debug.show_log = !debug.show_log;
    
    // Render windows
    if (debug.show_demo) ImGui::ShowDemoWindow(&debug.show_demo);
    if (debug.show_metrics) ImGui::ShowMetricsWindow(&debug.show_metrics);
    if (debug.show_log) ImGui::ShowDebugLogWindow(&debug.show_log);
    if (debug.show_about) ImGui::ShowAboutWindow(&debug.show_about);
}
```

<Warning>
  Keep debug windows disabled in release builds to avoid exposing internal state to end users. Use preprocessor directives:

  ```cpp theme={null}
  #ifdef _DEBUG
      ImGui::ShowMetricsWindow();
  #endif
  ```
</Warning>

## Best Practices

### Learning the Library

```cpp theme={null}
// Always make the demo available during development
#ifdef _DEBUG
    static bool show_demo = true;
    ImGui::ShowDemoWindow(&show_demo);
#endif
```

### Performance Monitoring

```cpp theme={null}
// Monitor draw calls and vertex counts
static bool show_metrics = false;
if (ImGui::IsKeyPressed(ImGuiKey_F11)) {
    show_metrics = !show_metrics;
}

if (show_metrics) {
    ImGui::ShowMetricsWindow(&show_metrics);
    // Check "Drawlists" section for performance stats
}
```

### Issue Reporting

```cpp theme={null}
// When reporting bugs, include metrics window info
ImGui::ShowMetricsWindow();
// Take a screenshot showing:
// - Window hierarchy
// - Draw command counts
// - Active/Hovered items
// Include in your bug report
```