> For the complete documentation index, see [llms.txt](https://vgui-framework.gitbook.io/docs/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://vgui-framework.gitbook.io/docs/readme.md).

# Introduction

C++17 immediate-mode UI with a DirectX 11 renderer and a theme inspired by CS 1.6. The library has no ImGui dependency and uses no Valve source code.

## Guides

1. [Getting started](/docs/getting-started.md): builds, DLL linking, Win32 and the frame loop.
2. [API reference](/docs/api.md): widgets, parameters and return values.
3. [Examples](/docs/examples.md): tabs, IDs, layout and themes.
4. [Architecture](/docs/architecture.md): rendering, input and widget implementation.
5. [FAQ](/docs/faq.md): common mistakes and current limits.
6. [External rendering](/docs/external-rendering.md): host devices, render targets, images and recovery.

## Quick example

Keep widget values in your application and submit the UI each frame:

```cpp
// Keep these between frames.
vgui::Rect window{20, 20, 400, 260};
bool sound = true;
float volume = 0.65f;

// Inside the application loop.
if (ui.begin_frame()) {
    ui.begin_window("test", window);
    ui.checkbox("Sound", sound);
    ui.slider("Volume", volume, 0.0f, 1.0f);
    if (ui.button("Reset")) volume = 0.65f;
    ui.end_window();
    ui.end_frame();
}
```

[demo/main.cpp](https://github.com/insomfaze/vgui-framework/blob/main/demo/main.cpp) is a complete desktop application. [examples/settings.cpp](https://github.com/insomfaze/vgui-framework/blob/main/examples/settings.cpp) shows a small settings menu that is also compiled and exercised by the tests.

## Basic rules

* Use one `Context` per HWND, on the window's UI thread.
* Forward WndProc messages to `window_message()` and return its result when handled.
* If `begin_frame()` returns false, skip UI submission and `end_frame()`.
* Balance all begin/end and push/pop calls.
* Widget data belongs to the caller. References to that data are not kept between frames.
* Keep labels stable. `test##audio` displays `test` but uses the full label as its ID.
* Coordinates are logical pixels at 96 DPI; automatic scaling follows the window DPI.
* Text is UTF-8. Enable per-monitor DPI awareness before creating windows.
* Buttons return true on activation; value controls return true when their value changes.

The API is still evolving. See [vgui.hpp](https://github.com/insomfaze/vgui-framework/blob/main/include/vgui.hpp) for public declarations; headers in `src/` are private. Planned widgets are listed in [TODO.md](https://github.com/insomfaze/vgui-framework/blob/main/TODO.md).


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