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Immediate-Mode-UI/Nuklear · source
Snapshot 0 · 2026-11-04T12:47:26Z · C ·
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13d6a75d442ba6b91acdae8296838b0a964c33742baf94251bfff6fdd51aae7fGitHub description at capture
A single-header ANSI C immediate mode cross-platform GUI library
README at capture
# Nuklear
[](https://github.com/Immediate-Mode-UI/Nuklear/actions)
This is a minimal-state, immediate-mode graphical user interface toolkit
written in ANSI C and licensed under public domain. It was designed as a simple
embeddable user interface for application and does not have any dependencies,
a default render backend or OS window/input handling but instead provides a
highly modular, library-based approach, with simple input state for input and
draw commands describing primitive shapes as output. So instead of providing a
layered library that tries to abstract over a number of platform and
render backends, it focuses only on the actual UI.
## Features
- Immediate-mode graphical user interface toolkit
- Single-header library
- Written in C89 (ANSI C)
- Small codebase (~18kLOC)
- Focus on portability, efficiency and simplicity
- No dependencies (not even the standard library if not wanted)
- Fully skinnable and customizable
- Low memory footprint with total control of memory usage if needed / wanted
- UTF-8 support
- No global or hidden state
- Customizable library modules (you can compile and use only what you need)
- Optional font baker and vertex buffer output
- [Documentation](https://Immediate-Mode-UI.github.io/Nuklear/)
## Usage
This library is self-contained in one single header file and can be used either
in header-only mode or in implementation mode. The header-only mode is used
by default when included and allows including this header in other headers
and does not contain the actual implementation.
The implementation mode requires defining the preprocessor macro
`NK_IMPLEMENTATION` in *one* .c/.cpp file before `#include`ing this file, e.g.:
```c
#define NK_IMPLEMENTATION
#include "nuklear.h"
```
IMPORTANT: Every time you include "nuklear.h" you have to define the same optional flags.
This is very important; not doing it either leads to compiler errors, or even worse, stack corruptions.
## Gallery
## Example
The example below shows the general structure of a Nuklear application:
one-time setup, then once per frame mirror the input, build the user
interface and draw it. Nuklear does no rendering itself, so the parts
marked `your_...` are provided by your rendering backend:
```c
/* init gui state (once at startup) */
struct nk_user_font font;
struct nk_context ctx;
font.userdata = nk_handle_ptr(your_font_data);
font.height = your_font_height;
font.width = your_text_width_calculation;
nk_init_fixed(&ctx, calloc(1, MAX_MEMORY), MAX_MEMORY, &font);
while (running) {
/* mirror your window's input state into nuklear */
nk_input_begin(&ctx);
/* nk_input_motion(&ctx, ...), nk_input_button(&ctx, ...),
* nk_input_key(&ctx, ...), ... */
nk_input_end(&ctx);
/* build the user interface */
{
enum {EASY, HARD};
static int op = EASY;
static float value = 0.6f;
if (nk_begin(&ctx, "Show", nk_rect(50, 50, 220, 220),
NK_WINDOW_BORDER|NK_WINDOW_MOVABLE|NK_WINDOW_CLOSABLE)) {
/* fixed widget pixel width */
nk_layout_row_static(&ctx, 30, 80, 1);
if (nk_button_label(&ctx, "button")) {
/* event handling */
}
/* fixed widget window ratio width */
nk_layout_row_dynamic(&ctx, 30, 2);
if (nk_option_label(&ctx, "easy", op == EASY)) op = EASY;
if (nk_option_label(&ctx, "hard", op == HARD)) op = HARD;
/* custom widget pixel width */
nk_layout_row_begin(&ctx, NK_STATIC, 30, 2);
{
nk_layout_row_push(&ctx, 50);
nk_label(&ctx, "Volume:", NK_TEXT_LEFT);
nk_layout_row_push(&ctx, 110);
nk_slider_float(&ctx, 0, &value, 1.0f, 0.1f);
}
nk_layout_row_end(&ctx);
}
nk_end(&ctx);
}
/* draw: hand this frame's draw commands to your renderer */
{
const struct nk_command *cmd;
nk_foreach(cmd, &ctx) {
switch (cmd->type) {
case NK_COMMAND_LINE:
your_draw_line_function((const struct nk_command_line*)cmd);
break;
case NK_COMMAND_RECT:
your_draw_rect_function((const struct nk_command_rect*)cmd);
break;
default:
/* [...] */
break;
}
}
nk_clear(&ctx);
}
}
```
Ready-to-use rendering backends for GLFW, SDL, X11, GDI, Direct3D, Vulkan
and more are in the [demo](demo/) folder, each with its own build
instructions, e.g.:
```sh
make -C demo/glfw_opengl3
```
More complete programs can be found in the [example](example/) folder.
Rendered by one of the backends, the interface built above looks like this:
## Bindings
There are a number of nuklear bindings for different languages created by other authors.
I cannot attest for their quality since I am not necessarily proficient in any of these
languages. Furthermore there are no guarantee that all bindings will always be kept up to date:
- [Java](https://github.com/glegris/nuklear4j) by Guillaume Legris
- [D](https://github.com/Timu5/bindbc-nuklear) by Mateusz Muszyński
- [Golang](https://github.com/golang-ui/nuklear) by golang-ui@github.com
- [Rust](https://github.com/snuk182/nuklear-rust) by snuk182@github.com
- [Chicken](https://github.com/wasamasa/nuklear) by wasamasa@github.com
- [Nim](https://github.com/zacharycarter/nuklear-nim) by zacharycarter@github.com
- Lua
- [LÖVE-Nuklear](https://github.com/keharriso/love-nuklear) by Kevin Harrison
- [MoonNuklear](https://github.com/stetre/moonnuklear) by Stefano Trettel
- Python
- [pyNuklear](https://github.com/billsix/pyNuklear) by William Emerison Six (ctypes-based wrapper)
- [pynk](https://github.com/nathanrw/nuklear-cffi) by nathanrw@github.com (cffi binding)
- [CSharp/.NET](https://github.com/cartman300/NuklearDotNet) by cartman300@github.com
- [V](https://github.com/nsauzede/vnk) by Nicolas Sauzede
## Credits
Developed by Micha Mettke and every direct or indirect contributor to the GitHub.
Embeds `stb_texedit`, `stb_truetype` and `stb_rectpack` by Sean Barrett (public domain)
Embeds `ProggyClean.ttf` font by Tristan Grimmer (MIT license).
Big thank you to Omar Cornut (ocornut@github) for his [imgui](https://github.com/ocornut/imgui) library and
giving me the inspiration for this library, Casey Muratori for handmade hero
and his original immediate-mode graphical user interface idea and Sean
Barrett for his amazing single-header [libraries](https://github.com/nothings/stb) which restored my faith
in libraries and brought me to create some of my own. Finally Apoorva Joshi for his single-header [file packer](http://apoorvaj.io/single-header-packer.html).
## License
Nuklear is avaliable under either the MIT License or public domain.
See [LICENSE](LICENSE) for more info.