Nuklear

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 renderbackend or OS window and input handling but instead provides a very modular library approach by using 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 only focuses on the actual UI.

Features

Immediate mode graphical user interface toolkit
Single header library
Written in C89 (ANSI C)
Small codebase (~15kLOC)
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 memory control if needed or 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

Building

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 to define the preprocessor macro NK_IMPLEMENTATION in one .c/.cpp file before #includeing this file, e.g.:

    #define NK_IMPLEMENTATION
    #include "nuklear.h"

Gallery

Example

/* init gui state */
struct nk_context ctx;
nk_init_fixed(&ctx, calloc(1, MAX_MEMORY), MAX_MEMORY, &font);

enum {EASY, HARD};
int op = EASY;
float value = 0.6f;
int i =  20;

struct nk_panel layout;
nk_begin(&ctx, &layout, "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_text(&ctx, "button", NK_BUTTON_DEFAULT)) {
        /* event handling */
    }

    /* fixed widget window ratio width */
    nk_layout_row_dynamic(&ctx, 30, 2);
    if (nk_option(&ctx, "easy", op == EASY)) op = EASY;
    if (nk_option(&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);

CREDITS:

Developed by Micha Mettke and every direct or indirect contributor to the GitHub.

Embeds stb_texedit, stb_truetype and stb_rectpack by Sean Barret (public domain) Embeds ProggyClean.ttf font by Tristan Grimmer (MIT license).

Big thank you to Omar Cornut (ocornut@github) for his 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 Barret for his amazing single header libraries which restored my faith in libraries and brought me to create some of my own.

LICENSE:

This software is dual-licensed to the public domain and under the following license: you are granted a perpetual, irrevocable license to copy, modify, publish and distribute this file as you see fit.