Nuklear README

The project's README from github.com/Immediate-Mode-UI/Nuklear. As one markdown file: README.md.

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 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

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 #includeing this file, e.g.:

#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.

screenshot screen screen2 node skinning gamepad

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:

/* 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 folder, each with its own build instructions, e.g.:

make -C demo/glfw_opengl3

More complete programs can be found in the example folder. Rendered by one of the backends, the interface built above looks like this:

example

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:

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 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 which restored my faith in libraries and brought me to create some of my own. Finally Apoorva Joshi for his single-header file packer.

License

Nuklear is avaliable under either the MIT License or public domain. See LICENSE for more info.

Nuklear (Immediate-Mode-UI/Nuklear)

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11.5K ·GitHub
Nuklear
What is this?Nuklear is a minimal-state, immediate-mode graphical user interface toolkit written in ANSI C, designed as a simple embeddable UI that you build into your own application.
Is it a library I compile into my app, or a standalone program?A single-header C library. It only handles the UI itself: there is no built-in render backend and no OS window or input handling — wiring those up is your part.
How do I add it to my project?Copy the single header. Header-only mode is the default; to compile the implementation, define NK_IMPLEMENTATION in one .c/.cpp file before including nuklear.h.
Do I need to install any other libraries first?No. It has zero dependencies — you can even build it without the C standard library — and the whole codebase is only about 18k lines of C89.
Are there any gotchas when setting it up?Yes. Every include of nuklear.h must define the same optional flags; mixing them up causes compiler errors or, worse, stack corruption.
If it does not draw anything itself, how do I get it on screen?You plug in a rendering backend. The demo folder ships ready-to-use backends for GLFW, SDL, X11, GDI, Direct3D and Vulkan, each with its own build instructions.
Is there anything unusual about the license?It is very permissive: you can take it under the MIT License or as public domain, whichever suits your project.
How is Nuklear related to Dear ImGui?The author credits Omar Cornut's imgui library as the direct inspiration. Nuklear takes the same immediate-mode idea and implements it from scratch in ANSI C as a small (~18k LOC), dependency-free single header.
What does writing an app with it look like?One-time setup, then every frame you mirror your input into Nuklear, build the interface, and draw its commands through your rendering backend — the README example shows exactly this structure.
Can I use it from languages other than C?Yes, via community bindings for Java, D, Go, Rust, Nim, Lua, Python, C#/.NET, V and more. They are maintained by other authors, so their quality and how up to date they are varies.
How much control do I have over memory and looks?A lot: it is fully skinnable and customizable, has a low memory footprint with total control of memory usage, no global or hidden state, optional font baker and vertex buffer output, plus UTF-8 support.
What are similar projects?nuklear, imgui, sokol, DearPyGui, iced, cJSON, bgfx, DEsk
Which topics is it in?single-header-lib, imgui, multiplatform, directx, header-only, x11, toolkit, no-dependencies, vulkan, embedded, graphics, c
Creator
Immediate-Mode-UI
Size
21.1 MB
Stars
11.5K
Updated
CommitSep 20Releasev4.13.3May 05
Age
6y
Commits · 90 Days