clay-zig-bindings/README.md
2025-03-18 23:02:55 +01:00

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### Zig Bindings for clay.h
![Screenshot from 2025-01-07 17-05-01](https://github.com/user-attachments/assets/8f38e8bf-00aa-4e16-be96-b7a0d81f4313)
This repository contains Zig bindings for the [clay UI layout library](https://github.com/nicbarker/clay), as well as an example implementation of the [clay website](https://nicbarker.com/clay) in Zig.
This README is abbreviated and applies to using clay in Zig specifically: If you haven't taken a look at the [full documentation for clay](https://github.com/nicbarker/clay/blob/main/README.md), it's recommended that you take a look there first to familiarise yourself with the general concepts.
Some differences between the C API and the Zig bindings include:
- minor naming changes
- ability to initialize a parameter by calling a function that is part of its type's namespace for example `.fixed()` or `.layout()`
- ability to initialize a parameter by using a public constant that is part of its type's namespace for example `.grow`
In C:
```C
CLAY({ // C macro for creating a scope
.id = CLAY_ID("SideBar"),
.layout = {
.layoutDirection = CLAY_TOP_TO_BOTTOM,
.sizing = { .width = CLAY_SIZING_FIXED(300), .height = CLAY_SIZING_GROW(0) },
.padding = CLAY_PADDING_ALL(16),
.childAlignment = .{ .x = CLAY_ALIGN_X_CENTER , .y = .CLAY_ALIGN_Y_TOP },
.childGap = 16
},
.backgroundColor = COLOR_LIGHT
}){
// Child elements here
}
```
In Zig:
```Zig
clay.UI()(.{ // function call for creating a scope
.id = .ID("SideBar"),
.layout = .{
.direction = .top_to_bottom,
.sizing = .{ .w = .fixed(300), .h = .grow },
.padding = .all(16),
.child_alignment = .{ .x = .center, .y = .top },
.child_gap = 16,
},
.background_color = light_grey,
})({
// Child elements here
});
```
## installation:
Compatible Zig Version: `0.14.0`
1. Add `zclay` to the dependency list in `build.zig.zon`:
```sh
zig fetch --save git+https://github.com/johan0A/clay-zig-bindings#v0.13
```
2. Config `build.zig`:
```zig
...
const zclay_dep = b.dependency("zclay", .{
.target = target,
.optimize = optimize,
});
compile_step.root_module.addImport("zclay", zclay_dep.module("zclay"));
...
```
## quickstart
2. Ask clay for how much static memory it needs using [clay.minMemorySize()](https://github.com/nicbarker/clay/blob/main/README.md#clay_minmemorysize), create an Arena for it to use with [clay.createArenaWithCapacityAndMemory(minMemorySize, memory)](https://github.com/nicbarker/clay/blob/main/README.md#clay_createarenawithcapacityandmemory), and initialize it with [clay.Initialize(arena)](https://github.com/nicbarker/clay/blob/main/README.md#clay_initialize).
```zig
const min_memory_size: u32 = clay.minMemorySize();
const memory = try allocator.alloc(u8, min_memory_size);
defer allocator.free(memory);
const arena: clay.Arena = clay.createArenaWithCapacityAndMemory(memory);
_ = clay.initialize(arena, .{ .h = 1000, .w = 1000 }, .{});
clay.setMeasureTextFunction(void, {}, renderer.measureText);
```
3. Provide a `measureText(text, config)` function with [clay.setMeasureTextFunction(function)](https://github.com/nicbarker/clay/blob/main/README.md#clay_setmeasuretextfunction) so that clay can measure and wrap text.
```zig
// Example measure text function
pub fn measureText(clay_text: []const u8, config: *clay.TextElementConfig, user_data: void) clay.Dimensions {
// clay.TextElementConfig contains members such as fontId, fontSize, letterSpacing etc
// Note: clay.String.chars is not guaranteed to be null terminated
}
// Tell clay how to measure text
clay.setMeasureTextFunction({}, measureText)
```
4. **Optional** - Call [clay.setPointerPosition(pointerPosition)](https://github.com/nicbarker/clay/blob/main/README.md#clay_setpointerposition) if you want to use mouse interactions.
```Zig
// Update internal pointer position for handling mouseover / click / touch events
clay.setPointerState(.{
.x = mouse_position_x,
.y = mouse_position_y,
}, is_left_mouse_button_down);
```
5. Call [clay.beginLayout()](https://github.com/nicbarker/clay/blob/main/README.md#clay_beginlayout) and declare your layout using the provided functions.
```Zig
const light_grey: clay.Color = .{ 224, 215, 210, 255 };
const red: clay.Color = .{ 168, 66, 28, 255 };
const orange: clay.Color = .{ 225, 138, 50, 255 };
const white: clay.Color = .{ 250, 250, 255, 255 };
const sidebar_item_layout: clay.LayoutConfig = .{ .sizing = .{ .w = .grow, .h = .fixed(50) } };
// Re-useable components are just normal functions
fn sidebarItemComponent(index: u32) void {
clay.UI()(.{
.id = .IDI("SidebarBlob", index),
.layout = sidebar_item_layout,
.background_color = orange,
})({});
}
// An example function to begin the "root" of your layout tree
fn createLayout(profile_picture: *const rl.Texture2D) clay.ClayArray(clay.RenderCommand) {
clay.beginLayout();
clay.UI()(.{
.id = .ID("OuterContainer"),
.layout = .{ .direction = .left_to_right, .sizing = .grow, .padding = .all(16), .child_gap = 16 },
.background_color = white,
})({
clay.UI()(.{
.id = .ID("SideBar"),
.layout = .{
.direction = .top_to_bottom,
.sizing = .{ .h = .grow, .w = .fixed(300) },
.padding = .all(16),
.child_alignment = .{ .x = .center, .y = .top },
.child_gap = 16,
},
.background_color = light_grey,
})({
clay.UI()(.{
.id = .ID("ProfilePictureOuter"),
.layout = .{ .sizing = .{ .w = .grow }, .padding = .all(16), .child_alignment = .{ .x = .left, .y = .center }, .child_gap = 16 },
.background_color = red,
})({
clay.UI()(.{
.id = .ID("ProfilePicture"),
.layout = .{ .sizing = .{ .h = .fixed(60), .w = .fixed(60) } },
.image = .{ .source_dimensions = .{ .h = 60, .w = 60 }, .image_data = @ptrCast(profile_picture) },
})({});
clay.text("Clay - UI Library", .{ .font_size = 24, .color = light_grey });
});
for (0..5) |i| sidebarItemComponent(@intCast(i));
});
clay.UI()(.{
.id = .ID("MainContent"),
.layout = .{ .sizing = .grow },
.background_color = light_grey,
})({
//...
});
});
return clay.endLayout();
}
```
6. Call [clay.endLayout()](https://github.com/nicbarker/clay/blob/main/README.md#clay_endlayout) and process the resulting [clay.RenderCommandArray](https://github.com/nicbarker/clay/blob/main/README.md#clay_rendercommandarray) in your choice of renderer.
```zig
pub fn clayRaylibRender(render_commands: *clay.ClayArray(clay.RenderCommand), allocator: std.mem.Allocator) void {
var i: usize = 0;
while (i < render_commands.length) : (i += 1) {
const render_command = clay.renderCommandArrayGet(render_commands, @intCast(i));
const bounding_box = render_command.bounding_box;
switch (render_command.command_type) {
.none => {},
.text => {
...
```
Please see the [full C documentation for clay](https://github.com/nicbarker/clay/blob/main/README.md) for API details and the example folder in this repo. All public C functions and Macros have Zig binding equivalents, generally of the form `Clay_BeginLayout` (C) -> `clay.beginLayout` (zig)