This is a simple immediate mode UI written in Odin as an exploratory exercise in recreational programming.

For layout this package uses a small Clay-inspired tree layout. Widgets are declared as a tree, fixed-size leaves and intrinsic-size labels are measured, parents compute their size from their children, and then children are positioned with a parent direction, main_align, cross_align, padding, and gap. Layout reserves space for widget borders so they are not clipped by parents. Rendering commands are emitted after layout has resolved widget rectangles.

theme := ui.theme_light(font)
ui.init(ctx, theme = theme)
ui.text_measure_init(ctx, nil, measure_width)

ui.begin(ctx, width, height, ui.layout_fixed(width, height, .Column, .Center, .Center))
defer ui.end(ctx)

th := ctx.theme
ui.panel_begin(
	ctx,
	ui.layout_auto(
		.Column,
		.Start,
		.Center,
		padding = ui.Inset{top = th.spacing.xl, right = th.spacing.xl, bottom = th.spacing.xl, left = th.spacing.xl},
		gap = th.spacing.xl,
	),
)
defer ui.panel_end(ctx)

ui.label(ctx, "Layout showcase", role = .Title)
ui.button(ctx, ui.layout_fixed(170, 42), "Click me!")

Rendering uses a Command queue design where widgets are iterated starting from the root following a Breadth-First Search (BFS) pattern. For each widget, one or more Commands to draw are pushed into the queue. The queue can then be iterated and drawn by any graphical engine. Currently the demo uses Raylib.

The name exigent means "requiring immediate action".

This sample contains all the available widgets so far.

This repo includes an optional karl2d_exigent package that renders Exigent commands through Karl2D. Core Exigent does not import Karl2D; only the adapter and demos/karl2d do.

For local development, Karl2D is checked out as a git submodule under lib/:

git submodule update --init --recursive

The adapter uses collection imports so downstream projects can point karl2d at their own submodule and avoid duplicate Karl2D package identities:

import ui "exigent:."
import k2 "karl2d:."
import kx "karl2d_exigent:."

Run the Karl2D demo from the repo root:

./demos/karl2d/run.sh

For a downstream project, use the same collection names but point them at that project's checkouts:

odin run . \
	-collection:exigent=/path/to/exigent \
	-collection:karl2d=/path/to/project/lib/karl2d \
	-collection:karl2d_exigent=/path/to/exigent/karl2d_exigent

Karl2D currently exposes key and mouse events, but not dedicated text-input character events. The adapter feeds key/mouse events directly and synthesizes basic ASCII character events from key presses for Exigent text inputs.

This repo also includes an optional raylib_exigent package that renders Exigent commands through vendor:raylib, translates Raylib input into Exigent events, measures text through Raylib fonts, and maps Raylib textures to Exigent sprite handles.

Run the Raylib demo from the repo root:

./demos/raylib/run.sh

For a downstream Raylib project:

odin run . \
	-collection:exigent=/path/to/exigent \
	-collection:raylib_exigent=/path/to/exigent/raylib_exigent

The adapter owns textures loaded through its load_sprite_* helpers when destroy(renderer, true) is used. Textures registered from a game-owned asset cache can use destroy(renderer, false) so the game keeps lifetime ownership.