Crate hieroglyph

A font-embedded text renderer for obscure characters, scripts, and emojis, built for maximum portability.

This crate enables rendering of virtually any Unicode character, including rare scripts and emojis, without relying on system fonts or external resources. It’s powered by cosmic-text for shaping and layout, with bundled Noto fonts and emoji assets via twemoji-assets.

All assets are included in the binary, which increases its size (~35MB in release builds), but ensures the renderer works in any environment, even minimal ones like Docker scratch images or embedded systems without font support.

Rendering

Rendering is decoupled from any specific imaging or graphics backend. Instead, DrawingContext offers a draw method that invokes a user-provided callback for each pixel, giving its (x, y) coordinate and color.

Usage

A minimal setup requires:

• A DrawingContext (can be reused across frames or content with the same settings),
• A Segments object, which holds the segmented input text to render.

Example

The examples/example.rs showcasing how the image crate may be used to render very obscure characters onto a canvas.

use hieroglyph::{DrawingContext, Segments};
use image::{Pixel, Rgba, RgbaImage};

fn main() {
    let name = "🅱 Jäne H🅱oe Bib 🦆 🇩🇪 🗕 🗗 🗙 𓁹‿𓁹 ♛";
    let segments = Segments::new(name);
    let mut ctx = DrawingContext::new();
    ctx.rgb(255, 255, 255);
    ctx.font_size(50.0);

    let mut canvas = RgbaImage::new(ctx.width(&segments), 55);
    ctx.draw(&segments, |(x, y), rgba| {
        let color = Rgba(rgba);
        let Ok(x) = x.try_into() else { return };
        let Ok(y) = y.try_into() else { return };
        let Some(pixel) = canvas.get_pixel_checked(x, y) else {
            return;
        };
        let mut pixel = pixel.clone();
        pixel.blend(&color);
        canvas.put_pixel(x, y, pixel);
    });

    canvas.save("examples/example.png").unwrap();
}

Note

Line breaks (\n) are currently not supported.

Modules

fonts

This module contains all the fonts included in hieroglyph.

Structs

DrawingContext

Context for drawing on arbitrary pixel buffers.

DrawingContextBuilder

A builder to configure a new DrawingContext.

EmojiSegment

EmojiSegment represents a single emoji from the input string.

Segments

Iterator over grapheme clusters and text segments of a string.

TextSegment

TextSegment holds a reference to a snippet of the input string.

Enums

FontOrder

Determines the priority order of fonts when rendering characters.

Segment

Segment represents either a text or an emoji segment.