Lyon

GPU-based 2D graphics rendering in rust.

Motivation

For now the goal is to provide efficient SVG-compliant path tessellation tools to help with rendering vector graphics on the GPU. For now think of this library as a way to turn complex paths into triangles for use in your own rendering engine.

The intent is for this library to be useful in projects like Servo and games.

Example

    // Build a Path.
    let mut builder = SvgPathBuilder::new(Path::builder());
    builder.move_to(point(0.0, 0.0));
    builder.line_to(point(1.0, 0.0));
    builder.quadratic_bezier_to(point(2.0, 0.0), point(2.0, 1.0));
    builder.cubic_bezier_to(point(1.0, 1.0), point(0.0, 1.0), point(0.0, 0.0));
    builder.close();
    let path = builder.build();

    // Will contain the result of the tessellation.
    let mut geometry_cpu: VertexBuffers<Vec2> = VertexBuffers::new();

    let mut tessellator = FillTessellator::new();

    {
        // The simple builder uses the tessellator's vertex type.
        // You can implement the GeometryBuilder trait to create custom vertices.
        let mut vertex_builder = simple_builder(&mut geometry_cpu);

        // Compute the tessellation.
        tessellator.tessellate_path(
            path.path_iter().flattened(0.1),
            &FillOptions::default(),
            &mut vertex_builder
        ).unwrap();
    }

    // The tessellated geometry is ready to be uploaded to the GPU.
    println!(" -- {} vertices {} indices",
        geometry_cpu.vertices.len(),
        geometry_cpu.indices.len()
    );

Structure

The project is split into small crates:

• - lyon_tessellation - Path tessellation routines.
• - lyon_path_builder - Tools to facilitate building paths.
• - lyon_path_iterator - Tools to facilitate iteratring over paths.
• - lyon_path - A simple optional path data structure, provided for convenience.
• - lyon_bezier - Cubic and Quadratic 2d bezier math.
• - lyon_extra - Additional testing and debugging tools.
• - lyon_core - Common types to most lyon crates.

There is also a toy command-line tool to tessellate SVG path from your favorite terminal.

Have a look at the gfx-rs example to see how integrating the tessellators in a renderer can look like.

TODO

There's a rough list of things to do in the wiki. If you are interested in contributing, please let me know on twitter (@nicalsilva) or by e-mail.

License

Licensed under either of

• Apache License, Version 2.0 (LICENSE-APACHE or http://www.apache.org/licenses/LICENSE-2.0)
• MIT license (LICENSE-MIT or http://opensource.org/licenses/MIT)

at your option.

Contribution

Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.