Trait FontProvider

Source

pub trait FontProvider {
    // Required methods
    fn pixel_type(&self) -> PixelType;
    fn single_glyph(&self, character: char) -> Glyph;
    fn glyphs(&self, string: &str, glyphs: &mut Vec<Glyph>);
    fn line_height(&self) -> f32;
    fn metrics(&self, glyph: Glyph) -> Metrics;
    fn rasterize(&self, glpyh: Glyph) -> Result<Vec<u8>, CacheError>;

    // Provided method
    fn kerning(&self, _a: Glyph, _b: Glyph) -> f32 { ... }
}

Expand description

Any object that can turn characters into glyphs and render them can be a FontProvider

FontProviders can be TTF font rasters, like rusttype (a pure-Rust library for decoding fonts) or fontkit (a library that delegates to system APIs to handle fonts). Other FontProviders could include bitmap fonts, or a combination of libraries (like a library to handle shaping and another library to handle rendering.)

It is assumed that a given font provider will operate at a fixed size. For a variable-sized source (like a TTF font), the font size can be paired with the font data to produce a single FontProvider.