use rusttype;
pub type Font = rusttype::Font<'static>;
pub struct Text {
pub bytes: Vec<u8>,
pub size: (u32, u32),
}
impl Text {
pub fn new(text: &str, font: &Font, height: f32) -> Self {
let scale = rusttype::Scale::uniform(height);
let offset = rusttype::point(0.0, font.v_metrics(scale).ascent);
let glyphs: Vec<_> = font.layout(text, scale, offset).collect();
let width = glyphs.last().unwrap().pixel_bounding_box().unwrap().max.x;
let height = height.ceil();
let size = (width as u32, height as u32);
let bytes = Text::render(&glyphs, size);
Self { bytes, size }
}
fn render(glyphs: &[rusttype::PositionedGlyph], size: (u32, u32)) -> Vec<u8> {
let width = size.0 as usize;
let height = size.1 as usize;
let mut bytes = vec![0_u8; 4 * width * height];
let mapping_scale = 255.0;
for glyph in glyphs.iter() {
if let Some(bbox) = glyph.pixel_bounding_box() {
glyph.draw(|x, y, alpha| {
let alpha = (alpha * mapping_scale + 0.5) as u8;
let x = x as i32 + bbox.min.x;
let y = y as i32 + bbox.min.y;
if alpha > 0 && x >= 0 && x < width as i32 && y >= 0 && y < height as i32 {
let i = (x as usize + y as usize * width) * 4;
bytes[i] = 255;
bytes[i + 1] = 255;
bytes[i + 2] = 255;
bytes[i + 3] = alpha;
}
});
}
}
bytes
}
}