cosmic-text/src/font/layout.rs
2022-10-18 17:14:03 -06:00

97 lines
3.6 KiB
Rust

use crate::TextLineIndex;
use super::{CacheKey, Font};
pub struct FontLayoutGlyph<'a> {
pub start: usize,
pub end: usize,
pub x: f32,
pub w: f32,
pub font: &'a Font<'a>,
pub inner: (CacheKey, i32, i32),
}
pub struct FontLayoutLine<'a> {
pub line_i: TextLineIndex,
pub glyphs: Vec<FontLayoutGlyph<'a>>,
}
impl<'a> FontLayoutLine<'a> {
pub fn draw<F: FnMut(i32, i32, u32)>(&self, base: u32, mut f: F) {
for glyph in self.glyphs.iter() {
use swash::scale::{Render, Source, StrikeWith};
use swash::zeno::{Format, Vector};
let mut cache = glyph.font.cache.lock().unwrap();
let (cache_key, x_int, y_int) = glyph.inner;
let image_opt = cache.entry(cache_key).or_insert_with(|| {
let mut scale_context = glyph.font.scale_context.lock().unwrap();
// Build the scaler
let mut scaler = scale_context
.builder(glyph.font.swash)
.size(cache_key.font_size as f32)
.hint(true)
.build();
// Compute the fractional offset-- you'll likely want to quantize this
// in a real renderer
let offset =
Vector::new(cache_key.x_bin.as_float(), cache_key.y_bin.as_float());
// Select our source order
Render::new(&[
// Color outline with the first palette
Source::ColorOutline(0),
// Color bitmap with best fit selection mode
Source::ColorBitmap(StrikeWith::BestFit),
// Standard scalable outline
Source::Outline,
])
// Select a subpixel format
.format(Format::Alpha)
// Apply the fractional offset
.offset(offset)
// Render the image
.render(&mut scaler, cache_key.glyph_id)
});
if let Some(ref image) = image_opt {
use swash::scale::image::Content;
let x = x_int + image.placement.left;
let y = y_int - image.placement.top;
match image.content {
Content::Mask => {
let mut i = 0;
for off_y in 0..image.placement.height as i32 {
for off_x in 0..image.placement.width as i32 {
let color = (image.data[i] as u32) << 24 | base & 0xFFFFFF;
f(x + off_x, y + off_y, color);
i += 1;
}
}
}
Content::Color => {
let mut i = 0;
for off_y in 0..image.placement.height as i32 {
for off_x in 0..image.placement.width as i32 {
let color = (image.data[i + 3] as u32) << 24
| (image.data[i] as u32) << 16
| (image.data[i + 1] as u32) << 8
| (image.data[i + 2] as u32);
f(x + off_x, y + off_y, color);
i += 4;
}
}
}
Content::SubpixelMask => {
log::warn!("TODO: SubpixelMask");
}
}
}
}
}
}