thomaskrause
commented
10 months ago I also experimented with cosmic text but went with hacking some completely inefficient and not really generic code in the tessellate_text function of the epaint Tessellator.
pub fn tessellate_text(&mut self, text_shape: &TextShape, out: &mut Mesh) {
let TextShape {
pos: galley_pos,
galley,
underline,
override_text_color,
angle,
} = text_shape;
if galley.is_empty() {
return;
}
if galley.pixels_per_point != self.pixels_per_point {
eprintln!("epaint: WARNING: pixels_per_point (dpi scale) have changed between text layout and tessellation. \
You must recreate your text shapes if pixels_per_point changes.");
}
for row in &galley.rows {
let metrics =
cosmic_text::Metrics::new(galley.job.sections[0].format.font_id.size, row.height());
let mut buffer = cosmic_text::Buffer::new(&mut self.font_system, metrics);
let mut buffer = buffer.borrow_with(&mut self.font_system);
buffer.set_size(row.rect.width(), row.rect.height());
let attrs = cosmic_text::Attrs::new();
buffer.set_text(&row.text(), attrs, cosmic_text::Shaping::Advanced);
buffer.shape_until_scroll();
let text_color = override_text_color
.map(|c| cosmic_text::Color::rgba(c.r(), c.g(), c.b(), c.a()))
.unwrap_or_else(|| cosmic_text::Color::rgb(0xFF, 0xFF, 0xFF));
buffer.draw(&mut self.swash_cache, text_color, |x, y, w, h, color| {
let min_pos = *galley_pos + row.rect.min.to_vec2() + vec2(x as f32, y as f32);
let size = vec2(w as f32, h as f32);
let output_rect = Rect::from_min_size(min_pos, size);
let ecolor =
Color32::from_rgba_unmultiplied(color.r(), color.g(), color.b(), color.a());
out.add_colored_rect(output_rect, ecolor);
});
}
}Using cosmic text would mean to replace the whole pipeline of text layout and not just rendering, which seems to be quite a change, even possible in the public facing API. But it is definitely possible.
ElhamAryanpur
emilk
dignifiedquire
mikeandmore
StratusFearMe21
crumblingstatue
jackpot51
torokati44
parasyte
As discussed in #1016 , I have done some testing on cosmic-text.
First of all, they have some docs that I've been exploring. And I was testing their example. They do have
no_stdandwasmsupport too according to theCargo.tomlthey have.I've noticed that the way it renders, is by drawing rectangles. Which is something I've seen for the first time to be honest. You can check it here. It gives a x,y,width,height, and color which is usually just color predefined and alpha channel being different for aliasing and stuff.
There is also another method if rectangles aren't possible: Swash Image which basically returns an image bytes to be rendered instead of individually creating rectangles. It requires some things I couldn't implement myself to be honest.
I was able to sort of hack the rectangle method in my engine
It had... not good results to be honest
Although maybe that's on me for having some issues with the engine as their examples do work and work very well. But yeah, that's my findings so far on cosmic text.