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Add cosmic-text as an option for the text renderer
Cosmic-text is still changing somewhat rapidly, but should provide a way to handle RTL/bidir/etc text with proper shaping. So I thought I'd try adding support for it here. This isn't quite working right when I try it with Arabic text (maybe partly that it needs alpha blending when compositing glyphs?). And it needs to request the right font.
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,139 @@ | ||
| use crate::title::{config, font_preference::FontPreference}; | ||
| use cosmic_text::{ | ||
| Attrs, AttrsList, BufferLine, Color as CosmicColor, Family, FontSystem, Metrics, SwashCache, | ||
| Wrap, | ||
| }; | ||
| use once_cell::sync::Lazy; | ||
| use tiny_skia::{Color, ColorU8, Pixmap, PremultipliedColorU8}; | ||
|
|
||
| // Use arbitrarily large width, then calculate max/min x from resulting glyphs | ||
| const MAX_WIDTH: i32 = 1024 * 1024; | ||
|
|
||
| // Needs static lifetime due to limitations in cosmic-text/rustybuzz | ||
| static FONT_SYSTEM: Lazy<FontSystem> = Lazy::new(|| FontSystem::new()); | ||
|
|
||
| fn attrs_from_font_pref(font_preference: &FontPreference) -> Attrs { | ||
| let attrs = Attrs::new().family(Family::Name(&font_preference.name)); | ||
| if let Some(style) = &font_preference.style { | ||
| // TODO | ||
| } | ||
| attrs | ||
| } | ||
|
|
||
| pub struct CosmicTextTitleText { | ||
| buffer_line: BufferLine, | ||
| cache: SwashCache<'static>, | ||
| color: Color, | ||
| scale: u32, | ||
| pixmap: Option<Pixmap>, | ||
| font_pref: FontPreference, | ||
| } | ||
|
|
||
| impl std::fmt::Debug for CosmicTextTitleText { | ||
| fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result { | ||
| f.debug_struct("TitleText") | ||
| .field("color", &self.color) | ||
| .field("scale", &self.scale) | ||
| .field("pixmap", &self.pixmap) | ||
| .field("font_pref", &self.font_pref) | ||
| .finish() | ||
| } | ||
| } | ||
|
|
||
| impl CosmicTextTitleText { | ||
| pub fn new(color: Color) -> Self { | ||
| let buffer_line = BufferLine::new("", AttrsList::new(Attrs::new())); | ||
| let cache = SwashCache::new(&FONT_SYSTEM); | ||
| let font_pref = config::titlebar_font().unwrap_or_default(); | ||
| Self { | ||
| buffer_line, | ||
| cache, | ||
| color, | ||
| scale: 1, | ||
| pixmap: None, | ||
| font_pref, | ||
| } | ||
| } | ||
|
|
||
| pub fn update_scale(&mut self, scale: u32) { | ||
| self.scale = scale; | ||
| self.update_pixmap(); | ||
| } | ||
|
|
||
| pub fn update_title<S: Into<String>>(&mut self, title: S) { | ||
| let attrs = attrs_from_font_pref(&self.font_pref); | ||
| self.buffer_line | ||
| .set_text(title.into(), AttrsList::new(attrs)); | ||
| self.update_pixmap(); | ||
| } | ||
|
|
||
| pub fn update_color(&mut self, color: Color) { | ||
| self.color = color; | ||
| self.update_pixmap(); | ||
| } | ||
|
|
||
| pub fn pixmap(&self) -> Option<&Pixmap> { | ||
| self.pixmap.as_ref() | ||
| } | ||
|
|
||
| fn update_pixmap(&mut self) { | ||
| self.pixmap = None; | ||
|
|
||
| let shape_line = self.buffer_line.shape(&FONT_SYSTEM); | ||
|
|
||
| let height = (1.4 * self.scale as f32 * self.font_pref.pt_size * 96.0 / 72.0).ceil() as i32; // ? | ||
| let layout_lines = shape_line.layout(height, MAX_WIDTH, Wrap::Word); | ||
| let layout_line = &layout_lines[0]; | ||
| let min_x = layout_line | ||
| .glyphs | ||
| .iter() | ||
| .map(|i| i.x.floor() as u32) | ||
| .min() | ||
| .unwrap_or(0); | ||
| let width = layout_line.w.ceil() as u32; | ||
|
|
||
| let mut pixmap = match Pixmap::new(width, height as u32) { | ||
| Some(pixmap) => pixmap, | ||
| None => return, | ||
| }; | ||
| let pixels = pixmap.pixels_mut(); | ||
|
|
||
| let color = self.color.to_color_u8(); | ||
| let color = CosmicColor::rgba(color.red(), color.green(), color.blue(), color.alpha()); | ||
| for glyph in &layout_line.glyphs { | ||
| let (cache_key, x_int, y_int) = (glyph.cache_key, glyph.x_int, glyph.y_int); | ||
| self.cache | ||
| .with_pixels(cache_key, color, |pixel_x, pixel_y, color| { | ||
| if color.a() == 0 { | ||
| return; | ||
| } | ||
|
|
||
| let y = height + y_int + pixel_y; | ||
| let x = x_int + pixel_x - min_x as i32; | ||
| let idx = y * width as i32 + x; | ||
| if idx >= 0 && (idx as usize) < pixels.len() { | ||
| let idx = idx as usize; | ||
| let color = ColorU8::from_rgba(color.r(), color.g(), color.b(), color.a()); | ||
| pixels[idx] = alpha_blend(color.premultiply(), pixels[idx]); | ||
| } | ||
| }); | ||
| } | ||
|
|
||
| self.pixmap = Some(pixmap); | ||
| } | ||
| } | ||
|
|
||
| // `a` over `b` | ||
| // This should be correct but not especially efficient. | ||
| fn alpha_blend(a: PremultipliedColorU8, b: PremultipliedColorU8) -> PremultipliedColorU8 { | ||
| let blend_channel = |channel_a: u8, channel_b: u8| -> u8 { | ||
| channel_a.saturating_add(channel_b.saturating_mul(255 - a.alpha())) | ||
| }; | ||
| PremultipliedColorU8::from_rgba( | ||
| blend_channel(a.red(), b.red()), | ||
| blend_channel(a.green(), b.green()), | ||
| blend_channel(a.blue(), b.blue()), | ||
| blend_channel(a.alpha(), b.alpha()), | ||
| ) | ||
| .unwrap() | ||
| } |