1use crate::{
2 Bounds, DevicePixels, Font, FontFeatures, FontId, FontMetrics, FontRun, FontStyle, FontWeight,
3 GlyphId, LineLayout, Pixels, PlatformTextSystem, Point, RenderGlyphParams, SUBPIXEL_VARIANTS,
4 ShapedGlyph, ShapedRun, SharedString, Size, point, size,
5};
6use anyhow::{Context as _, Ok, Result};
7use collections::HashMap;
8use cosmic_text::{
9 Attrs, AttrsList, CacheKey, Family, Font as CosmicTextFont, FontFeatures as CosmicFontFeatures,
10 FontSystem, ShapeBuffer, ShapeLine, SwashCache,
11};
12
13use itertools::Itertools;
14use parking_lot::RwLock;
15use pathfinder_geometry::{
16 rect::{RectF, RectI},
17 vector::{Vector2F, Vector2I},
18};
19use smallvec::SmallVec;
20use std::{borrow::Cow, sync::Arc};
21
22pub(crate) struct CosmicTextSystem(RwLock<CosmicTextSystemState>);
23
24#[derive(Debug, Clone, PartialEq, Eq, Hash)]
25struct FontKey {
26 family: SharedString,
27 features: FontFeatures,
28}
29
30impl FontKey {
31 fn new(family: SharedString, features: FontFeatures) -> Self {
32 Self { family, features }
33 }
34}
35
36struct CosmicTextSystemState {
37 swash_cache: SwashCache,
38 font_system: FontSystem,
39 scratch: ShapeBuffer,
40 /// Contains all already loaded fonts, including all faces. Indexed by `FontId`.
41 loaded_fonts: Vec<LoadedFont>,
42 /// Caches the `FontId`s associated with a specific family to avoid iterating the font database
43 /// for every font face in a family.
44 font_ids_by_family_cache: HashMap<FontKey, SmallVec<[FontId; 4]>>,
45}
46
47struct LoadedFont {
48 font: Arc<CosmicTextFont>,
49 features: CosmicFontFeatures,
50 is_known_emoji_font: bool,
51}
52
53impl CosmicTextSystem {
54 pub(crate) fn new() -> Self {
55 // todo(linux) make font loading non-blocking
56 let mut font_system = FontSystem::new();
57
58 Self(RwLock::new(CosmicTextSystemState {
59 font_system,
60 swash_cache: SwashCache::new(),
61 scratch: ShapeBuffer::default(),
62 loaded_fonts: Vec::new(),
63 font_ids_by_family_cache: HashMap::default(),
64 }))
65 }
66}
67
68impl Default for CosmicTextSystem {
69 fn default() -> Self {
70 Self::new()
71 }
72}
73
74impl PlatformTextSystem for CosmicTextSystem {
75 fn add_fonts(&self, fonts: Vec<Cow<'static, [u8]>>) -> Result<()> {
76 self.0.write().add_fonts(fonts)
77 }
78
79 fn all_font_names(&self) -> Vec<String> {
80 let mut result = self
81 .0
82 .read()
83 .font_system
84 .db()
85 .faces()
86 .filter_map(|face| face.families.first().map(|family| family.0.clone()))
87 .collect_vec();
88 result.sort();
89 result.dedup();
90 result
91 }
92
93 fn font_id(&self, font: &Font) -> Result<FontId> {
94 // todo(linux): Do we need to use CosmicText's Font APIs? Can we consolidate this to use font_kit?
95 let mut state = self.0.write();
96 let key = FontKey::new(font.family.clone(), font.features.clone());
97 let candidates = if let Some(font_ids) = state.font_ids_by_family_cache.get(&key) {
98 font_ids.as_slice()
99 } else {
100 let font_ids = state.load_family(&font.family, &font.features)?;
101 state.font_ids_by_family_cache.insert(key.clone(), font_ids);
102 state.font_ids_by_family_cache[&key].as_ref()
103 };
104
105 // todo(linux) ideally we would make fontdb's `find_best_match` pub instead of using font-kit here
106 let candidate_properties = candidates
107 .iter()
108 .map(|font_id| {
109 let database_id = state.loaded_font(*font_id).font.id();
110 let face_info = state.font_system.db().face(database_id).expect("");
111 face_info_into_properties(face_info)
112 })
113 .collect::<SmallVec<[_; 4]>>();
114
115 let ix =
116 font_kit::matching::find_best_match(&candidate_properties, &font_into_properties(font))
117 .context("requested font family contains no font matching the other parameters")?;
118
119 Ok(candidates[ix])
120 }
121
122 fn font_metrics(&self, font_id: FontId) -> FontMetrics {
123 let metrics = self
124 .0
125 .read()
126 .loaded_font(font_id)
127 .font
128 .as_swash()
129 .metrics(&[]);
130
131 FontMetrics {
132 units_per_em: metrics.units_per_em as u32,
133 ascent: metrics.ascent,
134 descent: -metrics.descent, // todo(linux) confirm this is correct
135 line_gap: metrics.leading,
136 underline_position: metrics.underline_offset,
137 underline_thickness: metrics.stroke_size,
138 cap_height: metrics.cap_height,
139 x_height: metrics.x_height,
140 // todo(linux): Compute this correctly
141 bounding_box: Bounds {
142 origin: point(0.0, 0.0),
143 size: size(metrics.max_width, metrics.ascent + metrics.descent),
144 },
145 }
146 }
147
148 fn typographic_bounds(&self, font_id: FontId, glyph_id: GlyphId) -> Result<Bounds<f32>> {
149 let lock = self.0.read();
150 let glyph_metrics = lock.loaded_font(font_id).font.as_swash().glyph_metrics(&[]);
151 let glyph_id = glyph_id.0 as u16;
152 // todo(linux): Compute this correctly
153 // see https://github.com/servo/font-kit/blob/master/src/loaders/freetype.rs#L614-L620
154 Ok(Bounds {
155 origin: point(0.0, 0.0),
156 size: size(
157 glyph_metrics.advance_width(glyph_id),
158 glyph_metrics.advance_height(glyph_id),
159 ),
160 })
161 }
162
163 fn advance(&self, font_id: FontId, glyph_id: GlyphId) -> Result<Size<f32>> {
164 self.0.read().advance(font_id, glyph_id)
165 }
166
167 fn glyph_for_char(&self, font_id: FontId, ch: char) -> Option<GlyphId> {
168 self.0.read().glyph_for_char(font_id, ch)
169 }
170
171 fn glyph_raster_bounds(&self, params: &RenderGlyphParams) -> Result<Bounds<DevicePixels>> {
172 self.0.write().raster_bounds(params)
173 }
174
175 fn rasterize_glyph(
176 &self,
177 params: &RenderGlyphParams,
178 raster_bounds: Bounds<DevicePixels>,
179 ) -> Result<(Size<DevicePixels>, Vec<u8>)> {
180 self.0.write().rasterize_glyph(params, raster_bounds)
181 }
182
183 fn layout_line(&self, text: &str, font_size: Pixels, runs: &[FontRun]) -> LineLayout {
184 self.0.write().layout_line(text, font_size, runs)
185 }
186}
187
188impl CosmicTextSystemState {
189 fn loaded_font(&self, font_id: FontId) -> &LoadedFont {
190 &self.loaded_fonts[font_id.0]
191 }
192
193 #[profiling::function]
194 fn add_fonts(&mut self, fonts: Vec<Cow<'static, [u8]>>) -> Result<()> {
195 let db = self.font_system.db_mut();
196 for bytes in fonts {
197 match bytes {
198 Cow::Borrowed(embedded_font) => {
199 db.load_font_data(embedded_font.to_vec());
200 }
201 Cow::Owned(bytes) => {
202 db.load_font_data(bytes);
203 }
204 }
205 }
206 Ok(())
207 }
208
209 #[profiling::function]
210 fn load_family(
211 &mut self,
212 name: &str,
213 features: &FontFeatures,
214 ) -> Result<SmallVec<[FontId; 4]>> {
215 // TODO: Determine the proper system UI font.
216 let name = crate::text_system::font_name_with_fallbacks(name, "IBM Plex Sans");
217
218 let families = self
219 .font_system
220 .db()
221 .faces()
222 .filter(|face| face.families.iter().any(|family| *name == family.0))
223 .map(|face| (face.id, face.post_script_name.clone()))
224 .collect::<SmallVec<[_; 4]>>();
225
226 let mut loaded_font_ids = SmallVec::new();
227 for (font_id, postscript_name) in families {
228 let font = self
229 .font_system
230 .get_font(font_id)
231 .context("Could not load font")?;
232
233 // HACK: To let the storybook run and render Windows caption icons. We should actually do better font fallback.
234 let allowed_bad_font_names = [
235 "SegoeFluentIcons", // NOTE: Segoe fluent icons postscript name is inconsistent
236 "Segoe Fluent Icons",
237 ];
238
239 if font.as_swash().charmap().map('m') == 0
240 && !allowed_bad_font_names.contains(&postscript_name.as_str())
241 {
242 self.font_system.db_mut().remove_face(font.id());
243 continue;
244 };
245
246 let font_id = FontId(self.loaded_fonts.len());
247 loaded_font_ids.push(font_id);
248 self.loaded_fonts.push(LoadedFont {
249 font,
250 features: features.try_into()?,
251 is_known_emoji_font: check_is_known_emoji_font(&postscript_name),
252 });
253 }
254
255 Ok(loaded_font_ids)
256 }
257
258 fn advance(&self, font_id: FontId, glyph_id: GlyphId) -> Result<Size<f32>> {
259 let glyph_metrics = self.loaded_font(font_id).font.as_swash().glyph_metrics(&[]);
260 Ok(Size {
261 width: glyph_metrics.advance_width(glyph_id.0 as u16),
262 height: glyph_metrics.advance_height(glyph_id.0 as u16),
263 })
264 }
265
266 fn glyph_for_char(&self, font_id: FontId, ch: char) -> Option<GlyphId> {
267 let glyph_id = self.loaded_font(font_id).font.as_swash().charmap().map(ch);
268 if glyph_id == 0 {
269 None
270 } else {
271 Some(GlyphId(glyph_id.into()))
272 }
273 }
274
275 fn raster_bounds(&mut self, params: &RenderGlyphParams) -> Result<Bounds<DevicePixels>> {
276 let font = &self.loaded_fonts[params.font_id.0].font;
277 let subpixel_shift = params
278 .subpixel_variant
279 .map(|v| v as f32 / (SUBPIXEL_VARIANTS as f32 * params.scale_factor));
280 let image = self
281 .swash_cache
282 .get_image(
283 &mut self.font_system,
284 CacheKey::new(
285 font.id(),
286 params.glyph_id.0 as u16,
287 (params.font_size * params.scale_factor).into(),
288 (subpixel_shift.x, subpixel_shift.y.trunc()),
289 cosmic_text::CacheKeyFlags::empty(),
290 )
291 .0,
292 )
293 .clone()
294 .with_context(|| format!("no image for {params:?} in font {font:?}"))?;
295 Ok(Bounds {
296 origin: point(image.placement.left.into(), (-image.placement.top).into()),
297 size: size(image.placement.width.into(), image.placement.height.into()),
298 })
299 }
300
301 #[profiling::function]
302 fn rasterize_glyph(
303 &mut self,
304 params: &RenderGlyphParams,
305 glyph_bounds: Bounds<DevicePixels>,
306 ) -> Result<(Size<DevicePixels>, Vec<u8>)> {
307 if glyph_bounds.size.width.0 == 0 || glyph_bounds.size.height.0 == 0 {
308 anyhow::bail!("glyph bounds are empty");
309 } else {
310 let bitmap_size = glyph_bounds.size;
311 let font = &self.loaded_fonts[params.font_id.0].font;
312 let subpixel_shift = params
313 .subpixel_variant
314 .map(|v| v as f32 / (SUBPIXEL_VARIANTS as f32 * params.scale_factor));
315 let mut image = self
316 .swash_cache
317 .get_image(
318 &mut self.font_system,
319 CacheKey::new(
320 font.id(),
321 params.glyph_id.0 as u16,
322 (params.font_size * params.scale_factor).into(),
323 (subpixel_shift.x, subpixel_shift.y.trunc()),
324 cosmic_text::CacheKeyFlags::empty(),
325 )
326 .0,
327 )
328 .clone()
329 .with_context(|| format!("no image for {params:?} in font {font:?}"))?;
330
331 if params.is_emoji {
332 // Convert from RGBA to BGRA.
333 for pixel in image.data.chunks_exact_mut(4) {
334 pixel.swap(0, 2);
335 }
336 }
337
338 Ok((bitmap_size, image.data))
339 }
340 }
341
342 /// This is used when cosmic_text has chosen a fallback font instead of using the requested
343 /// font, typically to handle some unicode characters. When this happens, `loaded_fonts` may not
344 /// yet have an entry for this fallback font, and so one is added.
345 ///
346 /// Note that callers shouldn't use this `FontId` somewhere that will retrieve the corresponding
347 /// `LoadedFont.features`, as it will have an arbitrarily chosen or empty value. The only
348 /// current use of this field is for the *input* of `layout_line`, and so it's fine to use
349 /// `font_id_for_cosmic_id` when computing the *output* of `layout_line`.
350 fn font_id_for_cosmic_id(&mut self, id: cosmic_text::fontdb::ID) -> FontId {
351 if let Some(ix) = self
352 .loaded_fonts
353 .iter()
354 .position(|loaded_font| loaded_font.font.id() == id)
355 {
356 FontId(ix)
357 } else {
358 let font = self.font_system.get_font(id).unwrap();
359 let face = self.font_system.db().face(id).unwrap();
360
361 let font_id = FontId(self.loaded_fonts.len());
362 self.loaded_fonts.push(LoadedFont {
363 font,
364 features: CosmicFontFeatures::new(),
365 is_known_emoji_font: check_is_known_emoji_font(&face.post_script_name),
366 });
367
368 font_id
369 }
370 }
371
372 #[profiling::function]
373 fn layout_line(&mut self, text: &str, font_size: Pixels, font_runs: &[FontRun]) -> LineLayout {
374 let mut attrs_list = AttrsList::new(&Attrs::new());
375 let mut offs = 0;
376 for run in font_runs {
377 let loaded_font = self.loaded_font(run.font_id);
378 let font = self.font_system.db().face(loaded_font.font.id()).unwrap();
379
380 attrs_list.add_span(
381 offs..(offs + run.len),
382 &Attrs::new()
383 .metadata(run.font_id.0)
384 .family(Family::Name(&font.families.first().unwrap().0))
385 .stretch(font.stretch)
386 .style(font.style)
387 .weight(font.weight)
388 .font_features(loaded_font.features.clone()),
389 );
390 offs += run.len;
391 }
392
393 let line = ShapeLine::new(
394 &mut self.font_system,
395 text,
396 &attrs_list,
397 cosmic_text::Shaping::Advanced,
398 4,
399 );
400 let mut layout_lines = Vec::with_capacity(1);
401 line.layout_to_buffer(
402 &mut self.scratch,
403 font_size.0,
404 None, // We do our own wrapping
405 cosmic_text::Wrap::None,
406 None,
407 &mut layout_lines,
408 None,
409 );
410 let layout = layout_lines.first().unwrap();
411
412 let mut runs: Vec<ShapedRun> = Vec::new();
413 for glyph in &layout.glyphs {
414 let mut font_id = FontId(glyph.metadata);
415 let mut loaded_font = self.loaded_font(font_id);
416 if loaded_font.font.id() != glyph.font_id {
417 font_id = self.font_id_for_cosmic_id(glyph.font_id);
418 loaded_font = self.loaded_font(font_id);
419 }
420 let is_emoji = loaded_font.is_known_emoji_font;
421
422 // HACK: Prevent crash caused by variation selectors.
423 if glyph.glyph_id == 3 && is_emoji {
424 continue;
425 }
426
427 let shaped_glyph = ShapedGlyph {
428 id: GlyphId(glyph.glyph_id as u32),
429 position: point(glyph.x.into(), glyph.y.into()),
430 index: glyph.start,
431 is_emoji,
432 };
433
434 if let Some(last_run) = runs
435 .last_mut()
436 .filter(|last_run| last_run.font_id == font_id)
437 {
438 last_run.glyphs.push(shaped_glyph);
439 } else {
440 runs.push(ShapedRun {
441 font_id,
442 glyphs: vec![shaped_glyph],
443 });
444 }
445 }
446
447 LineLayout {
448 font_size,
449 width: layout.w.into(),
450 ascent: layout.max_ascent.into(),
451 descent: layout.max_descent.into(),
452 runs,
453 len: text.len(),
454 }
455 }
456}
457
458impl TryFrom<&FontFeatures> for CosmicFontFeatures {
459 type Error = anyhow::Error;
460
461 fn try_from(features: &FontFeatures) -> Result<Self> {
462 let mut result = CosmicFontFeatures::new();
463 for feature in features.0.iter() {
464 let name_bytes: [u8; 4] = feature
465 .0
466 .as_bytes()
467 .try_into()
468 .context("Incorrect feature flag format")?;
469
470 let tag = cosmic_text::FeatureTag::new(&name_bytes);
471
472 result.set(tag, feature.1);
473 }
474 Ok(result)
475 }
476}
477
478impl From<RectF> for Bounds<f32> {
479 fn from(rect: RectF) -> Self {
480 Bounds {
481 origin: point(rect.origin_x(), rect.origin_y()),
482 size: size(rect.width(), rect.height()),
483 }
484 }
485}
486
487impl From<RectI> for Bounds<DevicePixels> {
488 fn from(rect: RectI) -> Self {
489 Bounds {
490 origin: point(DevicePixels(rect.origin_x()), DevicePixels(rect.origin_y())),
491 size: size(DevicePixels(rect.width()), DevicePixels(rect.height())),
492 }
493 }
494}
495
496impl From<Vector2I> for Size<DevicePixels> {
497 fn from(value: Vector2I) -> Self {
498 size(value.x().into(), value.y().into())
499 }
500}
501
502impl From<RectI> for Bounds<i32> {
503 fn from(rect: RectI) -> Self {
504 Bounds {
505 origin: point(rect.origin_x(), rect.origin_y()),
506 size: size(rect.width(), rect.height()),
507 }
508 }
509}
510
511impl From<Point<u32>> for Vector2I {
512 fn from(size: Point<u32>) -> Self {
513 Vector2I::new(size.x as i32, size.y as i32)
514 }
515}
516
517impl From<Vector2F> for Size<f32> {
518 fn from(vec: Vector2F) -> Self {
519 size(vec.x(), vec.y())
520 }
521}
522
523impl From<FontWeight> for cosmic_text::Weight {
524 fn from(value: FontWeight) -> Self {
525 cosmic_text::Weight(value.0 as u16)
526 }
527}
528
529impl From<FontStyle> for cosmic_text::Style {
530 fn from(style: FontStyle) -> Self {
531 match style {
532 FontStyle::Normal => cosmic_text::Style::Normal,
533 FontStyle::Italic => cosmic_text::Style::Italic,
534 FontStyle::Oblique => cosmic_text::Style::Oblique,
535 }
536 }
537}
538
539fn font_into_properties(font: &crate::Font) -> font_kit::properties::Properties {
540 font_kit::properties::Properties {
541 style: match font.style {
542 crate::FontStyle::Normal => font_kit::properties::Style::Normal,
543 crate::FontStyle::Italic => font_kit::properties::Style::Italic,
544 crate::FontStyle::Oblique => font_kit::properties::Style::Oblique,
545 },
546 weight: font_kit::properties::Weight(font.weight.0),
547 stretch: Default::default(),
548 }
549}
550
551fn face_info_into_properties(
552 face_info: &cosmic_text::fontdb::FaceInfo,
553) -> font_kit::properties::Properties {
554 font_kit::properties::Properties {
555 style: match face_info.style {
556 cosmic_text::Style::Normal => font_kit::properties::Style::Normal,
557 cosmic_text::Style::Italic => font_kit::properties::Style::Italic,
558 cosmic_text::Style::Oblique => font_kit::properties::Style::Oblique,
559 },
560 // both libs use the same values for weight
561 weight: font_kit::properties::Weight(face_info.weight.0.into()),
562 stretch: match face_info.stretch {
563 cosmic_text::Stretch::Condensed => font_kit::properties::Stretch::CONDENSED,
564 cosmic_text::Stretch::Expanded => font_kit::properties::Stretch::EXPANDED,
565 cosmic_text::Stretch::ExtraCondensed => font_kit::properties::Stretch::EXTRA_CONDENSED,
566 cosmic_text::Stretch::ExtraExpanded => font_kit::properties::Stretch::EXTRA_EXPANDED,
567 cosmic_text::Stretch::Normal => font_kit::properties::Stretch::NORMAL,
568 cosmic_text::Stretch::SemiCondensed => font_kit::properties::Stretch::SEMI_CONDENSED,
569 cosmic_text::Stretch::SemiExpanded => font_kit::properties::Stretch::SEMI_EXPANDED,
570 cosmic_text::Stretch::UltraCondensed => font_kit::properties::Stretch::ULTRA_CONDENSED,
571 cosmic_text::Stretch::UltraExpanded => font_kit::properties::Stretch::ULTRA_EXPANDED,
572 },
573 }
574}
575
576fn check_is_known_emoji_font(postscript_name: &str) -> bool {
577 // TODO: Include other common emoji fonts
578 postscript_name == "NotoColorEmoji"
579}