1mod font_fallbacks;
2mod font_features;
3mod line;
4mod line_layout;
5mod line_wrapper;
6
7pub use font_fallbacks::*;
8pub use font_features::*;
9pub use line::*;
10pub use line_layout::*;
11pub use line_wrapper::*;
12use schemars::JsonSchema;
13use serde::{Deserialize, Serialize};
14
15use crate::{
16 Bounds, DevicePixels, Hsla, Pixels, PlatformTextSystem, Point, Result, SharedString, Size,
17 StrikethroughStyle, UnderlineStyle, px,
18};
19use anyhow::{Context as _, anyhow};
20use collections::FxHashMap;
21use core::fmt;
22use derive_more::Deref;
23use itertools::Itertools;
24use parking_lot::{Mutex, RwLock, RwLockUpgradableReadGuard};
25use smallvec::{SmallVec, smallvec};
26use std::{
27 borrow::Cow,
28 cmp,
29 fmt::{Debug, Display, Formatter},
30 hash::{Hash, Hasher},
31 ops::{Deref, DerefMut, Range},
32 sync::Arc,
33};
34
35/// An opaque identifier for a specific font.
36#[derive(Hash, PartialEq, Eq, Clone, Copy, Debug)]
37#[repr(C)]
38pub struct FontId(pub usize);
39
40/// An opaque identifier for a specific font family.
41#[derive(Hash, PartialEq, Eq, Clone, Copy, Debug)]
42pub struct FontFamilyId(pub usize);
43
44pub(crate) const SUBPIXEL_VARIANTS_X: u8 = 4;
45
46pub(crate) const SUBPIXEL_VARIANTS_Y: u8 =
47 if cfg!(target_os = "windows") || cfg!(target_os = "linux") {
48 1
49 } else {
50 SUBPIXEL_VARIANTS_X
51 };
52
53/// The GPUI text rendering sub system.
54pub struct TextSystem {
55 platform_text_system: Arc<dyn PlatformTextSystem>,
56 font_ids_by_font: RwLock<FxHashMap<Font, Result<FontId>>>,
57 font_metrics: RwLock<FxHashMap<FontId, FontMetrics>>,
58 raster_bounds: RwLock<FxHashMap<RenderGlyphParams, Bounds<DevicePixels>>>,
59 wrapper_pool: Mutex<FxHashMap<FontIdWithSize, Vec<LineWrapper>>>,
60 font_runs_pool: Mutex<Vec<Vec<FontRun>>>,
61 fallback_font_stack: SmallVec<[Font; 2]>,
62}
63
64impl TextSystem {
65 pub(crate) fn new(platform_text_system: Arc<dyn PlatformTextSystem>) -> Self {
66 TextSystem {
67 platform_text_system,
68 font_metrics: RwLock::default(),
69 raster_bounds: RwLock::default(),
70 font_ids_by_font: RwLock::default(),
71 wrapper_pool: Mutex::default(),
72 font_runs_pool: Mutex::default(),
73 fallback_font_stack: smallvec![
74 // TODO: Remove this when Linux have implemented setting fallbacks.
75 font(".ZedMono"),
76 font("Helvetica"),
77 font("Segoe UI"), // Windows
78 font("Cantarell"), // Gnome
79 font("Ubuntu"), // Gnome (Ubuntu)
80 font("Noto Sans"), // KDE
81 font("DejaVu Sans")
82 ],
83 }
84 }
85
86 /// Get a list of all available font names from the operating system.
87 pub fn all_font_names(&self) -> Vec<String> {
88 let mut names = self.platform_text_system.all_font_names();
89 names.extend(
90 self.fallback_font_stack
91 .iter()
92 .map(|font| font.family.to_string()),
93 );
94 names.push(".SystemUIFont".to_string());
95 names.sort();
96 names.dedup();
97 names
98 }
99
100 /// Add a font's data to the text system.
101 pub fn add_fonts(&self, fonts: Vec<Cow<'static, [u8]>>) -> Result<()> {
102 self.platform_text_system.add_fonts(fonts)
103 }
104
105 /// Get the FontId for the configure font family and style.
106 fn font_id(&self, font: &Font) -> Result<FontId> {
107 fn clone_font_id_result(font_id: &Result<FontId>) -> Result<FontId> {
108 match font_id {
109 Ok(font_id) => Ok(*font_id),
110 Err(err) => Err(anyhow!("{err}")),
111 }
112 }
113
114 let font_id = self
115 .font_ids_by_font
116 .read()
117 .get(font)
118 .map(clone_font_id_result);
119 if let Some(font_id) = font_id {
120 font_id
121 } else {
122 let font_id = self.platform_text_system.font_id(font);
123 self.font_ids_by_font
124 .write()
125 .insert(font.clone(), clone_font_id_result(&font_id));
126 font_id
127 }
128 }
129
130 /// Get the Font for the Font Id.
131 pub fn get_font_for_id(&self, id: FontId) -> Option<Font> {
132 let lock = self.font_ids_by_font.read();
133 lock.iter()
134 .filter_map(|(font, result)| match result {
135 Ok(font_id) if *font_id == id => Some(font.clone()),
136 _ => None,
137 })
138 .next()
139 }
140
141 /// Resolves the specified font, falling back to the default font stack if
142 /// the font fails to load.
143 ///
144 /// # Panics
145 ///
146 /// Panics if the font and none of the fallbacks can be resolved.
147 pub fn resolve_font(&self, font: &Font) -> FontId {
148 if let Ok(font_id) = self.font_id(font) {
149 return font_id;
150 }
151 for fallback in &self.fallback_font_stack {
152 if let Ok(font_id) = self.font_id(fallback) {
153 return font_id;
154 }
155 }
156
157 panic!(
158 "failed to resolve font '{}' or any of the fallbacks: {}",
159 font.family,
160 self.fallback_font_stack
161 .iter()
162 .map(|fallback| &fallback.family)
163 .join(", ")
164 );
165 }
166
167 /// Get the bounding box for the given font and font size.
168 /// A font's bounding box is the smallest rectangle that could enclose all glyphs
169 /// in the font. superimposed over one another.
170 pub fn bounding_box(&self, font_id: FontId, font_size: Pixels) -> Bounds<Pixels> {
171 self.read_metrics(font_id, |metrics| metrics.bounding_box(font_size))
172 }
173
174 /// Get the typographic bounds for the given character, in the given font and size.
175 pub fn typographic_bounds(
176 &self,
177 font_id: FontId,
178 font_size: Pixels,
179 character: char,
180 ) -> Result<Bounds<Pixels>> {
181 let glyph_id = self
182 .platform_text_system
183 .glyph_for_char(font_id, character)
184 .with_context(|| format!("glyph not found for character '{character}'"))?;
185 let bounds = self
186 .platform_text_system
187 .typographic_bounds(font_id, glyph_id)?;
188 Ok(self.read_metrics(font_id, |metrics| {
189 (bounds / metrics.units_per_em as f32 * font_size.0).map(px)
190 }))
191 }
192
193 /// Get the advance width for the given character, in the given font and size.
194 pub fn advance(&self, font_id: FontId, font_size: Pixels, ch: char) -> Result<Size<Pixels>> {
195 let glyph_id = self
196 .platform_text_system
197 .glyph_for_char(font_id, ch)
198 .with_context(|| format!("glyph not found for character '{ch}'"))?;
199 let result = self.platform_text_system.advance(font_id, glyph_id)?
200 / self.units_per_em(font_id) as f32;
201
202 Ok(result * font_size)
203 }
204
205 /// Returns the width of an `em`.
206 ///
207 /// Uses the width of the `m` character in the given font and size.
208 pub fn em_width(&self, font_id: FontId, font_size: Pixels) -> Result<Pixels> {
209 Ok(self.typographic_bounds(font_id, font_size, 'm')?.size.width)
210 }
211
212 /// Returns the advance width of an `em`.
213 ///
214 /// Uses the advance width of the `m` character in the given font and size.
215 pub fn em_advance(&self, font_id: FontId, font_size: Pixels) -> Result<Pixels> {
216 Ok(self.advance(font_id, font_size, 'm')?.width)
217 }
218
219 /// Returns the width of an `ch`.
220 ///
221 /// Uses the width of the `0` character in the given font and size.
222 pub fn ch_width(&self, font_id: FontId, font_size: Pixels) -> Result<Pixels> {
223 Ok(self.typographic_bounds(font_id, font_size, '0')?.size.width)
224 }
225
226 /// Returns the advance width of an `ch`.
227 ///
228 /// Uses the advance width of the `0` character in the given font and size.
229 pub fn ch_advance(&self, font_id: FontId, font_size: Pixels) -> Result<Pixels> {
230 Ok(self.advance(font_id, font_size, '0')?.width)
231 }
232
233 /// Get the number of font size units per 'em square',
234 /// Per MDN: "an abstract square whose height is the intended distance between
235 /// lines of type in the same type size"
236 pub fn units_per_em(&self, font_id: FontId) -> u32 {
237 self.read_metrics(font_id, |metrics| metrics.units_per_em)
238 }
239
240 /// Get the height of a capital letter in the given font and size.
241 pub fn cap_height(&self, font_id: FontId, font_size: Pixels) -> Pixels {
242 self.read_metrics(font_id, |metrics| metrics.cap_height(font_size))
243 }
244
245 /// Get the height of the x character in the given font and size.
246 pub fn x_height(&self, font_id: FontId, font_size: Pixels) -> Pixels {
247 self.read_metrics(font_id, |metrics| metrics.x_height(font_size))
248 }
249
250 /// Get the recommended distance from the baseline for the given font
251 pub fn ascent(&self, font_id: FontId, font_size: Pixels) -> Pixels {
252 self.read_metrics(font_id, |metrics| metrics.ascent(font_size))
253 }
254
255 /// Get the recommended distance below the baseline for the given font,
256 /// in single spaced text.
257 pub fn descent(&self, font_id: FontId, font_size: Pixels) -> Pixels {
258 self.read_metrics(font_id, |metrics| metrics.descent(font_size))
259 }
260
261 /// Get the recommended baseline offset for the given font and line height.
262 pub fn baseline_offset(
263 &self,
264 font_id: FontId,
265 font_size: Pixels,
266 line_height: Pixels,
267 ) -> Pixels {
268 let ascent = self.ascent(font_id, font_size);
269 let descent = self.descent(font_id, font_size);
270 let padding_top = (line_height - ascent - descent) / 2.;
271 padding_top + ascent
272 }
273
274 fn read_metrics<T>(&self, font_id: FontId, read: impl FnOnce(&FontMetrics) -> T) -> T {
275 let lock = self.font_metrics.upgradable_read();
276
277 if let Some(metrics) = lock.get(&font_id) {
278 read(metrics)
279 } else {
280 let mut lock = RwLockUpgradableReadGuard::upgrade(lock);
281 let metrics = lock
282 .entry(font_id)
283 .or_insert_with(|| self.platform_text_system.font_metrics(font_id));
284 read(metrics)
285 }
286 }
287
288 /// Returns a handle to a line wrapper, for the given font and font size.
289 pub fn line_wrapper(self: &Arc<Self>, font: Font, font_size: Pixels) -> LineWrapperHandle {
290 let lock = &mut self.wrapper_pool.lock();
291 let font_id = self.resolve_font(&font);
292 let wrappers = lock
293 .entry(FontIdWithSize { font_id, font_size })
294 .or_default();
295 let wrapper = wrappers.pop().unwrap_or_else(|| {
296 LineWrapper::new(font_id, font_size, self.platform_text_system.clone())
297 });
298
299 LineWrapperHandle {
300 wrapper: Some(wrapper),
301 text_system: self.clone(),
302 }
303 }
304
305 /// Get the rasterized size and location of a specific, rendered glyph.
306 pub(crate) fn raster_bounds(&self, params: &RenderGlyphParams) -> Result<Bounds<DevicePixels>> {
307 let raster_bounds = self.raster_bounds.upgradable_read();
308 if let Some(bounds) = raster_bounds.get(params) {
309 Ok(*bounds)
310 } else {
311 let mut raster_bounds = RwLockUpgradableReadGuard::upgrade(raster_bounds);
312 let bounds = self.platform_text_system.glyph_raster_bounds(params)?;
313 raster_bounds.insert(params.clone(), bounds);
314 Ok(bounds)
315 }
316 }
317
318 pub(crate) fn rasterize_glyph(
319 &self,
320 params: &RenderGlyphParams,
321 ) -> Result<(Size<DevicePixels>, Vec<u8>)> {
322 let raster_bounds = self.raster_bounds(params)?;
323 self.platform_text_system
324 .rasterize_glyph(params, raster_bounds)
325 }
326}
327
328/// The GPUI text layout subsystem.
329#[derive(Deref)]
330pub struct WindowTextSystem {
331 line_layout_cache: LineLayoutCache,
332 #[deref]
333 text_system: Arc<TextSystem>,
334}
335
336impl WindowTextSystem {
337 pub(crate) fn new(text_system: Arc<TextSystem>) -> Self {
338 Self {
339 line_layout_cache: LineLayoutCache::new(text_system.platform_text_system.clone()),
340 text_system,
341 }
342 }
343
344 pub(crate) fn layout_index(&self) -> LineLayoutIndex {
345 self.line_layout_cache.layout_index()
346 }
347
348 pub(crate) fn reuse_layouts(&self, index: Range<LineLayoutIndex>) {
349 self.line_layout_cache.reuse_layouts(index)
350 }
351
352 pub(crate) fn truncate_layouts(&self, index: LineLayoutIndex) {
353 self.line_layout_cache.truncate_layouts(index)
354 }
355
356 /// Shape the given line, at the given font_size, for painting to the screen.
357 /// Subsets of the line can be styled independently with the `runs` parameter.
358 ///
359 /// Note that this method can only shape a single line of text. It will panic
360 /// if the text contains newlines. If you need to shape multiple lines of text,
361 /// use [`Self::shape_text`] instead.
362 pub fn shape_line(
363 &self,
364 text: SharedString,
365 font_size: Pixels,
366 runs: &[TextRun],
367 force_width: Option<Pixels>,
368 ) -> ShapedLine {
369 debug_assert!(
370 text.find('\n').is_none(),
371 "text argument should not contain newlines"
372 );
373
374 let mut decoration_runs = SmallVec::<[DecorationRun; 32]>::new();
375 for run in runs {
376 if let Some(last_run) = decoration_runs.last_mut()
377 && last_run.color == run.color
378 && last_run.underline == run.underline
379 && last_run.strikethrough == run.strikethrough
380 && last_run.background_color == run.background_color
381 {
382 last_run.len += run.len as u32;
383 continue;
384 }
385 decoration_runs.push(DecorationRun {
386 len: run.len as u32,
387 color: run.color,
388 background_color: run.background_color,
389 underline: run.underline,
390 strikethrough: run.strikethrough,
391 });
392 }
393
394 let layout = self.layout_line(&text, font_size, runs, force_width);
395
396 ShapedLine {
397 layout,
398 text,
399 decoration_runs,
400 }
401 }
402
403 /// Shape a multi line string of text, at the given font_size, for painting to the screen.
404 /// Subsets of the text can be styled independently with the `runs` parameter.
405 /// If `wrap_width` is provided, the line breaks will be adjusted to fit within the given width.
406 pub fn shape_text(
407 &self,
408 text: SharedString,
409 font_size: Pixels,
410 runs: &[TextRun],
411 wrap_width: Option<Pixels>,
412 line_clamp: Option<usize>,
413 ) -> Result<SmallVec<[WrappedLine; 1]>> {
414 let mut runs = runs.iter().filter(|run| run.len > 0).cloned().peekable();
415 let mut font_runs = self.font_runs_pool.lock().pop().unwrap_or_default();
416
417 let mut lines = SmallVec::new();
418 let mut line_start = 0;
419 let mut max_wrap_lines = line_clamp.unwrap_or(usize::MAX);
420 let mut wrapped_lines = 0;
421
422 let mut process_line = |line_text: SharedString| {
423 let line_end = line_start + line_text.len();
424
425 let mut last_font: Option<Font> = None;
426 let mut decoration_runs = SmallVec::<[DecorationRun; 32]>::new();
427 let mut run_start = line_start;
428 while run_start < line_end {
429 let Some(run) = runs.peek_mut() else {
430 break;
431 };
432
433 let run_len_within_line = cmp::min(line_end, run_start + run.len) - run_start;
434
435 if last_font == Some(run.font.clone()) {
436 font_runs.last_mut().unwrap().len += run_len_within_line;
437 } else {
438 last_font = Some(run.font.clone());
439 font_runs.push(FontRun {
440 len: run_len_within_line,
441 font_id: self.resolve_font(&run.font),
442 });
443 }
444
445 if decoration_runs.last().is_some_and(|last_run| {
446 last_run.color == run.color
447 && last_run.underline == run.underline
448 && last_run.strikethrough == run.strikethrough
449 && last_run.background_color == run.background_color
450 }) {
451 decoration_runs.last_mut().unwrap().len += run_len_within_line as u32;
452 } else {
453 decoration_runs.push(DecorationRun {
454 len: run_len_within_line as u32,
455 color: run.color,
456 background_color: run.background_color,
457 underline: run.underline,
458 strikethrough: run.strikethrough,
459 });
460 }
461
462 if run_len_within_line == run.len {
463 runs.next();
464 } else {
465 // Preserve the remainder of the run for the next line
466 run.len -= run_len_within_line;
467 }
468 run_start += run_len_within_line;
469 }
470
471 let layout = self.line_layout_cache.layout_wrapped_line(
472 &line_text,
473 font_size,
474 &font_runs,
475 wrap_width,
476 Some(max_wrap_lines - wrapped_lines),
477 );
478 wrapped_lines += layout.wrap_boundaries.len();
479
480 lines.push(WrappedLine {
481 layout,
482 decoration_runs,
483 text: line_text,
484 });
485
486 // Skip `\n` character.
487 line_start = line_end + 1;
488 if let Some(run) = runs.peek_mut() {
489 run.len -= 1;
490 if run.len == 0 {
491 runs.next();
492 }
493 }
494
495 font_runs.clear();
496 };
497
498 let mut split_lines = text.split('\n');
499 let mut processed = false;
500
501 if let Some(first_line) = split_lines.next()
502 && let Some(second_line) = split_lines.next()
503 {
504 processed = true;
505 process_line(first_line.to_string().into());
506 process_line(second_line.to_string().into());
507 for line_text in split_lines {
508 process_line(line_text.to_string().into());
509 }
510 }
511
512 if !processed {
513 process_line(text);
514 }
515
516 self.font_runs_pool.lock().push(font_runs);
517
518 Ok(lines)
519 }
520
521 pub(crate) fn finish_frame(&self) {
522 self.line_layout_cache.finish_frame()
523 }
524
525 /// Layout the given line of text, at the given font_size.
526 /// Subsets of the line can be styled independently with the `runs` parameter.
527 /// Generally, you should prefer to use [`Self::shape_line`] instead, which
528 /// can be painted directly.
529 pub fn layout_line<Text>(
530 &self,
531 text: Text,
532 font_size: Pixels,
533 runs: &[TextRun],
534 force_width: Option<Pixels>,
535 ) -> Arc<LineLayout>
536 where
537 Text: AsRef<str>,
538 SharedString: From<Text>,
539 {
540 let mut font_runs = self.font_runs_pool.lock().pop().unwrap_or_default();
541 for run in runs.iter() {
542 let font_id = self.resolve_font(&run.font);
543 if let Some(last_run) = font_runs.last_mut()
544 && last_run.font_id == font_id
545 {
546 last_run.len += run.len;
547 continue;
548 }
549 font_runs.push(FontRun {
550 len: run.len,
551 font_id,
552 });
553 }
554
555 let layout =
556 self.line_layout_cache
557 .layout_line_internal(text, font_size, &font_runs, force_width);
558
559 font_runs.clear();
560 self.font_runs_pool.lock().push(font_runs);
561
562 layout
563 }
564}
565
566#[derive(Hash, Eq, PartialEq)]
567struct FontIdWithSize {
568 font_id: FontId,
569 font_size: Pixels,
570}
571
572/// A handle into the text system, which can be used to compute the wrapped layout of text
573pub struct LineWrapperHandle {
574 wrapper: Option<LineWrapper>,
575 text_system: Arc<TextSystem>,
576}
577
578impl Drop for LineWrapperHandle {
579 fn drop(&mut self) {
580 let mut state = self.text_system.wrapper_pool.lock();
581 let wrapper = self.wrapper.take().unwrap();
582 state
583 .get_mut(&FontIdWithSize {
584 font_id: wrapper.font_id,
585 font_size: wrapper.font_size,
586 })
587 .unwrap()
588 .push(wrapper);
589 }
590}
591
592impl Deref for LineWrapperHandle {
593 type Target = LineWrapper;
594
595 fn deref(&self) -> &Self::Target {
596 self.wrapper.as_ref().unwrap()
597 }
598}
599
600impl DerefMut for LineWrapperHandle {
601 fn deref_mut(&mut self) -> &mut Self::Target {
602 self.wrapper.as_mut().unwrap()
603 }
604}
605
606/// The degree of blackness or stroke thickness of a font. This value ranges from 100.0 to 900.0,
607/// with 400.0 as normal.
608#[derive(Clone, Copy, Debug, PartialEq, PartialOrd, Serialize, Deserialize, JsonSchema)]
609pub struct FontWeight(pub f32);
610
611impl Default for FontWeight {
612 #[inline]
613 fn default() -> FontWeight {
614 FontWeight::NORMAL
615 }
616}
617
618impl Hash for FontWeight {
619 fn hash<H: Hasher>(&self, state: &mut H) {
620 state.write_u32(u32::from_be_bytes(self.0.to_be_bytes()));
621 }
622}
623
624impl Eq for FontWeight {}
625
626impl FontWeight {
627 /// Thin weight (100), the thinnest value.
628 pub const THIN: FontWeight = FontWeight(100.0);
629 /// Extra light weight (200).
630 pub const EXTRA_LIGHT: FontWeight = FontWeight(200.0);
631 /// Light weight (300).
632 pub const LIGHT: FontWeight = FontWeight(300.0);
633 /// Normal (400).
634 pub const NORMAL: FontWeight = FontWeight(400.0);
635 /// Medium weight (500, higher than normal).
636 pub const MEDIUM: FontWeight = FontWeight(500.0);
637 /// Semibold weight (600).
638 pub const SEMIBOLD: FontWeight = FontWeight(600.0);
639 /// Bold weight (700).
640 pub const BOLD: FontWeight = FontWeight(700.0);
641 /// Extra-bold weight (800).
642 pub const EXTRA_BOLD: FontWeight = FontWeight(800.0);
643 /// Black weight (900), the thickest value.
644 pub const BLACK: FontWeight = FontWeight(900.0);
645
646 /// All of the font weights, in order from thinnest to thickest.
647 pub const ALL: [FontWeight; 9] = [
648 Self::THIN,
649 Self::EXTRA_LIGHT,
650 Self::LIGHT,
651 Self::NORMAL,
652 Self::MEDIUM,
653 Self::SEMIBOLD,
654 Self::BOLD,
655 Self::EXTRA_BOLD,
656 Self::BLACK,
657 ];
658}
659
660/// Allows italic or oblique faces to be selected.
661#[derive(Clone, Copy, Eq, PartialEq, Debug, Hash, Default, Serialize, Deserialize, JsonSchema)]
662pub enum FontStyle {
663 /// A face that is neither italic not obliqued.
664 #[default]
665 Normal,
666 /// A form that is generally cursive in nature.
667 Italic,
668 /// A typically-sloped version of the regular face.
669 Oblique,
670}
671
672impl Display for FontStyle {
673 fn fmt(&self, f: &mut Formatter) -> fmt::Result {
674 Debug::fmt(self, f)
675 }
676}
677
678/// A styled run of text, for use in [`crate::TextLayout`].
679#[derive(Clone, Debug, PartialEq, Eq)]
680pub struct TextRun {
681 /// A number of utf8 bytes
682 pub len: usize,
683 /// The font to use for this run.
684 pub font: Font,
685 /// The color
686 pub color: Hsla,
687 /// The background color (if any)
688 pub background_color: Option<Hsla>,
689 /// The underline style (if any)
690 pub underline: Option<UnderlineStyle>,
691 /// The strikethrough style (if any)
692 pub strikethrough: Option<StrikethroughStyle>,
693}
694
695#[cfg(all(target_os = "macos", test))]
696impl TextRun {
697 fn with_len(&self, len: usize) -> Self {
698 let mut this = self.clone();
699 this.len = len;
700 this
701 }
702}
703
704/// An identifier for a specific glyph, as returned by [`WindowTextSystem::layout_line`].
705#[derive(Copy, Clone, Debug, Eq, PartialEq, Hash)]
706#[repr(C)]
707pub struct GlyphId(pub(crate) u32);
708
709#[derive(Clone, Debug, PartialEq)]
710pub(crate) struct RenderGlyphParams {
711 pub(crate) font_id: FontId,
712 pub(crate) glyph_id: GlyphId,
713 pub(crate) font_size: Pixels,
714 pub(crate) subpixel_variant: Point<u8>,
715 pub(crate) scale_factor: f32,
716 pub(crate) is_emoji: bool,
717}
718
719impl Eq for RenderGlyphParams {}
720
721impl Hash for RenderGlyphParams {
722 fn hash<H: Hasher>(&self, state: &mut H) {
723 self.font_id.0.hash(state);
724 self.glyph_id.0.hash(state);
725 self.font_size.0.to_bits().hash(state);
726 self.subpixel_variant.hash(state);
727 self.scale_factor.to_bits().hash(state);
728 self.is_emoji.hash(state);
729 }
730}
731
732/// The configuration details for identifying a specific font.
733#[derive(Clone, Debug, Eq, PartialEq, Hash)]
734pub struct Font {
735 /// The font family name.
736 ///
737 /// The special name ".SystemUIFont" is used to identify the system UI font, which varies based on platform.
738 pub family: SharedString,
739
740 /// The font features to use.
741 pub features: FontFeatures,
742
743 /// The fallbacks fonts to use.
744 pub fallbacks: Option<FontFallbacks>,
745
746 /// The font weight.
747 pub weight: FontWeight,
748
749 /// The font style.
750 pub style: FontStyle,
751}
752
753/// Get a [`Font`] for a given name.
754pub fn font(family: impl Into<SharedString>) -> Font {
755 Font {
756 family: family.into(),
757 features: FontFeatures::default(),
758 weight: FontWeight::default(),
759 style: FontStyle::default(),
760 fallbacks: None,
761 }
762}
763
764impl Font {
765 /// Set this Font to be bold
766 pub fn bold(mut self) -> Self {
767 self.weight = FontWeight::BOLD;
768 self
769 }
770
771 /// Set this Font to be italic
772 pub fn italic(mut self) -> Self {
773 self.style = FontStyle::Italic;
774 self
775 }
776}
777
778/// A struct for storing font metrics.
779/// It is used to define the measurements of a typeface.
780#[derive(Clone, Copy, Debug)]
781pub struct FontMetrics {
782 /// The number of font units that make up the "em square",
783 /// a scalable grid for determining the size of a typeface.
784 pub(crate) units_per_em: u32,
785
786 /// The vertical distance from the baseline of the font to the top of the glyph covers.
787 pub(crate) ascent: f32,
788
789 /// The vertical distance from the baseline of the font to the bottom of the glyph covers.
790 pub(crate) descent: f32,
791
792 /// The recommended additional space to add between lines of type.
793 pub(crate) line_gap: f32,
794
795 /// The suggested position of the underline.
796 pub(crate) underline_position: f32,
797
798 /// The suggested thickness of the underline.
799 pub(crate) underline_thickness: f32,
800
801 /// The height of a capital letter measured from the baseline of the font.
802 pub(crate) cap_height: f32,
803
804 /// The height of a lowercase x.
805 pub(crate) x_height: f32,
806
807 /// The outer limits of the area that the font covers.
808 /// Corresponds to the xMin / xMax / yMin / yMax values in the OpenType `head` table
809 pub(crate) bounding_box: Bounds<f32>,
810}
811
812impl FontMetrics {
813 /// Returns the vertical distance from the baseline of the font to the top of the glyph covers in pixels.
814 pub fn ascent(&self, font_size: Pixels) -> Pixels {
815 Pixels((self.ascent / self.units_per_em as f32) * font_size.0)
816 }
817
818 /// Returns the vertical distance from the baseline of the font to the bottom of the glyph covers in pixels.
819 pub fn descent(&self, font_size: Pixels) -> Pixels {
820 Pixels((self.descent / self.units_per_em as f32) * font_size.0)
821 }
822
823 /// Returns the recommended additional space to add between lines of type in pixels.
824 pub fn line_gap(&self, font_size: Pixels) -> Pixels {
825 Pixels((self.line_gap / self.units_per_em as f32) * font_size.0)
826 }
827
828 /// Returns the suggested position of the underline in pixels.
829 pub fn underline_position(&self, font_size: Pixels) -> Pixels {
830 Pixels((self.underline_position / self.units_per_em as f32) * font_size.0)
831 }
832
833 /// Returns the suggested thickness of the underline in pixels.
834 pub fn underline_thickness(&self, font_size: Pixels) -> Pixels {
835 Pixels((self.underline_thickness / self.units_per_em as f32) * font_size.0)
836 }
837
838 /// Returns the height of a capital letter measured from the baseline of the font in pixels.
839 pub fn cap_height(&self, font_size: Pixels) -> Pixels {
840 Pixels((self.cap_height / self.units_per_em as f32) * font_size.0)
841 }
842
843 /// Returns the height of a lowercase x in pixels.
844 pub fn x_height(&self, font_size: Pixels) -> Pixels {
845 Pixels((self.x_height / self.units_per_em as f32) * font_size.0)
846 }
847
848 /// Returns the outer limits of the area that the font covers in pixels.
849 pub fn bounding_box(&self, font_size: Pixels) -> Bounds<Pixels> {
850 (self.bounding_box / self.units_per_em as f32 * font_size.0).map(px)
851 }
852}
853
854#[allow(unused)]
855pub(crate) fn font_name_with_fallbacks<'a>(name: &'a str, system: &'a str) -> &'a str {
856 // Note: the "Zed Plex" fonts were deprecated as we are not allowed to use "Plex"
857 // in a derived font name. They are essentially indistinguishable from IBM Plex/Lilex,
858 // and so retained here for backward compatibility.
859 match name {
860 ".SystemUIFont" => system,
861 ".ZedSans" | "Zed Plex Sans" => "IBM Plex Sans",
862 ".ZedMono" | "Zed Plex Mono" => "Lilex",
863 _ => name,
864 }
865}