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::{Add, Deref, FromStr, Sub};
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(".ZedSans"),
77 font("Helvetica"),
78 font("Segoe UI"), // Windows
79 font("Ubuntu"), // Gnome (Ubuntu)
80 font("Adwaita Sans"), // Gnome 47
81 font("Cantarell"), // Gnome
82 font("Noto Sans"), // KDE
83 font("DejaVu Sans"),
84 font("Arial"), // macOS, Windows
85 ],
86 }
87 }
88
89 /// Get a list of all available font names from the operating system.
90 pub fn all_font_names(&self) -> Vec<String> {
91 let mut names = self.platform_text_system.all_font_names();
92 names.extend(
93 self.fallback_font_stack
94 .iter()
95 .map(|font| font.family.to_string()),
96 );
97 names.push(".SystemUIFont".to_string());
98 names.sort();
99 names.dedup();
100 names
101 }
102
103 /// Add a font's data to the text system.
104 pub fn add_fonts(&self, fonts: Vec<Cow<'static, [u8]>>) -> Result<()> {
105 self.platform_text_system.add_fonts(fonts)
106 }
107
108 /// Get the FontId for the configure font family and style.
109 fn font_id(&self, font: &Font) -> Result<FontId> {
110 fn clone_font_id_result(font_id: &Result<FontId>) -> Result<FontId> {
111 match font_id {
112 Ok(font_id) => Ok(*font_id),
113 Err(err) => Err(anyhow!("{err}")),
114 }
115 }
116
117 let font_id = self
118 .font_ids_by_font
119 .read()
120 .get(font)
121 .map(clone_font_id_result);
122 if let Some(font_id) = font_id {
123 font_id
124 } else {
125 let font_id = self.platform_text_system.font_id(font);
126 self.font_ids_by_font
127 .write()
128 .insert(font.clone(), clone_font_id_result(&font_id));
129 font_id
130 }
131 }
132
133 /// Get the Font for the Font Id.
134 pub fn get_font_for_id(&self, id: FontId) -> Option<Font> {
135 let lock = self.font_ids_by_font.read();
136 lock.iter()
137 .filter_map(|(font, result)| match result {
138 Ok(font_id) if *font_id == id => Some(font.clone()),
139 _ => None,
140 })
141 .next()
142 }
143
144 /// Resolves the specified font, falling back to the default font stack if
145 /// the font fails to load.
146 ///
147 /// # Panics
148 ///
149 /// Panics if the font and none of the fallbacks can be resolved.
150 pub fn resolve_font(&self, font: &Font) -> FontId {
151 if let Ok(font_id) = self.font_id(font) {
152 return font_id;
153 }
154 for fallback in &self.fallback_font_stack {
155 if let Ok(font_id) = self.font_id(fallback) {
156 return font_id;
157 }
158 }
159
160 panic!(
161 "failed to resolve font '{}' or any of the fallbacks: {}",
162 font.family,
163 self.fallback_font_stack
164 .iter()
165 .map(|fallback| &fallback.family)
166 .join(", ")
167 );
168 }
169
170 /// Get the bounding box for the given font and font size.
171 /// A font's bounding box is the smallest rectangle that could enclose all glyphs
172 /// in the font. superimposed over one another.
173 pub fn bounding_box(&self, font_id: FontId, font_size: Pixels) -> Bounds<Pixels> {
174 self.read_metrics(font_id, |metrics| metrics.bounding_box(font_size))
175 }
176
177 /// Get the typographic bounds for the given character, in the given font and size.
178 pub fn typographic_bounds(
179 &self,
180 font_id: FontId,
181 font_size: Pixels,
182 character: char,
183 ) -> Result<Bounds<Pixels>> {
184 let glyph_id = self
185 .platform_text_system
186 .glyph_for_char(font_id, character)
187 .with_context(|| format!("glyph not found for character '{character}'"))?;
188 let bounds = self
189 .platform_text_system
190 .typographic_bounds(font_id, glyph_id)?;
191 Ok(self.read_metrics(font_id, |metrics| {
192 (bounds / metrics.units_per_em as f32 * font_size.0).map(px)
193 }))
194 }
195
196 /// Get the advance width for the given character, in the given font and size.
197 pub fn advance(&self, font_id: FontId, font_size: Pixels, ch: char) -> Result<Size<Pixels>> {
198 let glyph_id = self
199 .platform_text_system
200 .glyph_for_char(font_id, ch)
201 .with_context(|| format!("glyph not found for character '{ch}'"))?;
202 let result = self.platform_text_system.advance(font_id, glyph_id)?
203 / self.units_per_em(font_id) as f32;
204
205 Ok(result * font_size)
206 }
207
208 /// Returns the width of an `em`.
209 ///
210 /// Uses the width of the `m` character in the given font and size.
211 pub fn em_width(&self, font_id: FontId, font_size: Pixels) -> Result<Pixels> {
212 Ok(self.typographic_bounds(font_id, font_size, 'm')?.size.width)
213 }
214
215 /// Returns the advance width of an `em`.
216 ///
217 /// Uses the advance width of the `m` character in the given font and size.
218 pub fn em_advance(&self, font_id: FontId, font_size: Pixels) -> Result<Pixels> {
219 Ok(self.advance(font_id, font_size, 'm')?.width)
220 }
221
222 /// Returns the width of an `ch`.
223 ///
224 /// Uses the width of the `0` character in the given font and size.
225 pub fn ch_width(&self, font_id: FontId, font_size: Pixels) -> Result<Pixels> {
226 Ok(self.typographic_bounds(font_id, font_size, '0')?.size.width)
227 }
228
229 /// Returns the advance width of an `ch`.
230 ///
231 /// Uses the advance width of the `0` character in the given font and size.
232 pub fn ch_advance(&self, font_id: FontId, font_size: Pixels) -> Result<Pixels> {
233 Ok(self.advance(font_id, font_size, '0')?.width)
234 }
235
236 /// Get the number of font size units per 'em square',
237 /// Per MDN: "an abstract square whose height is the intended distance between
238 /// lines of type in the same type size"
239 pub fn units_per_em(&self, font_id: FontId) -> u32 {
240 self.read_metrics(font_id, |metrics| metrics.units_per_em)
241 }
242
243 /// Get the height of a capital letter in the given font and size.
244 pub fn cap_height(&self, font_id: FontId, font_size: Pixels) -> Pixels {
245 self.read_metrics(font_id, |metrics| metrics.cap_height(font_size))
246 }
247
248 /// Get the height of the x character in the given font and size.
249 pub fn x_height(&self, font_id: FontId, font_size: Pixels) -> Pixels {
250 self.read_metrics(font_id, |metrics| metrics.x_height(font_size))
251 }
252
253 /// Get the recommended distance from the baseline for the given font
254 pub fn ascent(&self, font_id: FontId, font_size: Pixels) -> Pixels {
255 self.read_metrics(font_id, |metrics| metrics.ascent(font_size))
256 }
257
258 /// Get the recommended distance below the baseline for the given font,
259 /// in single spaced text.
260 pub fn descent(&self, font_id: FontId, font_size: Pixels) -> Pixels {
261 self.read_metrics(font_id, |metrics| metrics.descent(font_size))
262 }
263
264 /// Get the recommended baseline offset for the given font and line height.
265 pub fn baseline_offset(
266 &self,
267 font_id: FontId,
268 font_size: Pixels,
269 line_height: Pixels,
270 ) -> Pixels {
271 let ascent = self.ascent(font_id, font_size);
272 let descent = self.descent(font_id, font_size);
273 let padding_top = (line_height - ascent - descent) / 2.;
274 padding_top + ascent
275 }
276
277 fn read_metrics<T>(&self, font_id: FontId, read: impl FnOnce(&FontMetrics) -> T) -> T {
278 let lock = self.font_metrics.upgradable_read();
279
280 if let Some(metrics) = lock.get(&font_id) {
281 read(metrics)
282 } else {
283 let mut lock = RwLockUpgradableReadGuard::upgrade(lock);
284 let metrics = lock
285 .entry(font_id)
286 .or_insert_with(|| self.platform_text_system.font_metrics(font_id));
287 read(metrics)
288 }
289 }
290
291 /// Returns a handle to a line wrapper, for the given font and font size.
292 pub fn line_wrapper(self: &Arc<Self>, font: Font, font_size: Pixels) -> LineWrapperHandle {
293 let lock = &mut self.wrapper_pool.lock();
294 let font_id = self.resolve_font(&font);
295 let wrappers = lock
296 .entry(FontIdWithSize { font_id, font_size })
297 .or_default();
298 let wrapper = wrappers.pop().unwrap_or_else(|| {
299 LineWrapper::new(font_id, font_size, self.platform_text_system.clone())
300 });
301
302 LineWrapperHandle {
303 wrapper: Some(wrapper),
304 text_system: self.clone(),
305 }
306 }
307
308 /// Get the rasterized size and location of a specific, rendered glyph.
309 pub(crate) fn raster_bounds(&self, params: &RenderGlyphParams) -> Result<Bounds<DevicePixels>> {
310 let raster_bounds = self.raster_bounds.upgradable_read();
311 if let Some(bounds) = raster_bounds.get(params) {
312 Ok(*bounds)
313 } else {
314 let mut raster_bounds = RwLockUpgradableReadGuard::upgrade(raster_bounds);
315 let bounds = self.platform_text_system.glyph_raster_bounds(params)?;
316 raster_bounds.insert(params.clone(), bounds);
317 Ok(bounds)
318 }
319 }
320
321 pub(crate) fn rasterize_glyph(
322 &self,
323 params: &RenderGlyphParams,
324 ) -> Result<(Size<DevicePixels>, Vec<u8>)> {
325 let raster_bounds = self.raster_bounds(params)?;
326 self.platform_text_system
327 .rasterize_glyph(params, raster_bounds)
328 }
329}
330
331/// The GPUI text layout subsystem.
332#[derive(Deref)]
333pub struct WindowTextSystem {
334 line_layout_cache: LineLayoutCache,
335 #[deref]
336 text_system: Arc<TextSystem>,
337}
338
339impl WindowTextSystem {
340 pub(crate) fn new(text_system: Arc<TextSystem>) -> Self {
341 Self {
342 line_layout_cache: LineLayoutCache::new(text_system.platform_text_system.clone()),
343 text_system,
344 }
345 }
346
347 pub(crate) fn layout_index(&self) -> LineLayoutIndex {
348 self.line_layout_cache.layout_index()
349 }
350
351 pub(crate) fn reuse_layouts(&self, index: Range<LineLayoutIndex>) {
352 self.line_layout_cache.reuse_layouts(index)
353 }
354
355 pub(crate) fn truncate_layouts(&self, index: LineLayoutIndex) {
356 self.line_layout_cache.truncate_layouts(index)
357 }
358
359 /// Shape the given line, at the given font_size, for painting to the screen.
360 /// Subsets of the line can be styled independently with the `runs` parameter.
361 ///
362 /// Note that this method can only shape a single line of text. It will panic
363 /// if the text contains newlines. If you need to shape multiple lines of text,
364 /// use [`Self::shape_text`] instead.
365 pub fn shape_line(
366 &self,
367 text: SharedString,
368 font_size: Pixels,
369 runs: &[TextRun],
370 force_width: Option<Pixels>,
371 ) -> ShapedLine {
372 debug_assert!(
373 text.find('\n').is_none(),
374 "text argument should not contain newlines"
375 );
376
377 let mut decoration_runs = SmallVec::<[DecorationRun; 32]>::new();
378 for run in runs {
379 if let Some(last_run) = decoration_runs.last_mut()
380 && last_run.color == run.color
381 && last_run.underline == run.underline
382 && last_run.strikethrough == run.strikethrough
383 && last_run.background_color == run.background_color
384 {
385 last_run.len += run.len as u32;
386 continue;
387 }
388 decoration_runs.push(DecorationRun {
389 len: run.len as u32,
390 color: run.color,
391 background_color: run.background_color,
392 underline: run.underline,
393 strikethrough: run.strikethrough,
394 });
395 }
396
397 let layout = self.layout_line(&text, font_size, runs, force_width);
398
399 ShapedLine {
400 layout,
401 text,
402 decoration_runs,
403 }
404 }
405
406 /// Shape a multi line string of text, at the given font_size, for painting to the screen.
407 /// Subsets of the text can be styled independently with the `runs` parameter.
408 /// If `wrap_width` is provided, the line breaks will be adjusted to fit within the given width.
409 pub fn shape_text(
410 &self,
411 text: SharedString,
412 font_size: Pixels,
413 runs: &[TextRun],
414 wrap_width: Option<Pixels>,
415 line_clamp: Option<usize>,
416 ) -> Result<SmallVec<[WrappedLine; 1]>> {
417 let mut runs = runs.iter().filter(|run| run.len > 0).cloned().peekable();
418 let mut font_runs = self.font_runs_pool.lock().pop().unwrap_or_default();
419
420 let mut lines = SmallVec::new();
421 let mut line_start = 0;
422 let mut max_wrap_lines = line_clamp.unwrap_or(usize::MAX);
423 let mut wrapped_lines = 0;
424
425 let mut process_line = |line_text: SharedString| {
426 font_runs.clear();
427 let line_end = line_start + line_text.len();
428
429 let mut last_font: Option<FontId> = None;
430 let mut decoration_runs = SmallVec::<[DecorationRun; 32]>::new();
431 let mut run_start = line_start;
432 while run_start < line_end {
433 let Some(run) = runs.peek_mut() else {
434 break;
435 };
436
437 let run_len_within_line = cmp::min(line_end, run_start + run.len) - run_start;
438
439 let decoration_changed = if let Some(last_run) = decoration_runs.last_mut()
440 && last_run.color == run.color
441 && last_run.underline == run.underline
442 && last_run.strikethrough == run.strikethrough
443 && last_run.background_color == run.background_color
444 {
445 last_run.len += run_len_within_line as u32;
446 false
447 } else {
448 decoration_runs.push(DecorationRun {
449 len: run_len_within_line as u32,
450 color: run.color,
451 background_color: run.background_color,
452 underline: run.underline,
453 strikethrough: run.strikethrough,
454 });
455 true
456 };
457
458 if let Some(font_run) = font_runs.last_mut()
459 && Some(font_run.font_id) == last_font
460 && !decoration_changed
461 {
462 font_run.len += run_len_within_line;
463 } else {
464 let font_id = self.resolve_font(&run.font);
465 last_font = Some(font_id);
466 font_runs.push(FontRun {
467 len: run_len_within_line,
468 font_id,
469 });
470 }
471
472 if run_len_within_line == run.len {
473 runs.next();
474 } else {
475 // Preserve the remainder of the run for the next line
476 run.len -= run_len_within_line;
477 }
478 run_start += run_len_within_line;
479 }
480
481 let layout = self.line_layout_cache.layout_wrapped_line(
482 &line_text,
483 font_size,
484 &font_runs,
485 wrap_width,
486 Some(max_wrap_lines - wrapped_lines),
487 );
488 wrapped_lines += layout.wrap_boundaries.len();
489
490 lines.push(WrappedLine {
491 layout,
492 decoration_runs,
493 text: line_text,
494 });
495
496 // Skip `\n` character.
497 line_start = line_end + 1;
498 if let Some(run) = runs.peek_mut() {
499 run.len -= 1;
500 if run.len == 0 {
501 runs.next();
502 }
503 }
504 };
505
506 let mut split_lines = text.split('\n');
507 let mut processed = false;
508
509 if let Some(first_line) = split_lines.next()
510 && let Some(second_line) = split_lines.next()
511 {
512 processed = true;
513 process_line(first_line.to_string().into());
514 process_line(second_line.to_string().into());
515 for line_text in split_lines {
516 process_line(line_text.to_string().into());
517 }
518 }
519
520 if !processed {
521 process_line(text);
522 }
523
524 self.font_runs_pool.lock().push(font_runs);
525
526 Ok(lines)
527 }
528
529 pub(crate) fn finish_frame(&self) {
530 self.line_layout_cache.finish_frame()
531 }
532
533 /// Layout the given line of text, at the given font_size.
534 /// Subsets of the line can be styled independently with the `runs` parameter.
535 /// Generally, you should prefer to use [`Self::shape_line`] instead, which
536 /// can be painted directly.
537 pub fn layout_line(
538 &self,
539 text: &str,
540 font_size: Pixels,
541 runs: &[TextRun],
542 force_width: Option<Pixels>,
543 ) -> Arc<LineLayout> {
544 let mut last_run = None::<&TextRun>;
545 let mut last_font: Option<FontId> = None;
546 let mut font_runs = self.font_runs_pool.lock().pop().unwrap_or_default();
547 font_runs.clear();
548
549 for run in runs.iter() {
550 let decoration_changed = if let Some(last_run) = last_run
551 && last_run.color == run.color
552 && last_run.underline == run.underline
553 && last_run.strikethrough == run.strikethrough
554 // we do not consider differing background color relevant, as it does not affect glyphs
555 // && last_run.background_color == run.background_color
556 {
557 false
558 } else {
559 last_run = Some(run);
560 true
561 };
562
563 if let Some(font_run) = font_runs.last_mut()
564 && Some(font_run.font_id) == last_font
565 && !decoration_changed
566 {
567 font_run.len += run.len;
568 } else {
569 let font_id = self.resolve_font(&run.font);
570 last_font = Some(font_id);
571 font_runs.push(FontRun {
572 len: run.len,
573 font_id,
574 });
575 }
576 }
577
578 let layout = self.line_layout_cache.layout_line(
579 &SharedString::new(text),
580 font_size,
581 &font_runs,
582 force_width,
583 );
584
585 self.font_runs_pool.lock().push(font_runs);
586
587 layout
588 }
589}
590
591#[derive(Hash, Eq, PartialEq)]
592struct FontIdWithSize {
593 font_id: FontId,
594 font_size: Pixels,
595}
596
597/// A handle into the text system, which can be used to compute the wrapped layout of text
598pub struct LineWrapperHandle {
599 wrapper: Option<LineWrapper>,
600 text_system: Arc<TextSystem>,
601}
602
603impl Drop for LineWrapperHandle {
604 fn drop(&mut self) {
605 let mut state = self.text_system.wrapper_pool.lock();
606 let wrapper = self.wrapper.take().unwrap();
607 state
608 .get_mut(&FontIdWithSize {
609 font_id: wrapper.font_id,
610 font_size: wrapper.font_size,
611 })
612 .unwrap()
613 .push(wrapper);
614 }
615}
616
617impl Deref for LineWrapperHandle {
618 type Target = LineWrapper;
619
620 fn deref(&self) -> &Self::Target {
621 self.wrapper.as_ref().unwrap()
622 }
623}
624
625impl DerefMut for LineWrapperHandle {
626 fn deref_mut(&mut self) -> &mut Self::Target {
627 self.wrapper.as_mut().unwrap()
628 }
629}
630
631/// The degree of blackness or stroke thickness of a font. This value ranges from 100.0 to 900.0,
632/// with 400.0 as normal.
633#[derive(Clone, Copy, Debug, PartialEq, PartialOrd, Serialize, Deserialize, Add, Sub, FromStr)]
634#[serde(transparent)]
635pub struct FontWeight(pub f32);
636
637impl Display for FontWeight {
638 fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
639 write!(f, "{}", self.0)
640 }
641}
642
643impl From<f32> for FontWeight {
644 fn from(weight: f32) -> Self {
645 FontWeight(weight)
646 }
647}
648
649impl Default for FontWeight {
650 #[inline]
651 fn default() -> FontWeight {
652 FontWeight::NORMAL
653 }
654}
655
656impl Hash for FontWeight {
657 fn hash<H: Hasher>(&self, state: &mut H) {
658 state.write_u32(u32::from_be_bytes(self.0.to_be_bytes()));
659 }
660}
661
662impl Eq for FontWeight {}
663
664impl FontWeight {
665 /// Thin weight (100), the thinnest value.
666 pub const THIN: FontWeight = FontWeight(100.0);
667 /// Extra light weight (200).
668 pub const EXTRA_LIGHT: FontWeight = FontWeight(200.0);
669 /// Light weight (300).
670 pub const LIGHT: FontWeight = FontWeight(300.0);
671 /// Normal (400).
672 pub const NORMAL: FontWeight = FontWeight(400.0);
673 /// Medium weight (500, higher than normal).
674 pub const MEDIUM: FontWeight = FontWeight(500.0);
675 /// Semibold weight (600).
676 pub const SEMIBOLD: FontWeight = FontWeight(600.0);
677 /// Bold weight (700).
678 pub const BOLD: FontWeight = FontWeight(700.0);
679 /// Extra-bold weight (800).
680 pub const EXTRA_BOLD: FontWeight = FontWeight(800.0);
681 /// Black weight (900), the thickest value.
682 pub const BLACK: FontWeight = FontWeight(900.0);
683
684 /// All of the font weights, in order from thinnest to thickest.
685 pub const ALL: [FontWeight; 9] = [
686 Self::THIN,
687 Self::EXTRA_LIGHT,
688 Self::LIGHT,
689 Self::NORMAL,
690 Self::MEDIUM,
691 Self::SEMIBOLD,
692 Self::BOLD,
693 Self::EXTRA_BOLD,
694 Self::BLACK,
695 ];
696}
697
698impl schemars::JsonSchema for FontWeight {
699 fn schema_name() -> std::borrow::Cow<'static, str> {
700 "FontWeight".into()
701 }
702
703 fn json_schema(_: &mut schemars::SchemaGenerator) -> schemars::Schema {
704 use schemars::json_schema;
705 json_schema!({
706 "type": "number",
707 "minimum": Self::THIN,
708 "maximum": Self::BLACK,
709 "default": Self::default(),
710 "description": "Font weight value between 100 (thin) and 900 (black)"
711 })
712 }
713}
714
715/// Allows italic or oblique faces to be selected.
716#[derive(Clone, Copy, Eq, PartialEq, Debug, Hash, Default, Serialize, Deserialize, JsonSchema)]
717pub enum FontStyle {
718 /// A face that is neither italic not obliqued.
719 #[default]
720 Normal,
721 /// A form that is generally cursive in nature.
722 Italic,
723 /// A typically-sloped version of the regular face.
724 Oblique,
725}
726
727impl Display for FontStyle {
728 fn fmt(&self, f: &mut Formatter) -> fmt::Result {
729 Debug::fmt(self, f)
730 }
731}
732
733/// A styled run of text, for use in [`crate::TextLayout`].
734#[derive(Clone, Debug, PartialEq, Eq)]
735pub struct TextRun {
736 /// A number of utf8 bytes
737 pub len: usize,
738 /// The font to use for this run.
739 pub font: Font,
740 /// The color
741 pub color: Hsla,
742 /// The background color (if any)
743 pub background_color: Option<Hsla>,
744 /// The underline style (if any)
745 pub underline: Option<UnderlineStyle>,
746 /// The strikethrough style (if any)
747 pub strikethrough: Option<StrikethroughStyle>,
748}
749
750#[cfg(all(target_os = "macos", test))]
751impl TextRun {
752 fn with_len(&self, len: usize) -> Self {
753 let mut this = self.clone();
754 this.len = len;
755 this
756 }
757}
758
759/// An identifier for a specific glyph, as returned by [`WindowTextSystem::layout_line`].
760#[derive(Copy, Clone, Debug, Eq, PartialEq, Hash)]
761#[repr(C)]
762pub struct GlyphId(pub(crate) u32);
763
764#[derive(Clone, Debug, PartialEq)]
765pub(crate) struct RenderGlyphParams {
766 pub(crate) font_id: FontId,
767 pub(crate) glyph_id: GlyphId,
768 pub(crate) font_size: Pixels,
769 pub(crate) subpixel_variant: Point<u8>,
770 pub(crate) scale_factor: f32,
771 pub(crate) is_emoji: bool,
772}
773
774impl Eq for RenderGlyphParams {}
775
776impl Hash for RenderGlyphParams {
777 fn hash<H: Hasher>(&self, state: &mut H) {
778 self.font_id.0.hash(state);
779 self.glyph_id.0.hash(state);
780 self.font_size.0.to_bits().hash(state);
781 self.subpixel_variant.hash(state);
782 self.scale_factor.to_bits().hash(state);
783 self.is_emoji.hash(state);
784 }
785}
786
787/// The configuration details for identifying a specific font.
788#[derive(Clone, Debug, Eq, PartialEq, Hash)]
789pub struct Font {
790 /// The font family name.
791 ///
792 /// The special name ".SystemUIFont" is used to identify the system UI font, which varies based on platform.
793 pub family: SharedString,
794
795 /// The font features to use.
796 pub features: FontFeatures,
797
798 /// The fallbacks fonts to use.
799 pub fallbacks: Option<FontFallbacks>,
800
801 /// The font weight.
802 pub weight: FontWeight,
803
804 /// The font style.
805 pub style: FontStyle,
806}
807
808/// Get a [`Font`] for a given name.
809pub fn font(family: impl Into<SharedString>) -> Font {
810 Font {
811 family: family.into(),
812 features: FontFeatures::default(),
813 weight: FontWeight::default(),
814 style: FontStyle::default(),
815 fallbacks: None,
816 }
817}
818
819impl Font {
820 /// Set this Font to be bold
821 pub const fn bold(mut self) -> Self {
822 self.weight = FontWeight::BOLD;
823 self
824 }
825
826 /// Set this Font to be italic
827 pub const fn italic(mut self) -> Self {
828 self.style = FontStyle::Italic;
829 self
830 }
831}
832
833/// A struct for storing font metrics.
834/// It is used to define the measurements of a typeface.
835#[derive(Clone, Copy, Debug)]
836pub struct FontMetrics {
837 /// The number of font units that make up the "em square",
838 /// a scalable grid for determining the size of a typeface.
839 pub(crate) units_per_em: u32,
840
841 /// The vertical distance from the baseline of the font to the top of the glyph covers.
842 pub(crate) ascent: f32,
843
844 /// The vertical distance from the baseline of the font to the bottom of the glyph covers.
845 pub(crate) descent: f32,
846
847 /// The recommended additional space to add between lines of type.
848 pub(crate) line_gap: f32,
849
850 /// The suggested position of the underline.
851 pub(crate) underline_position: f32,
852
853 /// The suggested thickness of the underline.
854 pub(crate) underline_thickness: f32,
855
856 /// The height of a capital letter measured from the baseline of the font.
857 pub(crate) cap_height: f32,
858
859 /// The height of a lowercase x.
860 pub(crate) x_height: f32,
861
862 /// The outer limits of the area that the font covers.
863 /// Corresponds to the xMin / xMax / yMin / yMax values in the OpenType `head` table
864 pub(crate) bounding_box: Bounds<f32>,
865}
866
867impl FontMetrics {
868 /// Returns the vertical distance from the baseline of the font to the top of the glyph covers in pixels.
869 pub fn ascent(&self, font_size: Pixels) -> Pixels {
870 Pixels((self.ascent / self.units_per_em as f32) * font_size.0)
871 }
872
873 /// Returns the vertical distance from the baseline of the font to the bottom of the glyph covers in pixels.
874 pub fn descent(&self, font_size: Pixels) -> Pixels {
875 Pixels((self.descent / self.units_per_em as f32) * font_size.0)
876 }
877
878 /// Returns the recommended additional space to add between lines of type in pixels.
879 pub fn line_gap(&self, font_size: Pixels) -> Pixels {
880 Pixels((self.line_gap / self.units_per_em as f32) * font_size.0)
881 }
882
883 /// Returns the suggested position of the underline in pixels.
884 pub fn underline_position(&self, font_size: Pixels) -> Pixels {
885 Pixels((self.underline_position / self.units_per_em as f32) * font_size.0)
886 }
887
888 /// Returns the suggested thickness of the underline in pixels.
889 pub fn underline_thickness(&self, font_size: Pixels) -> Pixels {
890 Pixels((self.underline_thickness / self.units_per_em as f32) * font_size.0)
891 }
892
893 /// Returns the height of a capital letter measured from the baseline of the font in pixels.
894 pub fn cap_height(&self, font_size: Pixels) -> Pixels {
895 Pixels((self.cap_height / self.units_per_em as f32) * font_size.0)
896 }
897
898 /// Returns the height of a lowercase x in pixels.
899 pub fn x_height(&self, font_size: Pixels) -> Pixels {
900 Pixels((self.x_height / self.units_per_em as f32) * font_size.0)
901 }
902
903 /// Returns the outer limits of the area that the font covers in pixels.
904 pub fn bounding_box(&self, font_size: Pixels) -> Bounds<Pixels> {
905 (self.bounding_box / self.units_per_em as f32 * font_size.0).map(px)
906 }
907}
908
909#[allow(unused)]
910pub(crate) fn font_name_with_fallbacks<'a>(name: &'a str, system: &'a str) -> &'a str {
911 // Note: the "Zed Plex" fonts were deprecated as we are not allowed to use "Plex"
912 // in a derived font name. They are essentially indistinguishable from IBM Plex/Lilex,
913 // and so retained here for backward compatibility.
914 match name {
915 ".SystemUIFont" => system,
916 ".ZedSans" | "Zed Plex Sans" => "IBM Plex Sans",
917 ".ZedMono" | "Zed Plex Mono" => "Lilex",
918 _ => name,
919 }
920}