1use crate::{
2 color::Color,
3 fonts::{FontId, GlyphId},
4 geometry::{
5 rect::RectF,
6 vector::{vec2f, Vector2F},
7 },
8 platform, scene, FontSystem, PaintContext,
9};
10use lazy_static::lazy_static;
11use ordered_float::OrderedFloat;
12use parking_lot::{Mutex, RwLock, RwLockUpgradableReadGuard};
13use smallvec::SmallVec;
14use std::{
15 borrow::Borrow,
16 collections::HashMap,
17 hash::{Hash, Hasher},
18 iter,
19 ops::{Deref, DerefMut},
20 sync::Arc,
21};
22
23pub struct TextLayoutCache {
24 prev_frame: Mutex<HashMap<CacheKeyValue, Arc<LineLayout>>>,
25 curr_frame: RwLock<HashMap<CacheKeyValue, Arc<LineLayout>>>,
26 fonts: Arc<dyn platform::FontSystem>,
27}
28
29impl TextLayoutCache {
30 pub fn new(fonts: Arc<dyn platform::FontSystem>) -> Self {
31 Self {
32 prev_frame: Mutex::new(HashMap::new()),
33 curr_frame: RwLock::new(HashMap::new()),
34 fonts,
35 }
36 }
37
38 pub fn finish_frame(&self) {
39 let mut prev_frame = self.prev_frame.lock();
40 let mut curr_frame = self.curr_frame.write();
41 std::mem::swap(&mut *prev_frame, &mut *curr_frame);
42 curr_frame.clear();
43 }
44
45 pub fn layout_str<'a>(
46 &'a self,
47 text: &'a str,
48 font_size: f32,
49 runs: &'a [(usize, FontId, Color)],
50 ) -> Line {
51 let key = &CacheKeyRef {
52 text,
53 font_size: OrderedFloat(font_size),
54 runs,
55 } as &dyn CacheKey;
56 let curr_frame = self.curr_frame.upgradable_read();
57 if let Some(layout) = curr_frame.get(key) {
58 return Line::new(layout.clone(), runs);
59 }
60
61 let mut curr_frame = RwLockUpgradableReadGuard::upgrade(curr_frame);
62 if let Some((key, layout)) = self.prev_frame.lock().remove_entry(key) {
63 curr_frame.insert(key, layout.clone());
64 Line::new(layout.clone(), runs)
65 } else {
66 let layout = Arc::new(self.fonts.layout_line(text, font_size, runs));
67 let key = CacheKeyValue {
68 text: text.into(),
69 font_size: OrderedFloat(font_size),
70 runs: SmallVec::from(runs),
71 };
72 curr_frame.insert(key, layout.clone());
73 Line::new(layout, runs)
74 }
75 }
76}
77
78trait CacheKey {
79 fn key<'a>(&'a self) -> CacheKeyRef<'a>;
80}
81
82impl<'a> PartialEq for (dyn CacheKey + 'a) {
83 fn eq(&self, other: &dyn CacheKey) -> bool {
84 self.key() == other.key()
85 }
86}
87
88impl<'a> Eq for (dyn CacheKey + 'a) {}
89
90impl<'a> Hash for (dyn CacheKey + 'a) {
91 fn hash<H: Hasher>(&self, state: &mut H) {
92 self.key().hash(state)
93 }
94}
95
96#[derive(Eq, PartialEq)]
97struct CacheKeyValue {
98 text: String,
99 font_size: OrderedFloat<f32>,
100 runs: SmallVec<[(usize, FontId, Color); 1]>,
101}
102
103impl CacheKey for CacheKeyValue {
104 fn key<'a>(&'a self) -> CacheKeyRef<'a> {
105 CacheKeyRef {
106 text: &self.text.as_str(),
107 font_size: self.font_size,
108 runs: self.runs.as_slice(),
109 }
110 }
111}
112
113impl Hash for CacheKeyValue {
114 fn hash<H: Hasher>(&self, state: &mut H) {
115 self.key().hash(state);
116 }
117}
118
119impl<'a> Borrow<dyn CacheKey + 'a> for CacheKeyValue {
120 fn borrow(&self) -> &(dyn CacheKey + 'a) {
121 self as &dyn CacheKey
122 }
123}
124
125#[derive(Copy, Clone, PartialEq, Eq, Hash)]
126struct CacheKeyRef<'a> {
127 text: &'a str,
128 font_size: OrderedFloat<f32>,
129 runs: &'a [(usize, FontId, Color)],
130}
131
132impl<'a> CacheKey for CacheKeyRef<'a> {
133 fn key<'b>(&'b self) -> CacheKeyRef<'b> {
134 *self
135 }
136}
137
138#[derive(Default, Debug)]
139pub struct Line {
140 layout: Arc<LineLayout>,
141 color_runs: SmallVec<[(u32, Color); 32]>,
142}
143
144#[derive(Default, Debug)]
145pub struct LineLayout {
146 pub width: f32,
147 pub ascent: f32,
148 pub descent: f32,
149 pub runs: Vec<Run>,
150 pub len: usize,
151 pub font_size: f32,
152}
153
154#[derive(Debug)]
155pub struct Run {
156 pub font_id: FontId,
157 pub glyphs: Vec<Glyph>,
158}
159
160#[derive(Debug)]
161pub struct Glyph {
162 pub id: GlyphId,
163 pub position: Vector2F,
164 pub index: usize,
165}
166
167impl Line {
168 fn new(layout: Arc<LineLayout>, runs: &[(usize, FontId, Color)]) -> Self {
169 let mut color_runs = SmallVec::new();
170 for (len, _, color) in runs {
171 color_runs.push((*len as u32, *color));
172 }
173 Self { layout, color_runs }
174 }
175
176 pub fn runs(&self) -> &[Run] {
177 &self.layout.runs
178 }
179
180 pub fn width(&self) -> f32 {
181 self.layout.width
182 }
183
184 pub fn x_for_index(&self, index: usize) -> f32 {
185 for run in &self.layout.runs {
186 for glyph in &run.glyphs {
187 if glyph.index == index {
188 return glyph.position.x();
189 }
190 }
191 }
192 self.layout.width
193 }
194
195 pub fn index_for_x(&self, x: f32) -> Option<usize> {
196 if x >= self.layout.width {
197 None
198 } else {
199 for run in self.layout.runs.iter().rev() {
200 for glyph in run.glyphs.iter().rev() {
201 if glyph.position.x() <= x {
202 return Some(glyph.index);
203 }
204 }
205 }
206 Some(0)
207 }
208 }
209
210 pub fn paint(&self, origin: Vector2F, visible_bounds: RectF, cx: &mut PaintContext) {
211 let padding_top = (visible_bounds.height() - self.layout.ascent - self.layout.descent) / 2.;
212 let baseline_origin = vec2f(0., padding_top + self.layout.ascent);
213
214 let mut color_runs = self.color_runs.iter();
215 let mut color_end = 0;
216 let mut color = Color::black();
217
218 for run in &self.layout.runs {
219 let max_glyph_width = cx
220 .font_cache
221 .bounding_box(run.font_id, self.layout.font_size)
222 .x();
223
224 for glyph in &run.glyphs {
225 let glyph_origin = baseline_origin + glyph.position;
226
227 if glyph_origin.x() + max_glyph_width < visible_bounds.origin().x() {
228 continue;
229 }
230 if glyph_origin.x() > visible_bounds.upper_right().x() {
231 break;
232 }
233
234 if glyph.index >= color_end {
235 if let Some(next_run) = color_runs.next() {
236 color_end += next_run.0 as usize;
237 color = next_run.1;
238 } else {
239 color_end = self.layout.len;
240 color = Color::black();
241 }
242 }
243
244 cx.scene.push_glyph(scene::Glyph {
245 font_id: run.font_id,
246 font_size: self.layout.font_size,
247 id: glyph.id,
248 origin: origin + glyph_origin,
249 color,
250 });
251 }
252 }
253 }
254
255 pub fn paint_wrapped(
256 &self,
257 origin: Vector2F,
258 line_height: f32,
259 boundaries: impl IntoIterator<Item = ShapedBoundary>,
260 cx: &mut PaintContext,
261 ) {
262 let padding_top = (line_height - self.layout.ascent - self.layout.descent) / 2.;
263 let baseline_origin = vec2f(0., padding_top + self.layout.ascent);
264
265 let mut boundaries = boundaries.into_iter().peekable();
266 let mut color_runs = self.color_runs.iter();
267 let mut color_end = 0;
268 let mut color = Color::black();
269
270 let mut glyph_origin = baseline_origin;
271 let mut prev_position = 0.;
272 for run in &self.layout.runs {
273 for (glyph_ix, glyph) in run.glyphs.iter().enumerate() {
274 if boundaries.peek().map_or(false, |b| b.glyph_ix == glyph_ix) {
275 boundaries.next();
276 glyph_origin = vec2f(0., glyph_origin.y() + line_height);
277 } else {
278 glyph_origin.set_x(glyph_origin.x() + glyph.position.x() - prev_position);
279 }
280 prev_position = glyph.position.x();
281
282 if glyph.index >= color_end {
283 if let Some(next_run) = color_runs.next() {
284 color_end += next_run.0 as usize;
285 color = next_run.1;
286 } else {
287 color_end = self.layout.len;
288 color = Color::black();
289 }
290 }
291
292 cx.scene.push_glyph(scene::Glyph {
293 font_id: run.font_id,
294 font_size: self.layout.font_size,
295 id: glyph.id,
296 origin: origin + glyph_origin,
297 color,
298 });
299 }
300 }
301 }
302}
303
304impl Run {
305 pub fn glyphs(&self) -> &[Glyph] {
306 &self.glyphs
307 }
308}
309
310lazy_static! {
311 static ref WRAPPER_POOL: Mutex<Vec<LineWrapper>> = Default::default();
312}
313
314#[derive(Copy, Clone, Debug, PartialEq, Eq)]
315pub struct Boundary {
316 pub ix: usize,
317 pub next_indent: u32,
318}
319
320#[derive(Clone, Copy, Debug, PartialEq, Eq, PartialOrd, Ord)]
321pub struct ShapedBoundary {
322 pub run_ix: usize,
323 pub glyph_ix: usize,
324}
325
326impl Boundary {
327 fn new(ix: usize, next_indent: u32) -> Self {
328 Self { ix, next_indent }
329 }
330}
331
332pub struct LineWrapper {
333 font_system: Arc<dyn FontSystem>,
334 font_id: FontId,
335 font_size: f32,
336 cached_ascii_char_widths: [f32; 128],
337 cached_other_char_widths: HashMap<char, f32>,
338}
339
340impl LineWrapper {
341 pub const MAX_INDENT: u32 = 256;
342
343 pub fn acquire(
344 font_id: FontId,
345 font_size: f32,
346 font_system: Arc<dyn FontSystem>,
347 ) -> LineWrapperHandle {
348 let wrapper = if let Some(mut wrapper) = WRAPPER_POOL.lock().pop() {
349 if wrapper.font_id != font_id || wrapper.font_size != font_size {
350 wrapper.cached_ascii_char_widths = [f32::NAN; 128];
351 wrapper.cached_other_char_widths.clear();
352 }
353 wrapper
354 } else {
355 LineWrapper::new(font_id, font_size, font_system)
356 };
357 LineWrapperHandle(Some(wrapper))
358 }
359
360 pub fn new(font_id: FontId, font_size: f32, font_system: Arc<dyn FontSystem>) -> Self {
361 Self {
362 font_system,
363 font_id,
364 font_size,
365 cached_ascii_char_widths: [f32::NAN; 128],
366 cached_other_char_widths: HashMap::new(),
367 }
368 }
369
370 pub fn wrap_line<'a>(
371 &'a mut self,
372 line: &'a str,
373 wrap_width: f32,
374 ) -> impl Iterator<Item = Boundary> + 'a {
375 let mut width = 0.0;
376 let mut first_non_whitespace_ix = None;
377 let mut indent = None;
378 let mut last_candidate_ix = 0;
379 let mut last_candidate_width = 0.0;
380 let mut last_wrap_ix = 0;
381 let mut prev_c = '\0';
382 let mut char_indices = line.char_indices();
383 iter::from_fn(move || {
384 while let Some((ix, c)) = char_indices.next() {
385 if c == '\n' {
386 continue;
387 }
388
389 if self.is_boundary(prev_c, c) && first_non_whitespace_ix.is_some() {
390 last_candidate_ix = ix;
391 last_candidate_width = width;
392 }
393
394 if c != ' ' && first_non_whitespace_ix.is_none() {
395 first_non_whitespace_ix = Some(ix);
396 }
397
398 let char_width = self.width_for_char(c);
399 width += char_width;
400 if width > wrap_width && ix > last_wrap_ix {
401 if let (None, Some(first_non_whitespace_ix)) = (indent, first_non_whitespace_ix)
402 {
403 indent = Some(
404 Self::MAX_INDENT.min((first_non_whitespace_ix - last_wrap_ix) as u32),
405 );
406 }
407
408 if last_candidate_ix > 0 {
409 last_wrap_ix = last_candidate_ix;
410 width -= last_candidate_width;
411 last_candidate_ix = 0;
412 } else {
413 last_wrap_ix = ix;
414 width = char_width;
415 }
416
417 let indent_width =
418 indent.map(|indent| indent as f32 * self.width_for_char(' '));
419 width += indent_width.unwrap_or(0.);
420
421 return Some(Boundary::new(last_wrap_ix, indent.unwrap_or(0)));
422 }
423 prev_c = c;
424 }
425
426 None
427 })
428 }
429
430 pub fn wrap_shaped_line<'a>(
431 &'a mut self,
432 str: &'a str,
433 line: &'a Line,
434 wrap_width: f32,
435 ) -> impl Iterator<Item = ShapedBoundary> + 'a {
436 let mut first_non_whitespace_ix = None;
437 let mut last_candidate_ix = None;
438 let mut last_candidate_x = 0.0;
439 let mut last_wrap_ix = ShapedBoundary {
440 run_ix: 0,
441 glyph_ix: 0,
442 };
443 let mut last_wrap_x = 0.;
444 let mut prev_c = '\0';
445 let mut glyphs = line
446 .runs()
447 .iter()
448 .enumerate()
449 .flat_map(move |(run_ix, run)| {
450 run.glyphs()
451 .iter()
452 .enumerate()
453 .map(move |(glyph_ix, glyph)| {
454 let character = str[glyph.index..].chars().next().unwrap();
455 (
456 ShapedBoundary { run_ix, glyph_ix },
457 character,
458 glyph.position.x(),
459 )
460 })
461 })
462 .peekable();
463
464 iter::from_fn(move || {
465 while let Some((ix, c, x)) = glyphs.next() {
466 if c == '\n' {
467 continue;
468 }
469
470 if self.is_boundary(prev_c, c) && first_non_whitespace_ix.is_some() {
471 last_candidate_ix = Some(ix);
472 last_candidate_x = x;
473 }
474
475 if c != ' ' && first_non_whitespace_ix.is_none() {
476 first_non_whitespace_ix = Some(ix);
477 }
478
479 let next_x = glyphs.peek().map_or(line.width(), |(_, _, x)| *x);
480 let width = next_x - last_wrap_x;
481 if width > wrap_width && ix > last_wrap_ix {
482 if let Some(last_candidate_ix) = last_candidate_ix.take() {
483 last_wrap_ix = last_candidate_ix;
484 last_wrap_x = last_candidate_x;
485 } else {
486 last_wrap_ix = ix;
487 last_wrap_x = x;
488 }
489
490 return Some(last_wrap_ix);
491 }
492 prev_c = c;
493 }
494
495 None
496 })
497 }
498
499 fn is_boundary(&self, prev: char, next: char) -> bool {
500 (prev == ' ') && (next != ' ')
501 }
502
503 #[inline(always)]
504 fn width_for_char(&mut self, c: char) -> f32 {
505 if (c as u32) < 128 {
506 let mut width = self.cached_ascii_char_widths[c as usize];
507 if width.is_nan() {
508 width = self.compute_width_for_char(c);
509 self.cached_ascii_char_widths[c as usize] = width;
510 }
511 width
512 } else {
513 let mut width = self
514 .cached_other_char_widths
515 .get(&c)
516 .copied()
517 .unwrap_or(f32::NAN);
518 if width.is_nan() {
519 width = self.compute_width_for_char(c);
520 self.cached_other_char_widths.insert(c, width);
521 }
522 width
523 }
524 }
525
526 fn compute_width_for_char(&self, c: char) -> f32 {
527 self.font_system
528 .layout_line(
529 &c.to_string(),
530 self.font_size,
531 &[(1, self.font_id, Default::default())],
532 )
533 .width
534 }
535}
536
537pub struct LineWrapperHandle(Option<LineWrapper>);
538
539impl Drop for LineWrapperHandle {
540 fn drop(&mut self) {
541 let wrapper = self.0.take().unwrap();
542 WRAPPER_POOL.lock().push(wrapper)
543 }
544}
545
546impl Deref for LineWrapperHandle {
547 type Target = LineWrapper;
548
549 fn deref(&self) -> &Self::Target {
550 self.0.as_ref().unwrap()
551 }
552}
553
554impl DerefMut for LineWrapperHandle {
555 fn deref_mut(&mut self) -> &mut Self::Target {
556 self.0.as_mut().unwrap()
557 }
558}
559
560#[cfg(test)]
561mod tests {
562 use super::*;
563 use crate::{
564 color::Color,
565 fonts::{Properties, Weight},
566 };
567
568 #[crate::test(self)]
569 fn test_wrap_line(cx: &mut crate::MutableAppContext) {
570 let font_cache = cx.font_cache().clone();
571 let font_system = cx.platform().fonts();
572 let family = font_cache.load_family(&["Courier"]).unwrap();
573 let font_id = font_cache.select_font(family, &Default::default()).unwrap();
574
575 let mut wrapper = LineWrapper::new(font_id, 16., font_system);
576 assert_eq!(
577 wrapper
578 .wrap_line("aa bbb cccc ddddd eeee", 72.0)
579 .collect::<Vec<_>>(),
580 &[
581 Boundary::new(7, 0),
582 Boundary::new(12, 0),
583 Boundary::new(18, 0)
584 ],
585 );
586 assert_eq!(
587 wrapper
588 .wrap_line("aaa aaaaaaaaaaaaaaaaaa", 72.0)
589 .collect::<Vec<_>>(),
590 &[
591 Boundary::new(4, 0),
592 Boundary::new(11, 0),
593 Boundary::new(18, 0)
594 ],
595 );
596 assert_eq!(
597 wrapper.wrap_line(" aaaaaaa", 72.).collect::<Vec<_>>(),
598 &[
599 Boundary::new(7, 5),
600 Boundary::new(9, 5),
601 Boundary::new(11, 5),
602 ]
603 );
604 assert_eq!(
605 wrapper
606 .wrap_line(" ", 72.)
607 .collect::<Vec<_>>(),
608 &[
609 Boundary::new(7, 0),
610 Boundary::new(14, 0),
611 Boundary::new(21, 0)
612 ]
613 );
614 assert_eq!(
615 wrapper
616 .wrap_line(" aaaaaaaaaaaaaa", 72.)
617 .collect::<Vec<_>>(),
618 &[
619 Boundary::new(7, 0),
620 Boundary::new(14, 3),
621 Boundary::new(18, 3),
622 Boundary::new(22, 3),
623 ]
624 );
625 }
626
627 #[crate::test(self)]
628 fn test_wrap_shaped_line(cx: &mut crate::MutableAppContext) {
629 let font_cache = cx.font_cache().clone();
630 let font_system = cx.platform().fonts();
631 let text_layout_cache = TextLayoutCache::new(font_system.clone());
632
633 let family = font_cache.load_family(&["Helvetica"]).unwrap();
634 let font_id = font_cache.select_font(family, &Default::default()).unwrap();
635 let normal = font_cache.select_font(family, &Default::default()).unwrap();
636 let bold = font_cache
637 .select_font(
638 family,
639 &Properties {
640 weight: Weight::BOLD,
641 ..Default::default()
642 },
643 )
644 .unwrap();
645
646 let text = "aa bbb cccc ddddd eeee";
647 let line = text_layout_cache.layout_str(
648 text,
649 16.0,
650 &[
651 (4, normal, Color::default()),
652 (5, bold, Color::default()),
653 (6, normal, Color::default()),
654 (1, bold, Color::default()),
655 (7, normal, Color::default()),
656 ],
657 );
658
659 let mut wrapper = LineWrapper::new(font_id, 16., font_system);
660 assert_eq!(
661 wrapper
662 .wrap_shaped_line(&text, &line, 72.0)
663 .collect::<Vec<_>>(),
664 &[
665 ShapedBoundary {
666 run_ix: 1,
667 glyph_ix: 3
668 },
669 ShapedBoundary {
670 run_ix: 2,
671 glyph_ix: 3
672 },
673 ShapedBoundary {
674 run_ix: 4,
675 glyph_ix: 2
676 }
677 ],
678 );
679 }
680}