1use crate::{
2 black, fill, point, px, size, App, Bounds, Half, Hsla, LineLayout, Pixels, Point, Result,
3 SharedString, StrikethroughStyle, TextAlign, UnderlineStyle, Window, WrapBoundary,
4 WrappedLineLayout,
5};
6use derive_more::{Deref, DerefMut};
7use smallvec::SmallVec;
8use std::sync::Arc;
9
10/// Set the text decoration for a run of text.
11#[derive(Debug, Clone)]
12pub struct DecorationRun {
13 /// The length of the run in utf-8 bytes.
14 pub len: u32,
15
16 /// The color for this run
17 pub color: Hsla,
18
19 /// The background color for this run
20 pub background_color: Option<Hsla>,
21
22 /// The underline style for this run
23 pub underline: Option<UnderlineStyle>,
24
25 /// The strikethrough style for this run
26 pub strikethrough: Option<StrikethroughStyle>,
27}
28
29/// A line of text that has been shaped and decorated.
30#[derive(Clone, Default, Debug, Deref, DerefMut)]
31pub struct ShapedLine {
32 #[deref]
33 #[deref_mut]
34 pub(crate) layout: Arc<LineLayout>,
35 /// The text that was shaped for this line.
36 pub text: SharedString,
37 pub(crate) decoration_runs: SmallVec<[DecorationRun; 32]>,
38}
39
40impl ShapedLine {
41 /// The length of the line in utf-8 bytes.
42 #[allow(clippy::len_without_is_empty)]
43 pub fn len(&self) -> usize {
44 self.layout.len
45 }
46
47 /// Override the len, useful if you're rendering text a
48 /// as text b (e.g. rendering invisibles).
49 pub fn with_len(mut self, len: usize) -> Self {
50 let layout = self.layout.as_ref();
51 self.layout = Arc::new(LineLayout {
52 font_size: layout.font_size,
53 width: layout.width,
54 ascent: layout.ascent,
55 descent: layout.descent,
56 runs: layout.runs.clone(),
57 len,
58 });
59 self
60 }
61
62 /// Paint the line of text to the window.
63 pub fn paint(
64 &self,
65 origin: Point<Pixels>,
66 line_height: Pixels,
67 window: &mut Window,
68 cx: &mut App,
69 ) -> Result<()> {
70 paint_line(
71 origin,
72 &self.layout,
73 line_height,
74 TextAlign::default(),
75 None,
76 &self.decoration_runs,
77 &[],
78 window,
79 cx,
80 )?;
81
82 Ok(())
83 }
84
85 /// Paint the background of the line to the window.
86 pub fn paint_background(
87 &self,
88 origin: Point<Pixels>,
89 line_height: Pixels,
90 window: &mut Window,
91 cx: &mut App,
92 ) -> Result<()> {
93 paint_line_background(
94 origin,
95 &self.layout,
96 line_height,
97 TextAlign::default(),
98 None,
99 &self.decoration_runs,
100 &[],
101 window,
102 cx,
103 )?;
104
105 Ok(())
106 }
107}
108
109/// A line of text that has been shaped, decorated, and wrapped by the text layout system.
110#[derive(Clone, Default, Debug, Deref, DerefMut)]
111pub struct WrappedLine {
112 #[deref]
113 #[deref_mut]
114 pub(crate) layout: Arc<WrappedLineLayout>,
115 /// The text that was shaped for this line.
116 pub text: SharedString,
117 pub(crate) decoration_runs: SmallVec<[DecorationRun; 32]>,
118}
119
120impl WrappedLine {
121 /// The length of the underlying, unwrapped layout, in utf-8 bytes.
122 #[allow(clippy::len_without_is_empty)]
123 pub fn len(&self) -> usize {
124 self.layout.len()
125 }
126
127 /// Paint this line of text to the window.
128 pub fn paint(
129 &self,
130 origin: Point<Pixels>,
131 line_height: Pixels,
132 align: TextAlign,
133 bounds: Option<Bounds<Pixels>>,
134 window: &mut Window,
135 cx: &mut App,
136 ) -> Result<()> {
137 let align_width = match bounds {
138 Some(bounds) => Some(bounds.size.width),
139 None => self.layout.wrap_width,
140 };
141
142 paint_line(
143 origin,
144 &self.layout.unwrapped_layout,
145 line_height,
146 align,
147 align_width,
148 &self.decoration_runs,
149 &self.wrap_boundaries,
150 window,
151 cx,
152 )?;
153
154 Ok(())
155 }
156}
157
158fn paint_line(
159 origin: Point<Pixels>,
160 layout: &LineLayout,
161 line_height: Pixels,
162 align: TextAlign,
163 align_width: Option<Pixels>,
164 decoration_runs: &[DecorationRun],
165 wrap_boundaries: &[WrapBoundary],
166 window: &mut Window,
167 cx: &mut App,
168) -> Result<()> {
169 let line_bounds = Bounds::new(
170 origin,
171 size(
172 layout.width,
173 line_height * (wrap_boundaries.len() as f32 + 1.),
174 ),
175 );
176 window.paint_layer(line_bounds, |window| {
177 let padding_top = (line_height - layout.ascent - layout.descent) / 2.;
178 let baseline_offset = point(px(0.), padding_top + layout.ascent);
179 let mut decoration_runs = decoration_runs.iter();
180 let mut wraps = wrap_boundaries.iter().peekable();
181 let mut run_end = 0;
182 let mut color = black();
183 let mut current_underline: Option<(Point<Pixels>, UnderlineStyle)> = None;
184 let mut current_strikethrough: Option<(Point<Pixels>, StrikethroughStyle)> = None;
185 let text_system = cx.text_system().clone();
186 let mut glyph_origin = point(
187 aligned_origin_x(
188 origin,
189 align_width.unwrap_or(layout.width),
190 px(0.0),
191 &align,
192 layout,
193 wraps.peek(),
194 ),
195 origin.y,
196 );
197 let mut prev_glyph_position = Point::default();
198 let mut max_glyph_size = size(px(0.), px(0.));
199 for (run_ix, run) in layout.runs.iter().enumerate() {
200 max_glyph_size = text_system.bounding_box(run.font_id, layout.font_size).size;
201
202 for (glyph_ix, glyph) in run.glyphs.iter().enumerate() {
203 glyph_origin.x += glyph.position.x - prev_glyph_position.x;
204
205 if wraps.peek() == Some(&&WrapBoundary { run_ix, glyph_ix }) {
206 wraps.next();
207 if let Some((underline_origin, underline_style)) = current_underline.as_mut() {
208 if glyph_origin.x == underline_origin.x {
209 underline_origin.x -= max_glyph_size.width.half();
210 };
211 window.paint_underline(
212 *underline_origin,
213 glyph_origin.x - underline_origin.x,
214 underline_style,
215 );
216 underline_origin.x = origin.x;
217 underline_origin.y += line_height;
218 }
219 if let Some((strikethrough_origin, strikethrough_style)) =
220 current_strikethrough.as_mut()
221 {
222 if glyph_origin.x == strikethrough_origin.x {
223 strikethrough_origin.x -= max_glyph_size.width.half();
224 };
225 window.paint_strikethrough(
226 *strikethrough_origin,
227 glyph_origin.x - strikethrough_origin.x,
228 strikethrough_style,
229 );
230 strikethrough_origin.x = origin.x;
231 strikethrough_origin.y += line_height;
232 }
233
234 glyph_origin.x = aligned_origin_x(
235 origin,
236 align_width.unwrap_or(layout.width),
237 glyph.position.x,
238 &align,
239 layout,
240 wraps.peek(),
241 );
242 glyph_origin.y += line_height;
243 }
244 prev_glyph_position = glyph.position;
245
246 let mut finished_underline: Option<(Point<Pixels>, UnderlineStyle)> = None;
247 let mut finished_strikethrough: Option<(Point<Pixels>, StrikethroughStyle)> = None;
248 if glyph.index >= run_end {
249 let mut style_run = decoration_runs.next();
250
251 // ignore style runs that apply to a partial glyph
252 while let Some(run) = style_run {
253 if glyph.index < run_end + (run.len as usize) {
254 break;
255 }
256 run_end += run.len as usize;
257 style_run = decoration_runs.next();
258 }
259
260 if let Some(style_run) = style_run {
261 if let Some((_, underline_style)) = &mut current_underline {
262 if style_run.underline.as_ref() != Some(underline_style) {
263 finished_underline = current_underline.take();
264 }
265 }
266 if let Some(run_underline) = style_run.underline.as_ref() {
267 current_underline.get_or_insert((
268 point(
269 glyph_origin.x,
270 glyph_origin.y + baseline_offset.y + (layout.descent * 0.618),
271 ),
272 UnderlineStyle {
273 color: Some(run_underline.color.unwrap_or(style_run.color)),
274 thickness: run_underline.thickness,
275 wavy: run_underline.wavy,
276 },
277 ));
278 }
279 if let Some((_, strikethrough_style)) = &mut current_strikethrough {
280 if style_run.strikethrough.as_ref() != Some(strikethrough_style) {
281 finished_strikethrough = current_strikethrough.take();
282 }
283 }
284 if let Some(run_strikethrough) = style_run.strikethrough.as_ref() {
285 current_strikethrough.get_or_insert((
286 point(
287 glyph_origin.x,
288 glyph_origin.y
289 + (((layout.ascent * 0.5) + baseline_offset.y) * 0.5),
290 ),
291 StrikethroughStyle {
292 color: Some(run_strikethrough.color.unwrap_or(style_run.color)),
293 thickness: run_strikethrough.thickness,
294 },
295 ));
296 }
297
298 run_end += style_run.len as usize;
299 color = style_run.color;
300 } else {
301 run_end = layout.len;
302 finished_underline = current_underline.take();
303 finished_strikethrough = current_strikethrough.take();
304 }
305 }
306
307 if let Some((mut underline_origin, underline_style)) = finished_underline {
308 if underline_origin.x == glyph_origin.x {
309 underline_origin.x -= max_glyph_size.width.half();
310 };
311 window.paint_underline(
312 underline_origin,
313 glyph_origin.x - underline_origin.x,
314 &underline_style,
315 );
316 }
317
318 if let Some((mut strikethrough_origin, strikethrough_style)) =
319 finished_strikethrough
320 {
321 if strikethrough_origin.x == glyph_origin.x {
322 strikethrough_origin.x -= max_glyph_size.width.half();
323 };
324 window.paint_strikethrough(
325 strikethrough_origin,
326 glyph_origin.x - strikethrough_origin.x,
327 &strikethrough_style,
328 );
329 }
330
331 let max_glyph_bounds = Bounds {
332 origin: glyph_origin,
333 size: max_glyph_size,
334 };
335
336 let content_mask = window.content_mask();
337 if max_glyph_bounds.intersects(&content_mask.bounds) {
338 if glyph.is_emoji {
339 window.paint_emoji(
340 glyph_origin + baseline_offset,
341 run.font_id,
342 glyph.id,
343 layout.font_size,
344 )?;
345 } else {
346 window.paint_glyph(
347 glyph_origin + baseline_offset,
348 run.font_id,
349 glyph.id,
350 layout.font_size,
351 color,
352 )?;
353 }
354 }
355 }
356 }
357
358 let mut last_line_end_x = origin.x + layout.width;
359 if let Some(boundary) = wrap_boundaries.last() {
360 let run = &layout.runs[boundary.run_ix];
361 let glyph = &run.glyphs[boundary.glyph_ix];
362 last_line_end_x -= glyph.position.x;
363 }
364
365 if let Some((mut underline_start, underline_style)) = current_underline.take() {
366 if last_line_end_x == underline_start.x {
367 underline_start.x -= max_glyph_size.width.half()
368 };
369 window.paint_underline(
370 underline_start,
371 last_line_end_x - underline_start.x,
372 &underline_style,
373 );
374 }
375
376 if let Some((mut strikethrough_start, strikethrough_style)) = current_strikethrough.take() {
377 if last_line_end_x == strikethrough_start.x {
378 strikethrough_start.x -= max_glyph_size.width.half()
379 };
380 window.paint_strikethrough(
381 strikethrough_start,
382 last_line_end_x - strikethrough_start.x,
383 &strikethrough_style,
384 );
385 }
386
387 Ok(())
388 })
389}
390
391fn paint_line_background(
392 origin: Point<Pixels>,
393 layout: &LineLayout,
394 line_height: Pixels,
395 align: TextAlign,
396 align_width: Option<Pixels>,
397 decoration_runs: &[DecorationRun],
398 wrap_boundaries: &[WrapBoundary],
399 window: &mut Window,
400 cx: &mut App,
401) -> Result<()> {
402 let line_bounds = Bounds::new(
403 origin,
404 size(
405 layout.width,
406 line_height * (wrap_boundaries.len() as f32 + 1.),
407 ),
408 );
409 window.paint_layer(line_bounds, |window| {
410 let mut decoration_runs = decoration_runs.iter();
411 let mut wraps = wrap_boundaries.iter().peekable();
412 let mut run_end = 0;
413 let mut current_background: Option<(Point<Pixels>, Hsla)> = None;
414 let text_system = cx.text_system().clone();
415 let mut glyph_origin = point(
416 aligned_origin_x(
417 origin,
418 align_width.unwrap_or(layout.width),
419 px(0.0),
420 &align,
421 layout,
422 wraps.peek(),
423 ),
424 origin.y,
425 );
426 let mut prev_glyph_position = Point::default();
427 let mut max_glyph_size = size(px(0.), px(0.));
428 for (run_ix, run) in layout.runs.iter().enumerate() {
429 max_glyph_size = text_system.bounding_box(run.font_id, layout.font_size).size;
430
431 for (glyph_ix, glyph) in run.glyphs.iter().enumerate() {
432 glyph_origin.x += glyph.position.x - prev_glyph_position.x;
433
434 if wraps.peek() == Some(&&WrapBoundary { run_ix, glyph_ix }) {
435 wraps.next();
436 if let Some((background_origin, background_color)) = current_background.as_mut()
437 {
438 if glyph_origin.x == background_origin.x {
439 background_origin.x -= max_glyph_size.width.half()
440 }
441 window.paint_quad(fill(
442 Bounds {
443 origin: *background_origin,
444 size: size(glyph_origin.x - background_origin.x, line_height),
445 },
446 *background_color,
447 ));
448 background_origin.x = origin.x;
449 background_origin.y += line_height;
450 }
451 }
452 prev_glyph_position = glyph.position;
453
454 let mut finished_background: Option<(Point<Pixels>, Hsla)> = None;
455 if glyph.index >= run_end {
456 let mut style_run = decoration_runs.next();
457
458 // ignore style runs that apply to a partial glyph
459 while let Some(run) = style_run {
460 if glyph.index < run_end + (run.len as usize) {
461 break;
462 }
463 run_end += run.len as usize;
464 style_run = decoration_runs.next();
465 }
466
467 if let Some(style_run) = style_run {
468 if let Some((_, background_color)) = &mut current_background {
469 if style_run.background_color.as_ref() != Some(background_color) {
470 finished_background = current_background.take();
471 }
472 }
473 if let Some(run_background) = style_run.background_color {
474 current_background.get_or_insert((
475 point(glyph_origin.x, glyph_origin.y),
476 run_background,
477 ));
478 }
479 run_end += style_run.len as usize;
480 } else {
481 run_end = layout.len;
482 finished_background = current_background.take();
483 }
484 }
485
486 if let Some((mut background_origin, background_color)) = finished_background {
487 let mut width = glyph_origin.x - background_origin.x;
488 if background_origin.x == glyph_origin.x {
489 background_origin.x -= max_glyph_size.width.half();
490 };
491 window.paint_quad(fill(
492 Bounds {
493 origin: background_origin,
494 size: size(width, line_height),
495 },
496 background_color,
497 ));
498 }
499 }
500 }
501
502 let mut last_line_end_x = origin.x + layout.width;
503 if let Some(boundary) = wrap_boundaries.last() {
504 let run = &layout.runs[boundary.run_ix];
505 let glyph = &run.glyphs[boundary.glyph_ix];
506 last_line_end_x -= glyph.position.x;
507 }
508
509 if let Some((mut background_origin, background_color)) = current_background.take() {
510 if last_line_end_x == background_origin.x {
511 background_origin.x -= max_glyph_size.width.half()
512 };
513 window.paint_quad(fill(
514 Bounds {
515 origin: background_origin,
516 size: size(last_line_end_x - background_origin.x, line_height),
517 },
518 background_color,
519 ));
520 }
521
522 Ok(())
523 })
524}
525
526fn aligned_origin_x(
527 origin: Point<Pixels>,
528 align_width: Pixels,
529 last_glyph_x: Pixels,
530 align: &TextAlign,
531 layout: &LineLayout,
532 wrap_boundary: Option<&&WrapBoundary>,
533) -> Pixels {
534 let end_of_line = if let Some(WrapBoundary { run_ix, glyph_ix }) = wrap_boundary {
535 layout.runs[*run_ix].glyphs[*glyph_ix].position.x
536 } else {
537 layout.width
538 };
539
540 let line_width = end_of_line - last_glyph_x;
541
542 match align {
543 TextAlign::Left => origin.x,
544 TextAlign::Center => (2.0 * origin.x + align_width - line_width) / 2.0,
545 TextAlign::Right => origin.x + align_width - line_width,
546 }
547}