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
86/// A line of text that has been shaped, decorated, and wrapped by the text layout system.
87#[derive(Clone, Default, Debug, Deref, DerefMut)]
88pub struct WrappedLine {
89 #[deref]
90 #[deref_mut]
91 pub(crate) layout: Arc<WrappedLineLayout>,
92 /// The text that was shaped for this line.
93 pub text: SharedString,
94 pub(crate) decoration_runs: SmallVec<[DecorationRun; 32]>,
95}
96
97impl WrappedLine {
98 /// The length of the underlying, unwrapped layout, in utf-8 bytes.
99 #[allow(clippy::len_without_is_empty)]
100 pub fn len(&self) -> usize {
101 self.layout.len()
102 }
103
104 /// Paint this line of text to the window.
105 pub fn paint(
106 &self,
107 origin: Point<Pixels>,
108 line_height: Pixels,
109 align: TextAlign,
110 bounds: Option<Bounds<Pixels>>,
111 window: &mut Window,
112 cx: &mut App,
113 ) -> Result<()> {
114 let align_width = match bounds {
115 Some(bounds) => Some(bounds.size.width),
116 None => self.layout.wrap_width,
117 };
118
119 paint_line(
120 origin,
121 &self.layout.unwrapped_layout,
122 line_height,
123 align,
124 align_width,
125 &self.decoration_runs,
126 &self.wrap_boundaries,
127 window,
128 cx,
129 )?;
130
131 Ok(())
132 }
133}
134
135fn paint_line(
136 origin: Point<Pixels>,
137 layout: &LineLayout,
138 line_height: Pixels,
139 align: TextAlign,
140 align_width: Option<Pixels>,
141 decoration_runs: &[DecorationRun],
142 wrap_boundaries: &[WrapBoundary],
143 window: &mut Window,
144 cx: &mut App,
145) -> Result<()> {
146 let line_bounds = Bounds::new(
147 origin,
148 size(
149 layout.width,
150 line_height * (wrap_boundaries.len() as f32 + 1.),
151 ),
152 );
153 window.paint_layer(line_bounds, |window| {
154 let padding_top = (line_height - layout.ascent - layout.descent) / 2.;
155 let baseline_offset = point(px(0.), padding_top + layout.ascent);
156 let mut decoration_runs = decoration_runs.iter();
157 let mut wraps = wrap_boundaries.iter().peekable();
158 let mut run_end = 0;
159 let mut color = black();
160 let mut current_underline: Option<(Point<Pixels>, UnderlineStyle)> = None;
161 let mut current_strikethrough: Option<(Point<Pixels>, StrikethroughStyle)> = None;
162 let mut current_background: Option<(Point<Pixels>, Hsla)> = None;
163 let text_system = cx.text_system().clone();
164 let mut glyph_origin = point(
165 aligned_origin_x(
166 origin,
167 align_width.unwrap_or(layout.width),
168 px(0.0),
169 &align,
170 layout,
171 wraps.peek(),
172 ),
173 origin.y,
174 );
175 let mut prev_glyph_position = Point::default();
176 let mut max_glyph_size = size(px(0.), px(0.));
177 for (run_ix, run) in layout.runs.iter().enumerate() {
178 max_glyph_size = text_system.bounding_box(run.font_id, layout.font_size).size;
179
180 for (glyph_ix, glyph) in run.glyphs.iter().enumerate() {
181 glyph_origin.x += glyph.position.x - prev_glyph_position.x;
182
183 if wraps.peek() == Some(&&WrapBoundary { run_ix, glyph_ix }) {
184 wraps.next();
185 if let Some((background_origin, background_color)) = current_background.as_mut()
186 {
187 if glyph_origin.x == background_origin.x {
188 background_origin.x -= max_glyph_size.width.half()
189 }
190 window.paint_quad(fill(
191 Bounds {
192 origin: *background_origin,
193 size: size(glyph_origin.x - background_origin.x, line_height),
194 },
195 *background_color,
196 ));
197 background_origin.x = origin.x;
198 background_origin.y += line_height;
199 }
200 if let Some((underline_origin, underline_style)) = current_underline.as_mut() {
201 if glyph_origin.x == underline_origin.x {
202 underline_origin.x -= max_glyph_size.width.half();
203 };
204 window.paint_underline(
205 *underline_origin,
206 glyph_origin.x - underline_origin.x,
207 underline_style,
208 );
209 underline_origin.x = origin.x;
210 underline_origin.y += line_height;
211 }
212 if let Some((strikethrough_origin, strikethrough_style)) =
213 current_strikethrough.as_mut()
214 {
215 if glyph_origin.x == strikethrough_origin.x {
216 strikethrough_origin.x -= max_glyph_size.width.half();
217 };
218 window.paint_strikethrough(
219 *strikethrough_origin,
220 glyph_origin.x - strikethrough_origin.x,
221 strikethrough_style,
222 );
223 strikethrough_origin.x = origin.x;
224 strikethrough_origin.y += line_height;
225 }
226
227 glyph_origin.x = aligned_origin_x(
228 origin,
229 align_width.unwrap_or(layout.width),
230 glyph.position.x,
231 &align,
232 layout,
233 wraps.peek(),
234 );
235 glyph_origin.y += line_height;
236 }
237 prev_glyph_position = glyph.position;
238
239 let mut finished_background: Option<(Point<Pixels>, Hsla)> = None;
240 let mut finished_underline: Option<(Point<Pixels>, UnderlineStyle)> = None;
241 let mut finished_strikethrough: Option<(Point<Pixels>, StrikethroughStyle)> = None;
242 if glyph.index >= run_end {
243 let mut style_run = decoration_runs.next();
244
245 // ignore style runs that apply to a partial glyph
246 while let Some(run) = style_run {
247 if glyph.index < run_end + (run.len as usize) {
248 break;
249 }
250 run_end += run.len as usize;
251 style_run = decoration_runs.next();
252 }
253
254 if let Some(style_run) = style_run {
255 if let Some((_, background_color)) = &mut current_background {
256 if style_run.background_color.as_ref() != Some(background_color) {
257 finished_background = current_background.take();
258 }
259 }
260 if let Some(run_background) = style_run.background_color {
261 current_background.get_or_insert((
262 point(glyph_origin.x, glyph_origin.y),
263 run_background,
264 ));
265 }
266
267 if let Some((_, underline_style)) = &mut current_underline {
268 if style_run.underline.as_ref() != Some(underline_style) {
269 finished_underline = current_underline.take();
270 }
271 }
272 if let Some(run_underline) = style_run.underline.as_ref() {
273 current_underline.get_or_insert((
274 point(
275 glyph_origin.x,
276 glyph_origin.y + baseline_offset.y + (layout.descent * 0.618),
277 ),
278 UnderlineStyle {
279 color: Some(run_underline.color.unwrap_or(style_run.color)),
280 thickness: run_underline.thickness,
281 wavy: run_underline.wavy,
282 },
283 ));
284 }
285 if let Some((_, strikethrough_style)) = &mut current_strikethrough {
286 if style_run.strikethrough.as_ref() != Some(strikethrough_style) {
287 finished_strikethrough = current_strikethrough.take();
288 }
289 }
290 if let Some(run_strikethrough) = style_run.strikethrough.as_ref() {
291 current_strikethrough.get_or_insert((
292 point(
293 glyph_origin.x,
294 glyph_origin.y
295 + (((layout.ascent * 0.5) + baseline_offset.y) * 0.5),
296 ),
297 StrikethroughStyle {
298 color: Some(run_strikethrough.color.unwrap_or(style_run.color)),
299 thickness: run_strikethrough.thickness,
300 },
301 ));
302 }
303
304 run_end += style_run.len as usize;
305 color = style_run.color;
306 } else {
307 run_end = layout.len;
308 finished_background = current_background.take();
309 finished_underline = current_underline.take();
310 finished_strikethrough = current_strikethrough.take();
311 }
312 }
313
314 if let Some((mut background_origin, background_color)) = finished_background {
315 let mut width = glyph_origin.x - background_origin.x;
316 if background_origin.x == glyph_origin.x {
317 background_origin.x -= max_glyph_size.width.half();
318 };
319 window.paint_quad(fill(
320 Bounds {
321 origin: background_origin,
322 size: size(width, line_height),
323 },
324 background_color,
325 ));
326 }
327
328 if let Some((mut underline_origin, underline_style)) = finished_underline {
329 if underline_origin.x == glyph_origin.x {
330 underline_origin.x -= max_glyph_size.width.half();
331 };
332 window.paint_underline(
333 underline_origin,
334 glyph_origin.x - underline_origin.x,
335 &underline_style,
336 );
337 }
338
339 if let Some((mut strikethrough_origin, strikethrough_style)) =
340 finished_strikethrough
341 {
342 if strikethrough_origin.x == glyph_origin.x {
343 strikethrough_origin.x -= max_glyph_size.width.half();
344 };
345 window.paint_strikethrough(
346 strikethrough_origin,
347 glyph_origin.x - strikethrough_origin.x,
348 &strikethrough_style,
349 );
350 }
351
352 let max_glyph_bounds = Bounds {
353 origin: glyph_origin,
354 size: max_glyph_size,
355 };
356
357 let content_mask = window.content_mask();
358 if max_glyph_bounds.intersects(&content_mask.bounds) {
359 if glyph.is_emoji {
360 window.paint_emoji(
361 glyph_origin + baseline_offset,
362 run.font_id,
363 glyph.id,
364 layout.font_size,
365 )?;
366 } else {
367 window.paint_glyph(
368 glyph_origin + baseline_offset,
369 run.font_id,
370 glyph.id,
371 layout.font_size,
372 color,
373 )?;
374 }
375 }
376 }
377 }
378
379 let mut last_line_end_x = origin.x + layout.width;
380 if let Some(boundary) = wrap_boundaries.last() {
381 let run = &layout.runs[boundary.run_ix];
382 let glyph = &run.glyphs[boundary.glyph_ix];
383 last_line_end_x -= glyph.position.x;
384 }
385
386 if let Some((mut background_origin, background_color)) = current_background.take() {
387 if last_line_end_x == background_origin.x {
388 background_origin.x -= max_glyph_size.width.half()
389 };
390 window.paint_quad(fill(
391 Bounds {
392 origin: background_origin,
393 size: size(last_line_end_x - background_origin.x, line_height),
394 },
395 background_color,
396 ));
397 }
398
399 if let Some((mut underline_start, underline_style)) = current_underline.take() {
400 if last_line_end_x == underline_start.x {
401 underline_start.x -= max_glyph_size.width.half()
402 };
403 window.paint_underline(
404 underline_start,
405 last_line_end_x - underline_start.x,
406 &underline_style,
407 );
408 }
409
410 if let Some((mut strikethrough_start, strikethrough_style)) = current_strikethrough.take() {
411 if last_line_end_x == strikethrough_start.x {
412 strikethrough_start.x -= max_glyph_size.width.half()
413 };
414 window.paint_strikethrough(
415 strikethrough_start,
416 last_line_end_x - strikethrough_start.x,
417 &strikethrough_style,
418 );
419 }
420
421 Ok(())
422 })
423}
424
425fn aligned_origin_x(
426 origin: Point<Pixels>,
427 align_width: Pixels,
428 last_glyph_x: Pixels,
429 align: &TextAlign,
430 layout: &LineLayout,
431 wrap_boundary: Option<&&WrapBoundary>,
432) -> Pixels {
433 let end_of_line = if let Some(WrapBoundary { run_ix, glyph_ix }) = wrap_boundary {
434 layout.runs[*run_ix].glyphs[*glyph_ix].position.x
435 } else {
436 layout.width
437 };
438
439 let line_width = end_of_line - last_glyph_x;
440
441 match align {
442 TextAlign::Left => origin.x,
443 TextAlign::Center => (2.0 * origin.x + align_width - line_width) / 2.0,
444 TextAlign::Right => origin.x + align_width - line_width,
445 }
446}