1use crate::{
2 point, px, size, Bounds, DevicePixels, Font, FontFeatures, FontId, FontMetrics, FontRun,
3 FontStyle, FontWeight, GlyphId, LineLayout, Pixels, PlatformTextSystem, Point,
4 RenderGlyphParams, Result, ShapedGlyph, ShapedRun, SharedString, Size, SUBPIXEL_VARIANTS,
5};
6use anyhow::anyhow;
7use cocoa::appkit::{CGFloat, CGPoint};
8use collections::{BTreeSet, HashMap};
9use core_foundation::{
10 array::CFIndex,
11 attributed_string::{CFAttributedStringRef, CFMutableAttributedString},
12 base::{CFRange, TCFType},
13 string::CFString,
14};
15use core_graphics::{
16 base::{kCGImageAlphaPremultipliedLast, CGGlyph},
17 color_space::CGColorSpace,
18 context::CGContext,
19};
20use core_text::{font::CTFont, line::CTLine, string_attributes::kCTFontAttributeName};
21use font_kit::{
22 font::Font as FontKitFont,
23 handle::Handle,
24 hinting::HintingOptions,
25 metrics::Metrics,
26 properties::{Style as FontkitStyle, Weight as FontkitWeight},
27 source::SystemSource,
28 sources::mem::MemSource,
29};
30use parking_lot::{RwLock, RwLockUpgradableReadGuard};
31use pathfinder_geometry::{
32 rect::{RectF, RectI},
33 transform2d::Transform2F,
34 vector::{Vector2F, Vector2I},
35};
36use smallvec::SmallVec;
37use std::{char, cmp, convert::TryFrom, ffi::c_void, sync::Arc};
38
39use super::open_type;
40
41#[allow(non_upper_case_globals)]
42const kCGImageAlphaOnly: u32 = 7;
43
44pub(crate) struct MacTextSystem(RwLock<MacTextSystemState>);
45
46struct MacTextSystemState {
47 memory_source: MemSource,
48 system_source: SystemSource,
49 fonts: Vec<FontKitFont>,
50 font_selections: HashMap<Font, FontId>,
51 font_ids_by_postscript_name: HashMap<String, FontId>,
52 font_ids_by_family_name: HashMap<SharedString, SmallVec<[FontId; 4]>>,
53 postscript_names_by_font_id: HashMap<FontId, String>,
54}
55
56impl MacTextSystem {
57 pub(crate) fn new() -> Self {
58 Self(RwLock::new(MacTextSystemState {
59 memory_source: MemSource::empty(),
60 system_source: SystemSource::new(),
61 fonts: Vec::new(),
62 font_selections: HashMap::default(),
63 font_ids_by_postscript_name: HashMap::default(),
64 font_ids_by_family_name: HashMap::default(),
65 postscript_names_by_font_id: HashMap::default(),
66 }))
67 }
68}
69
70impl Default for MacTextSystem {
71 fn default() -> Self {
72 Self::new()
73 }
74}
75
76impl PlatformTextSystem for MacTextSystem {
77 fn add_fonts(&self, fonts: &[Arc<Vec<u8>>]) -> Result<()> {
78 self.0.write().add_fonts(fonts)
79 }
80
81 fn all_font_names(&self) -> Vec<String> {
82 let collection = core_text::font_collection::create_for_all_families();
83 let Some(descriptors) = collection.get_descriptors() else {
84 return Vec::new();
85 };
86 let mut names = BTreeSet::new();
87 for descriptor in descriptors.into_iter() {
88 names.extend(lenient_font_attributes::family_name(&descriptor));
89 }
90 if let Ok(fonts_in_memory) = self.0.read().memory_source.all_families() {
91 names.extend(fonts_in_memory);
92 }
93 names.into_iter().collect()
94 }
95
96 fn all_font_families(&self) -> Vec<String> {
97 self.0
98 .read()
99 .system_source
100 .all_families()
101 .expect("core text should never return an error")
102 }
103
104 fn font_id(&self, font: &Font) -> Result<FontId> {
105 let lock = self.0.upgradable_read();
106 if let Some(font_id) = lock.font_selections.get(font) {
107 Ok(*font_id)
108 } else {
109 let mut lock = RwLockUpgradableReadGuard::upgrade(lock);
110 let candidates = if let Some(font_ids) = lock.font_ids_by_family_name.get(&font.family)
111 {
112 font_ids.as_slice()
113 } else {
114 let font_ids = lock.load_family(&font.family, font.features)?;
115 lock.font_ids_by_family_name
116 .insert(font.family.clone(), font_ids);
117 lock.font_ids_by_family_name[&font.family].as_ref()
118 };
119
120 let candidate_properties = candidates
121 .iter()
122 .map(|font_id| lock.fonts[font_id.0].properties())
123 .collect::<SmallVec<[_; 4]>>();
124
125 let ix = font_kit::matching::find_best_match(
126 &candidate_properties,
127 &font_kit::properties::Properties {
128 style: font.style.into(),
129 weight: font.weight.into(),
130 stretch: Default::default(),
131 },
132 )?;
133
134 let font_id = candidates[ix];
135 lock.font_selections.insert(font.clone(), font_id);
136 Ok(font_id)
137 }
138 }
139
140 fn font_metrics(&self, font_id: FontId) -> FontMetrics {
141 self.0.read().fonts[font_id.0].metrics().into()
142 }
143
144 fn typographic_bounds(&self, font_id: FontId, glyph_id: GlyphId) -> Result<Bounds<f32>> {
145 Ok(self.0.read().fonts[font_id.0]
146 .typographic_bounds(glyph_id.0)?
147 .into())
148 }
149
150 fn advance(&self, font_id: FontId, glyph_id: GlyphId) -> Result<Size<f32>> {
151 self.0.read().advance(font_id, glyph_id)
152 }
153
154 fn glyph_for_char(&self, font_id: FontId, ch: char) -> Option<GlyphId> {
155 self.0.read().glyph_for_char(font_id, ch)
156 }
157
158 fn glyph_raster_bounds(&self, params: &RenderGlyphParams) -> Result<Bounds<DevicePixels>> {
159 self.0.read().raster_bounds(params)
160 }
161
162 fn rasterize_glyph(
163 &self,
164 glyph_id: &RenderGlyphParams,
165 raster_bounds: Bounds<DevicePixels>,
166 ) -> Result<(Size<DevicePixels>, Vec<u8>)> {
167 self.0.read().rasterize_glyph(glyph_id, raster_bounds)
168 }
169
170 fn layout_line(&self, text: &str, font_size: Pixels, font_runs: &[FontRun]) -> LineLayout {
171 self.0.write().layout_line(text, font_size, font_runs)
172 }
173
174 fn wrap_line(
175 &self,
176 text: &str,
177 font_id: FontId,
178 font_size: Pixels,
179 width: Pixels,
180 ) -> Vec<usize> {
181 self.0.read().wrap_line(text, font_id, font_size, width)
182 }
183}
184
185impl MacTextSystemState {
186 fn add_fonts(&mut self, fonts: &[Arc<Vec<u8>>]) -> Result<()> {
187 self.memory_source.add_fonts(
188 fonts
189 .iter()
190 .map(|bytes| Handle::from_memory(bytes.clone(), 0)),
191 )?;
192 Ok(())
193 }
194
195 fn load_family(
196 &mut self,
197 name: &SharedString,
198 features: FontFeatures,
199 ) -> Result<SmallVec<[FontId; 4]>> {
200 let mut font_ids = SmallVec::new();
201 let family = self
202 .memory_source
203 .select_family_by_name(name.as_ref())
204 .or_else(|_| self.system_source.select_family_by_name(name.as_ref()))?;
205 for font in family.fonts() {
206 let mut font = font.load()?;
207 open_type::apply_features(&mut font, features);
208 let Some(_) = font.glyph_for_char('m') else {
209 continue;
210 };
211 let font_id = FontId(self.fonts.len());
212 font_ids.push(font_id);
213 let postscript_name = font.postscript_name().unwrap();
214 self.font_ids_by_postscript_name
215 .insert(postscript_name.clone(), font_id);
216 self.postscript_names_by_font_id
217 .insert(font_id, postscript_name);
218 self.fonts.push(font);
219 }
220 Ok(font_ids)
221 }
222
223 fn advance(&self, font_id: FontId, glyph_id: GlyphId) -> Result<Size<f32>> {
224 Ok(self.fonts[font_id.0].advance(glyph_id.0)?.into())
225 }
226
227 fn glyph_for_char(&self, font_id: FontId, ch: char) -> Option<GlyphId> {
228 self.fonts[font_id.0].glyph_for_char(ch).map(GlyphId)
229 }
230
231 fn id_for_native_font(&mut self, requested_font: CTFont) -> FontId {
232 let postscript_name = requested_font.postscript_name();
233 if let Some(font_id) = self.font_ids_by_postscript_name.get(&postscript_name) {
234 *font_id
235 } else {
236 let font_id = FontId(self.fonts.len());
237 self.font_ids_by_postscript_name
238 .insert(postscript_name.clone(), font_id);
239 self.postscript_names_by_font_id
240 .insert(font_id, postscript_name);
241 self.fonts
242 .push(font_kit::font::Font::from_core_graphics_font(
243 requested_font.copy_to_CGFont(),
244 ));
245 font_id
246 }
247 }
248
249 fn is_emoji(&self, font_id: FontId) -> bool {
250 self.postscript_names_by_font_id
251 .get(&font_id)
252 .map_or(false, |postscript_name| {
253 postscript_name == "AppleColorEmoji"
254 })
255 }
256
257 fn raster_bounds(&self, params: &RenderGlyphParams) -> Result<Bounds<DevicePixels>> {
258 let font = &self.fonts[params.font_id.0];
259 let scale = Transform2F::from_scale(params.scale_factor);
260 Ok(font
261 .raster_bounds(
262 params.glyph_id.0,
263 params.font_size.into(),
264 scale,
265 HintingOptions::None,
266 font_kit::canvas::RasterizationOptions::GrayscaleAa,
267 )?
268 .into())
269 }
270
271 fn rasterize_glyph(
272 &self,
273 params: &RenderGlyphParams,
274 glyph_bounds: Bounds<DevicePixels>,
275 ) -> Result<(Size<DevicePixels>, Vec<u8>)> {
276 if glyph_bounds.size.width.0 == 0 || glyph_bounds.size.height.0 == 0 {
277 Err(anyhow!("glyph bounds are empty"))
278 } else {
279 // Add an extra pixel when the subpixel variant isn't zero to make room for anti-aliasing.
280 let mut bitmap_size = glyph_bounds.size;
281 if params.subpixel_variant.x > 0 {
282 bitmap_size.width += DevicePixels(1);
283 }
284 if params.subpixel_variant.y > 0 {
285 bitmap_size.height += DevicePixels(1);
286 }
287 let bitmap_size = bitmap_size;
288
289 let mut bytes;
290 let cx;
291 if params.is_emoji {
292 bytes = vec![0; bitmap_size.width.0 as usize * 4 * bitmap_size.height.0 as usize];
293 cx = CGContext::create_bitmap_context(
294 Some(bytes.as_mut_ptr() as *mut _),
295 bitmap_size.width.0 as usize,
296 bitmap_size.height.0 as usize,
297 8,
298 bitmap_size.width.0 as usize * 4,
299 &CGColorSpace::create_device_rgb(),
300 kCGImageAlphaPremultipliedLast,
301 );
302 } else {
303 bytes = vec![0; bitmap_size.width.0 as usize * bitmap_size.height.0 as usize];
304 cx = CGContext::create_bitmap_context(
305 Some(bytes.as_mut_ptr() as *mut _),
306 bitmap_size.width.0 as usize,
307 bitmap_size.height.0 as usize,
308 8,
309 bitmap_size.width.0 as usize,
310 &CGColorSpace::create_device_gray(),
311 kCGImageAlphaOnly,
312 );
313 }
314
315 // Move the origin to bottom left and account for scaling, this
316 // makes drawing text consistent with the font-kit's raster_bounds.
317 cx.translate(
318 -glyph_bounds.origin.x.0 as CGFloat,
319 (glyph_bounds.origin.y.0 + glyph_bounds.size.height.0) as CGFloat,
320 );
321 cx.scale(
322 params.scale_factor as CGFloat,
323 params.scale_factor as CGFloat,
324 );
325
326 let subpixel_shift = params
327 .subpixel_variant
328 .map(|v| v as f32 / SUBPIXEL_VARIANTS as f32);
329 cx.set_allows_font_subpixel_positioning(true);
330 cx.set_should_subpixel_position_fonts(true);
331 cx.set_allows_font_subpixel_quantization(false);
332 cx.set_should_subpixel_quantize_fonts(false);
333 self.fonts[params.font_id.0]
334 .native_font()
335 .clone_with_font_size(f32::from(params.font_size) as CGFloat)
336 .draw_glyphs(
337 &[params.glyph_id.0 as CGGlyph],
338 &[CGPoint::new(
339 (subpixel_shift.x / params.scale_factor) as CGFloat,
340 (subpixel_shift.y / params.scale_factor) as CGFloat,
341 )],
342 cx,
343 );
344
345 if params.is_emoji {
346 // Convert from RGBA with premultiplied alpha to BGRA with straight alpha.
347 for pixel in bytes.chunks_exact_mut(4) {
348 pixel.swap(0, 2);
349 let a = pixel[3] as f32 / 255.;
350 pixel[0] = (pixel[0] as f32 / a) as u8;
351 pixel[1] = (pixel[1] as f32 / a) as u8;
352 pixel[2] = (pixel[2] as f32 / a) as u8;
353 }
354 }
355
356 Ok((bitmap_size, bytes))
357 }
358 }
359
360 fn layout_line(&mut self, text: &str, font_size: Pixels, font_runs: &[FontRun]) -> LineLayout {
361 // Construct the attributed string, converting UTF8 ranges to UTF16 ranges.
362 let mut string = CFMutableAttributedString::new();
363 {
364 string.replace_str(&CFString::new(text), CFRange::init(0, 0));
365 let utf16_line_len = string.char_len() as usize;
366
367 let mut ix_converter = StringIndexConverter::new(text);
368 for run in font_runs {
369 let utf8_end = ix_converter.utf8_ix + run.len;
370 let utf16_start = ix_converter.utf16_ix;
371
372 if utf16_start >= utf16_line_len {
373 break;
374 }
375
376 ix_converter.advance_to_utf8_ix(utf8_end);
377 let utf16_end = cmp::min(ix_converter.utf16_ix, utf16_line_len);
378
379 let cf_range =
380 CFRange::init(utf16_start as isize, (utf16_end - utf16_start) as isize);
381
382 let font: &FontKitFont = &self.fonts[run.font_id.0];
383 unsafe {
384 string.set_attribute(
385 cf_range,
386 kCTFontAttributeName,
387 &font.native_font().clone_with_font_size(font_size.into()),
388 );
389 }
390
391 if utf16_end == utf16_line_len {
392 break;
393 }
394 }
395 }
396
397 // Retrieve the glyphs from the shaped line, converting UTF16 offsets to UTF8 offsets.
398 let line = CTLine::new_with_attributed_string(string.as_concrete_TypeRef());
399
400 let mut runs = Vec::new();
401 for run in line.glyph_runs().into_iter() {
402 let attributes = run.attributes().unwrap();
403 let font = unsafe {
404 attributes
405 .get(kCTFontAttributeName)
406 .downcast::<CTFont>()
407 .unwrap()
408 };
409 let font_id = self.id_for_native_font(font);
410
411 let mut ix_converter = StringIndexConverter::new(text);
412 let mut glyphs = SmallVec::new();
413 for ((glyph_id, position), glyph_utf16_ix) in run
414 .glyphs()
415 .iter()
416 .zip(run.positions().iter())
417 .zip(run.string_indices().iter())
418 {
419 let glyph_utf16_ix = usize::try_from(*glyph_utf16_ix).unwrap();
420 ix_converter.advance_to_utf16_ix(glyph_utf16_ix);
421 glyphs.push(ShapedGlyph {
422 id: GlyphId(*glyph_id as u32),
423 position: point(position.x as f32, position.y as f32).map(px),
424 index: ix_converter.utf8_ix,
425 is_emoji: self.is_emoji(font_id),
426 });
427 }
428
429 runs.push(ShapedRun { font_id, glyphs })
430 }
431
432 let typographic_bounds = line.get_typographic_bounds();
433 LineLayout {
434 runs,
435 font_size,
436 width: typographic_bounds.width.into(),
437 ascent: typographic_bounds.ascent.into(),
438 descent: typographic_bounds.descent.into(),
439 len: text.len(),
440 }
441 }
442
443 fn wrap_line(
444 &self,
445 text: &str,
446 font_id: FontId,
447 font_size: Pixels,
448 width: Pixels,
449 ) -> Vec<usize> {
450 let mut string = CFMutableAttributedString::new();
451 string.replace_str(&CFString::new(text), CFRange::init(0, 0));
452 let cf_range = CFRange::init(0, text.encode_utf16().count() as isize);
453 let font = &self.fonts[font_id.0];
454 unsafe {
455 string.set_attribute(
456 cf_range,
457 kCTFontAttributeName,
458 &font.native_font().clone_with_font_size(font_size.into()),
459 );
460
461 let typesetter = CTTypesetterCreateWithAttributedString(string.as_concrete_TypeRef());
462 let mut ix_converter = StringIndexConverter::new(text);
463 let mut break_indices = Vec::new();
464 while ix_converter.utf8_ix < text.len() {
465 let utf16_len = CTTypesetterSuggestLineBreak(
466 typesetter,
467 ix_converter.utf16_ix as isize,
468 width.into(),
469 ) as usize;
470 ix_converter.advance_to_utf16_ix(ix_converter.utf16_ix + utf16_len);
471 if ix_converter.utf8_ix >= text.len() {
472 break;
473 }
474 break_indices.push(ix_converter.utf8_ix);
475 }
476 break_indices
477 }
478 }
479}
480
481#[derive(Clone)]
482struct StringIndexConverter<'a> {
483 text: &'a str,
484 utf8_ix: usize,
485 utf16_ix: usize,
486}
487
488impl<'a> StringIndexConverter<'a> {
489 fn new(text: &'a str) -> Self {
490 Self {
491 text,
492 utf8_ix: 0,
493 utf16_ix: 0,
494 }
495 }
496
497 fn advance_to_utf8_ix(&mut self, utf8_target: usize) {
498 for (ix, c) in self.text[self.utf8_ix..].char_indices() {
499 if self.utf8_ix + ix >= utf8_target {
500 self.utf8_ix += ix;
501 return;
502 }
503 self.utf16_ix += c.len_utf16();
504 }
505 self.utf8_ix = self.text.len();
506 }
507
508 fn advance_to_utf16_ix(&mut self, utf16_target: usize) {
509 for (ix, c) in self.text[self.utf8_ix..].char_indices() {
510 if self.utf16_ix >= utf16_target {
511 self.utf8_ix += ix;
512 return;
513 }
514 self.utf16_ix += c.len_utf16();
515 }
516 self.utf8_ix = self.text.len();
517 }
518}
519
520#[repr(C)]
521pub(crate) struct __CFTypesetter(c_void);
522
523type CTTypesetterRef = *const __CFTypesetter;
524
525#[link(name = "CoreText", kind = "framework")]
526extern "C" {
527 fn CTTypesetterCreateWithAttributedString(string: CFAttributedStringRef) -> CTTypesetterRef;
528
529 fn CTTypesetterSuggestLineBreak(
530 typesetter: CTTypesetterRef,
531 start_index: CFIndex,
532 width: f64,
533 ) -> CFIndex;
534}
535
536impl From<Metrics> for FontMetrics {
537 fn from(metrics: Metrics) -> Self {
538 FontMetrics {
539 units_per_em: metrics.units_per_em,
540 ascent: metrics.ascent,
541 descent: metrics.descent,
542 line_gap: metrics.line_gap,
543 underline_position: metrics.underline_position,
544 underline_thickness: metrics.underline_thickness,
545 cap_height: metrics.cap_height,
546 x_height: metrics.x_height,
547 bounding_box: metrics.bounding_box.into(),
548 }
549 }
550}
551
552impl From<RectF> for Bounds<f32> {
553 fn from(rect: RectF) -> Self {
554 Bounds {
555 origin: point(rect.origin_x(), rect.origin_y()),
556 size: size(rect.width(), rect.height()),
557 }
558 }
559}
560
561impl From<RectI> for Bounds<DevicePixels> {
562 fn from(rect: RectI) -> Self {
563 Bounds {
564 origin: point(DevicePixels(rect.origin_x()), DevicePixels(rect.origin_y())),
565 size: size(DevicePixels(rect.width()), DevicePixels(rect.height())),
566 }
567 }
568}
569
570impl From<Vector2I> for Size<DevicePixels> {
571 fn from(value: Vector2I) -> Self {
572 size(value.x().into(), value.y().into())
573 }
574}
575
576impl From<RectI> for Bounds<i32> {
577 fn from(rect: RectI) -> Self {
578 Bounds {
579 origin: point(rect.origin_x(), rect.origin_y()),
580 size: size(rect.width(), rect.height()),
581 }
582 }
583}
584
585impl From<Point<u32>> for Vector2I {
586 fn from(size: Point<u32>) -> Self {
587 Vector2I::new(size.x as i32, size.y as i32)
588 }
589}
590
591impl From<Vector2F> for Size<f32> {
592 fn from(vec: Vector2F) -> Self {
593 size(vec.x(), vec.y())
594 }
595}
596
597impl From<FontWeight> for FontkitWeight {
598 fn from(value: FontWeight) -> Self {
599 FontkitWeight(value.0)
600 }
601}
602
603impl From<FontStyle> for FontkitStyle {
604 fn from(style: FontStyle) -> Self {
605 match style {
606 FontStyle::Normal => FontkitStyle::Normal,
607 FontStyle::Italic => FontkitStyle::Italic,
608 FontStyle::Oblique => FontkitStyle::Oblique,
609 }
610 }
611}
612
613// Some fonts may have no attributest despite `core_text` requiring them (and panicking).
614// This is the same version as `core_text` has without `expect` calls.
615mod lenient_font_attributes {
616 use core_foundation::{
617 base::{CFRetain, CFType, TCFType},
618 string::{CFString, CFStringRef},
619 };
620 use core_text::font_descriptor::{
621 kCTFontFamilyNameAttribute, CTFontDescriptor, CTFontDescriptorCopyAttribute,
622 };
623
624 pub fn family_name(descriptor: &CTFontDescriptor) -> Option<String> {
625 unsafe { get_string_attribute(descriptor, kCTFontFamilyNameAttribute) }
626 }
627
628 fn get_string_attribute(
629 descriptor: &CTFontDescriptor,
630 attribute: CFStringRef,
631 ) -> Option<String> {
632 unsafe {
633 let value = CTFontDescriptorCopyAttribute(descriptor.as_concrete_TypeRef(), attribute);
634 if value.is_null() {
635 return None;
636 }
637
638 let value = CFType::wrap_under_create_rule(value);
639 assert!(value.instance_of::<CFString>());
640 let s = wrap_under_get_rule(value.as_CFTypeRef() as CFStringRef);
641 Some(s.to_string())
642 }
643 }
644
645 unsafe fn wrap_under_get_rule(reference: CFStringRef) -> CFString {
646 assert!(!reference.is_null(), "Attempted to create a NULL object.");
647 let reference = CFRetain(reference as *const ::std::os::raw::c_void) as CFStringRef;
648 TCFType::wrap_under_create_rule(reference)
649 }
650}
651
652#[cfg(test)]
653mod tests {
654 use crate::{font, px, FontRun, GlyphId, MacTextSystem, PlatformTextSystem};
655
656 #[test]
657 fn test_wrap_line() {
658 let fonts = MacTextSystem::new();
659 let font_id = fonts.font_id(&font("Helvetica")).unwrap();
660
661 let line = "one two three four five\n";
662 let wrap_boundaries = fonts.wrap_line(line, font_id, px(16.), px(64.0));
663 assert_eq!(wrap_boundaries, &["one two ".len(), "one two three ".len()]);
664
665 let line = "aaa ααα ✋✋✋ 🎉🎉🎉\n";
666 let wrap_boundaries = fonts.wrap_line(line, font_id, px(16.), px(64.0));
667 assert_eq!(
668 wrap_boundaries,
669 &["aaa ααα ".len(), "aaa ααα ✋✋✋ ".len(),]
670 );
671 }
672
673 #[test]
674 fn test_layout_line_bom_char() {
675 let fonts = MacTextSystem::new();
676 let font_id = fonts.font_id(&font("Helvetica")).unwrap();
677 let line = "\u{feff}";
678 let mut style = FontRun {
679 font_id,
680 len: line.len(),
681 };
682
683 let layout = fonts.layout_line(line, px(16.), &[style]);
684 assert_eq!(layout.len, line.len());
685 assert!(layout.runs.is_empty());
686
687 let line = "a\u{feff}b";
688 style.len = line.len();
689 let layout = fonts.layout_line(line, px(16.), &[style]);
690 assert_eq!(layout.len, line.len());
691 assert_eq!(layout.runs.len(), 1);
692 assert_eq!(layout.runs[0].glyphs.len(), 2);
693 assert_eq!(layout.runs[0].glyphs[0].id, GlyphId(68u32)); // a
694 // There's no glyph for \u{feff}
695 assert_eq!(layout.runs[0].glyphs[1].id, GlyphId(69u32)); // b
696 }
697}