1use crate::{
2 point, px, size, Bounds, DevicePixels, Font, FontFallbacks, FontFeatures, FontId, FontMetrics,
3 FontRun, FontStyle, FontWeight, GlyphId, LineLayout, Pixels, PlatformTextSystem, Point,
4 RenderGlyphParams, Result, ShapedGlyph, ShapedRun, SharedString, Size, SUBPIXEL_VARIANTS,
5};
6use anyhow::anyhow;
7use cocoa::appkit::CGFloat;
8use collections::HashMap;
9use core_foundation::{
10 attributed_string::CFMutableAttributedString,
11 base::{CFRange, TCFType},
12 number::CFNumber,
13 string::CFString,
14};
15use core_graphics::{
16 base::{kCGImageAlphaPremultipliedLast, CGGlyph},
17 color_space::CGColorSpace,
18 context::CGContext,
19 display::CGPoint,
20};
21use core_text::{
22 font::CTFont,
23 font_descriptor::{
24 kCTFontSlantTrait, kCTFontSymbolicTrait, kCTFontWeightTrait, kCTFontWidthTrait,
25 },
26 line::CTLine,
27 string_attributes::kCTFontAttributeName,
28};
29use font_kit::{
30 font::Font as FontKitFont,
31 handle::Handle,
32 hinting::HintingOptions,
33 metrics::Metrics,
34 properties::{Style as FontkitStyle, Weight as FontkitWeight},
35 source::SystemSource,
36 sources::mem::MemSource,
37};
38use parking_lot::{RwLock, RwLockUpgradableReadGuard};
39use pathfinder_geometry::{
40 rect::{RectF, RectI},
41 transform2d::Transform2F,
42 vector::{Vector2F, Vector2I},
43};
44use smallvec::SmallVec;
45use std::{borrow::Cow, char, cmp, convert::TryFrom, sync::Arc};
46
47use super::open_type::apply_features_and_fallbacks;
48
49#[allow(non_upper_case_globals)]
50const kCGImageAlphaOnly: u32 = 7;
51
52pub(crate) struct MacTextSystem(RwLock<MacTextSystemState>);
53
54#[derive(Clone, PartialEq, Eq, Hash)]
55struct FontKey {
56 font_family: SharedString,
57 font_features: FontFeatures,
58 font_fallbacks: Option<FontFallbacks>,
59}
60
61struct MacTextSystemState {
62 memory_source: MemSource,
63 system_source: SystemSource,
64 fonts: Vec<FontKitFont>,
65 font_selections: HashMap<Font, FontId>,
66 font_ids_by_postscript_name: HashMap<String, FontId>,
67 font_ids_by_font_key: HashMap<FontKey, SmallVec<[FontId; 4]>>,
68 postscript_names_by_font_id: HashMap<FontId, String>,
69}
70
71impl MacTextSystem {
72 pub(crate) fn new() -> Self {
73 Self(RwLock::new(MacTextSystemState {
74 memory_source: MemSource::empty(),
75 system_source: SystemSource::new(),
76 fonts: Vec::new(),
77 font_selections: HashMap::default(),
78 font_ids_by_postscript_name: HashMap::default(),
79 font_ids_by_font_key: HashMap::default(),
80 postscript_names_by_font_id: HashMap::default(),
81 }))
82 }
83}
84
85impl Default for MacTextSystem {
86 fn default() -> Self {
87 Self::new()
88 }
89}
90
91impl PlatformTextSystem for MacTextSystem {
92 fn add_fonts(&self, fonts: Vec<Cow<'static, [u8]>>) -> Result<()> {
93 self.0.write().add_fonts(fonts)
94 }
95
96 fn all_font_names(&self) -> Vec<String> {
97 let mut names = Vec::new();
98 let collection = core_text::font_collection::create_for_all_families();
99 let Some(descriptors) = collection.get_descriptors() else {
100 return names;
101 };
102 for descriptor in descriptors.into_iter() {
103 names.extend(lenient_font_attributes::family_name(&descriptor));
104 }
105 if let Ok(fonts_in_memory) = self.0.read().memory_source.all_families() {
106 names.extend(fonts_in_memory);
107 }
108 names
109 }
110
111 fn font_id(&self, font: &Font) -> Result<FontId> {
112 let lock = self.0.upgradable_read();
113 if let Some(font_id) = lock.font_selections.get(font) {
114 Ok(*font_id)
115 } else {
116 let mut lock = RwLockUpgradableReadGuard::upgrade(lock);
117 let font_key = FontKey {
118 font_family: font.family.clone(),
119 font_features: font.features.clone(),
120 font_fallbacks: font.fallbacks.clone(),
121 };
122 let candidates = if let Some(font_ids) = lock.font_ids_by_font_key.get(&font_key) {
123 font_ids.as_slice()
124 } else {
125 let font_ids =
126 lock.load_family(&font.family, &font.features, font.fallbacks.as_ref())?;
127 lock.font_ids_by_font_key.insert(font_key.clone(), font_ids);
128 lock.font_ids_by_font_key[&font_key].as_ref()
129 };
130
131 let candidate_properties = candidates
132 .iter()
133 .map(|font_id| lock.fonts[font_id.0].properties())
134 .collect::<SmallVec<[_; 4]>>();
135
136 let ix = font_kit::matching::find_best_match(
137 &candidate_properties,
138 &font_kit::properties::Properties {
139 style: font.style.into(),
140 weight: font.weight.into(),
141 stretch: Default::default(),
142 },
143 )?;
144
145 let font_id = candidates[ix];
146 lock.font_selections.insert(font.clone(), font_id);
147 Ok(font_id)
148 }
149 }
150
151 fn font_metrics(&self, font_id: FontId) -> FontMetrics {
152 self.0.read().fonts[font_id.0].metrics().into()
153 }
154
155 fn typographic_bounds(&self, font_id: FontId, glyph_id: GlyphId) -> Result<Bounds<f32>> {
156 Ok(self.0.read().fonts[font_id.0]
157 .typographic_bounds(glyph_id.0)?
158 .into())
159 }
160
161 fn advance(&self, font_id: FontId, glyph_id: GlyphId) -> Result<Size<f32>> {
162 self.0.read().advance(font_id, glyph_id)
163 }
164
165 fn glyph_for_char(&self, font_id: FontId, ch: char) -> Option<GlyphId> {
166 self.0.read().glyph_for_char(font_id, ch)
167 }
168
169 fn glyph_raster_bounds(&self, params: &RenderGlyphParams) -> Result<Bounds<DevicePixels>> {
170 self.0.read().raster_bounds(params)
171 }
172
173 fn rasterize_glyph(
174 &self,
175 glyph_id: &RenderGlyphParams,
176 raster_bounds: Bounds<DevicePixels>,
177 ) -> Result<(Size<DevicePixels>, Vec<u8>)> {
178 self.0.read().rasterize_glyph(glyph_id, raster_bounds)
179 }
180
181 fn layout_line(&self, text: &str, font_size: Pixels, font_runs: &[FontRun]) -> LineLayout {
182 self.0.write().layout_line(text, font_size, font_runs)
183 }
184}
185
186impl MacTextSystemState {
187 fn add_fonts(&mut self, fonts: Vec<Cow<'static, [u8]>>) -> Result<()> {
188 let fonts = fonts
189 .into_iter()
190 .map(|bytes| match bytes {
191 Cow::Borrowed(embedded_font) => {
192 let data_provider = unsafe {
193 core_graphics::data_provider::CGDataProvider::from_slice(embedded_font)
194 };
195 let font = core_graphics::font::CGFont::from_data_provider(data_provider)
196 .map_err(|_| anyhow!("Could not load an embedded font."))?;
197 let font = font_kit::loaders::core_text::Font::from_core_graphics_font(font);
198 Ok(Handle::from_native(&font))
199 }
200 Cow::Owned(bytes) => Ok(Handle::from_memory(Arc::new(bytes), 0)),
201 })
202 .collect::<Result<Vec<_>>>()?;
203 self.memory_source.add_fonts(fonts.into_iter())?;
204 Ok(())
205 }
206
207 fn load_family(
208 &mut self,
209 name: &str,
210 features: &FontFeatures,
211 fallbacks: Option<&FontFallbacks>,
212 ) -> Result<SmallVec<[FontId; 4]>> {
213 let name = if name == ".SystemUIFont" {
214 ".AppleSystemUIFont"
215 } else {
216 name
217 };
218
219 let mut font_ids = SmallVec::new();
220 let family = self
221 .memory_source
222 .select_family_by_name(name)
223 .or_else(|_| self.system_source.select_family_by_name(name))?;
224 for font in family.fonts() {
225 let mut font = font.load()?;
226
227 apply_features_and_fallbacks(&mut font, features, fallbacks)?;
228 // This block contains a precautionary fix to guard against loading fonts
229 // that might cause panics due to `.unwrap()`s up the chain.
230 {
231 // We use the 'm' character for text measurements in various spots
232 // (e.g., the editor). However, at time of writing some of those usages
233 // will panic if the font has no 'm' glyph.
234 //
235 // Therefore, we check up front that the font has the necessary glyph.
236 let has_m_glyph = font.glyph_for_char('m').is_some();
237
238 // HACK: The 'Segoe Fluent Icons' font does not have an 'm' glyph,
239 // but we need to be able to load it for rendering Windows icons in
240 // the Storybook (on macOS).
241 let is_segoe_fluent_icons = font.full_name() == "Segoe Fluent Icons";
242
243 if !has_m_glyph && !is_segoe_fluent_icons {
244 // I spent far too long trying to track down why a font missing the 'm'
245 // character wasn't loading. This log statement will hopefully save
246 // someone else from suffering the same fate.
247 log::warn!(
248 "font '{}' has no 'm' character and was not loaded",
249 font.full_name()
250 );
251 continue;
252 }
253 }
254
255 // We've seen a number of panics in production caused by calling font.properties()
256 // which unwraps a downcast to CFNumber. This is an attempt to avoid the panic,
257 // and to try and identify the incalcitrant font.
258 let traits = font.native_font().all_traits();
259 if unsafe {
260 !(traits
261 .get(kCTFontSymbolicTrait)
262 .downcast::<CFNumber>()
263 .is_some()
264 && traits
265 .get(kCTFontWidthTrait)
266 .downcast::<CFNumber>()
267 .is_some()
268 && traits
269 .get(kCTFontWeightTrait)
270 .downcast::<CFNumber>()
271 .is_some()
272 && traits
273 .get(kCTFontSlantTrait)
274 .downcast::<CFNumber>()
275 .is_some())
276 } {
277 log::error!(
278 "Failed to read traits for font {:?}",
279 font.postscript_name().unwrap()
280 );
281 continue;
282 }
283
284 let font_id = FontId(self.fonts.len());
285 font_ids.push(font_id);
286 let postscript_name = font.postscript_name().unwrap();
287 self.font_ids_by_postscript_name
288 .insert(postscript_name.clone(), font_id);
289 self.postscript_names_by_font_id
290 .insert(font_id, postscript_name);
291 self.fonts.push(font);
292 }
293 Ok(font_ids)
294 }
295
296 fn advance(&self, font_id: FontId, glyph_id: GlyphId) -> Result<Size<f32>> {
297 Ok(self.fonts[font_id.0].advance(glyph_id.0)?.into())
298 }
299
300 fn glyph_for_char(&self, font_id: FontId, ch: char) -> Option<GlyphId> {
301 self.fonts[font_id.0].glyph_for_char(ch).map(GlyphId)
302 }
303
304 fn id_for_native_font(&mut self, requested_font: CTFont) -> FontId {
305 let postscript_name = requested_font.postscript_name();
306 if let Some(font_id) = self.font_ids_by_postscript_name.get(&postscript_name) {
307 *font_id
308 } else {
309 let font_id = FontId(self.fonts.len());
310 self.font_ids_by_postscript_name
311 .insert(postscript_name.clone(), font_id);
312 self.postscript_names_by_font_id
313 .insert(font_id, postscript_name);
314 self.fonts
315 .push(font_kit::font::Font::from_core_graphics_font(
316 requested_font.copy_to_CGFont(),
317 ));
318 font_id
319 }
320 }
321
322 fn is_emoji(&self, font_id: FontId) -> bool {
323 self.postscript_names_by_font_id
324 .get(&font_id)
325 .map_or(false, |postscript_name| {
326 postscript_name == "AppleColorEmoji" || postscript_name == ".AppleColorEmojiUI"
327 })
328 }
329
330 fn raster_bounds(&self, params: &RenderGlyphParams) -> Result<Bounds<DevicePixels>> {
331 let font = &self.fonts[params.font_id.0];
332 let scale = Transform2F::from_scale(params.scale_factor);
333 Ok(font
334 .raster_bounds(
335 params.glyph_id.0,
336 params.font_size.into(),
337 scale,
338 HintingOptions::None,
339 font_kit::canvas::RasterizationOptions::GrayscaleAa,
340 )?
341 .into())
342 }
343
344 fn rasterize_glyph(
345 &self,
346 params: &RenderGlyphParams,
347 glyph_bounds: Bounds<DevicePixels>,
348 ) -> Result<(Size<DevicePixels>, Vec<u8>)> {
349 if glyph_bounds.size.width.0 == 0 || glyph_bounds.size.height.0 == 0 {
350 Err(anyhow!("glyph bounds are empty"))
351 } else {
352 // Add an extra pixel when the subpixel variant isn't zero to make room for anti-aliasing.
353 let mut bitmap_size = glyph_bounds.size;
354 if params.subpixel_variant.x > 0 {
355 bitmap_size.width += DevicePixels(1);
356 }
357 if params.subpixel_variant.y > 0 {
358 bitmap_size.height += DevicePixels(1);
359 }
360 let bitmap_size = bitmap_size;
361
362 let mut bytes;
363 let cx;
364 if params.is_emoji {
365 bytes = vec![0; bitmap_size.width.0 as usize * 4 * bitmap_size.height.0 as usize];
366 cx = CGContext::create_bitmap_context(
367 Some(bytes.as_mut_ptr() as *mut _),
368 bitmap_size.width.0 as usize,
369 bitmap_size.height.0 as usize,
370 8,
371 bitmap_size.width.0 as usize * 4,
372 &CGColorSpace::create_device_rgb(),
373 kCGImageAlphaPremultipliedLast,
374 );
375 } else {
376 bytes = vec![0; bitmap_size.width.0 as usize * bitmap_size.height.0 as usize];
377 cx = CGContext::create_bitmap_context(
378 Some(bytes.as_mut_ptr() as *mut _),
379 bitmap_size.width.0 as usize,
380 bitmap_size.height.0 as usize,
381 8,
382 bitmap_size.width.0 as usize,
383 &CGColorSpace::create_device_gray(),
384 kCGImageAlphaOnly,
385 );
386 }
387
388 // Move the origin to bottom left and account for scaling, this
389 // makes drawing text consistent with the font-kit's raster_bounds.
390 cx.translate(
391 -glyph_bounds.origin.x.0 as CGFloat,
392 (glyph_bounds.origin.y.0 + glyph_bounds.size.height.0) as CGFloat,
393 );
394 cx.scale(
395 params.scale_factor as CGFloat,
396 params.scale_factor as CGFloat,
397 );
398
399 let subpixel_shift = params
400 .subpixel_variant
401 .map(|v| v as f32 / SUBPIXEL_VARIANTS as f32);
402 cx.set_allows_font_subpixel_positioning(true);
403 cx.set_should_subpixel_position_fonts(true);
404 cx.set_allows_font_subpixel_quantization(false);
405 cx.set_should_subpixel_quantize_fonts(false);
406 self.fonts[params.font_id.0]
407 .native_font()
408 .clone_with_font_size(f32::from(params.font_size) as CGFloat)
409 .draw_glyphs(
410 &[params.glyph_id.0 as CGGlyph],
411 &[CGPoint::new(
412 (subpixel_shift.x / params.scale_factor) as CGFloat,
413 (subpixel_shift.y / params.scale_factor) as CGFloat,
414 )],
415 cx,
416 );
417
418 if params.is_emoji {
419 // Convert from RGBA with premultiplied alpha to BGRA with straight alpha.
420 for pixel in bytes.chunks_exact_mut(4) {
421 pixel.swap(0, 2);
422 let a = pixel[3] as f32 / 255.;
423 pixel[0] = (pixel[0] as f32 / a) as u8;
424 pixel[1] = (pixel[1] as f32 / a) as u8;
425 pixel[2] = (pixel[2] as f32 / a) as u8;
426 }
427 }
428
429 Ok((bitmap_size, bytes))
430 }
431 }
432
433 fn layout_line(&mut self, text: &str, font_size: Pixels, font_runs: &[FontRun]) -> LineLayout {
434 // Construct the attributed string, converting UTF8 ranges to UTF16 ranges.
435 let mut string = CFMutableAttributedString::new();
436 {
437 string.replace_str(&CFString::new(text), CFRange::init(0, 0));
438 let utf16_line_len = string.char_len() as usize;
439
440 let mut ix_converter = StringIndexConverter::new(text);
441 for run in font_runs {
442 let utf8_end = ix_converter.utf8_ix + run.len;
443 let utf16_start = ix_converter.utf16_ix;
444
445 if utf16_start >= utf16_line_len {
446 break;
447 }
448
449 ix_converter.advance_to_utf8_ix(utf8_end);
450 let utf16_end = cmp::min(ix_converter.utf16_ix, utf16_line_len);
451
452 let cf_range =
453 CFRange::init(utf16_start as isize, (utf16_end - utf16_start) as isize);
454
455 let font: &FontKitFont = &self.fonts[run.font_id.0];
456
457 unsafe {
458 string.set_attribute(
459 cf_range,
460 kCTFontAttributeName,
461 &font.native_font().clone_with_font_size(font_size.into()),
462 );
463 }
464
465 if utf16_end == utf16_line_len {
466 break;
467 }
468 }
469 }
470
471 // Retrieve the glyphs from the shaped line, converting UTF16 offsets to UTF8 offsets.
472 let line = CTLine::new_with_attributed_string(string.as_concrete_TypeRef());
473 let glyph_runs = line.glyph_runs();
474 let mut runs = Vec::with_capacity(glyph_runs.len() as usize);
475 let mut ix_converter = StringIndexConverter::new(text);
476 for run in glyph_runs.into_iter() {
477 let attributes = run.attributes().unwrap();
478 let font = unsafe {
479 attributes
480 .get(kCTFontAttributeName)
481 .downcast::<CTFont>()
482 .unwrap()
483 };
484 let font_id = self.id_for_native_font(font);
485
486 let mut glyphs = SmallVec::new();
487 for ((glyph_id, position), glyph_utf16_ix) in run
488 .glyphs()
489 .iter()
490 .zip(run.positions().iter())
491 .zip(run.string_indices().iter())
492 {
493 let glyph_utf16_ix = usize::try_from(*glyph_utf16_ix).unwrap();
494 if ix_converter.utf16_ix > glyph_utf16_ix {
495 // We cannot reuse current index converter, as it can only seek forward. Restart the search.
496 ix_converter = StringIndexConverter::new(text);
497 }
498 ix_converter.advance_to_utf16_ix(glyph_utf16_ix);
499 glyphs.push(ShapedGlyph {
500 id: GlyphId(*glyph_id as u32),
501 position: point(position.x as f32, position.y as f32).map(px),
502 index: ix_converter.utf8_ix,
503 is_emoji: self.is_emoji(font_id),
504 });
505 }
506
507 runs.push(ShapedRun { font_id, glyphs });
508 }
509 let typographic_bounds = line.get_typographic_bounds();
510 LineLayout {
511 runs,
512 font_size,
513 width: typographic_bounds.width.into(),
514 ascent: typographic_bounds.ascent.into(),
515 descent: typographic_bounds.descent.into(),
516 len: text.len(),
517 }
518 }
519}
520
521#[derive(Clone)]
522struct StringIndexConverter<'a> {
523 text: &'a str,
524 utf8_ix: usize,
525 utf16_ix: usize,
526}
527
528impl<'a> StringIndexConverter<'a> {
529 fn new(text: &'a str) -> Self {
530 Self {
531 text,
532 utf8_ix: 0,
533 utf16_ix: 0,
534 }
535 }
536
537 fn advance_to_utf8_ix(&mut self, utf8_target: usize) {
538 for (ix, c) in self.text[self.utf8_ix..].char_indices() {
539 if self.utf8_ix + ix >= utf8_target {
540 self.utf8_ix += ix;
541 return;
542 }
543 self.utf16_ix += c.len_utf16();
544 }
545 self.utf8_ix = self.text.len();
546 }
547
548 fn advance_to_utf16_ix(&mut self, utf16_target: usize) {
549 for (ix, c) in self.text[self.utf8_ix..].char_indices() {
550 if self.utf16_ix >= utf16_target {
551 self.utf8_ix += ix;
552 return;
553 }
554 self.utf16_ix += c.len_utf16();
555 }
556 self.utf8_ix = self.text.len();
557 }
558}
559
560impl From<Metrics> for FontMetrics {
561 fn from(metrics: Metrics) -> Self {
562 FontMetrics {
563 units_per_em: metrics.units_per_em,
564 ascent: metrics.ascent,
565 descent: metrics.descent,
566 line_gap: metrics.line_gap,
567 underline_position: metrics.underline_position,
568 underline_thickness: metrics.underline_thickness,
569 cap_height: metrics.cap_height,
570 x_height: metrics.x_height,
571 bounding_box: metrics.bounding_box.into(),
572 }
573 }
574}
575
576impl From<RectF> for Bounds<f32> {
577 fn from(rect: RectF) -> 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<RectI> for Bounds<DevicePixels> {
586 fn from(rect: RectI) -> Self {
587 Bounds {
588 origin: point(DevicePixels(rect.origin_x()), DevicePixels(rect.origin_y())),
589 size: size(DevicePixels(rect.width()), DevicePixels(rect.height())),
590 }
591 }
592}
593
594impl From<Vector2I> for Size<DevicePixels> {
595 fn from(value: Vector2I) -> Self {
596 size(value.x().into(), value.y().into())
597 }
598}
599
600impl From<RectI> for Bounds<i32> {
601 fn from(rect: RectI) -> Self {
602 Bounds {
603 origin: point(rect.origin_x(), rect.origin_y()),
604 size: size(rect.width(), rect.height()),
605 }
606 }
607}
608
609impl From<Point<u32>> for Vector2I {
610 fn from(size: Point<u32>) -> Self {
611 Vector2I::new(size.x as i32, size.y as i32)
612 }
613}
614
615impl From<Vector2F> for Size<f32> {
616 fn from(vec: Vector2F) -> Self {
617 size(vec.x(), vec.y())
618 }
619}
620
621impl From<FontWeight> for FontkitWeight {
622 fn from(value: FontWeight) -> Self {
623 FontkitWeight(value.0)
624 }
625}
626
627impl From<FontStyle> for FontkitStyle {
628 fn from(style: FontStyle) -> Self {
629 match style {
630 FontStyle::Normal => FontkitStyle::Normal,
631 FontStyle::Italic => FontkitStyle::Italic,
632 FontStyle::Oblique => FontkitStyle::Oblique,
633 }
634 }
635}
636
637// Some fonts may have no attributes despite `core_text` requiring them (and panicking).
638// This is the same version as `core_text` has without `expect` calls.
639mod lenient_font_attributes {
640 use core_foundation::{
641 base::{CFRetain, CFType, TCFType},
642 string::{CFString, CFStringRef},
643 };
644 use core_text::font_descriptor::{
645 kCTFontFamilyNameAttribute, CTFontDescriptor, CTFontDescriptorCopyAttribute,
646 };
647
648 pub fn family_name(descriptor: &CTFontDescriptor) -> Option<String> {
649 unsafe { get_string_attribute(descriptor, kCTFontFamilyNameAttribute) }
650 }
651
652 fn get_string_attribute(
653 descriptor: &CTFontDescriptor,
654 attribute: CFStringRef,
655 ) -> Option<String> {
656 unsafe {
657 let value = CTFontDescriptorCopyAttribute(descriptor.as_concrete_TypeRef(), attribute);
658 if value.is_null() {
659 return None;
660 }
661
662 let value = CFType::wrap_under_create_rule(value);
663 assert!(value.instance_of::<CFString>());
664 let s = wrap_under_get_rule(value.as_CFTypeRef() as CFStringRef);
665 Some(s.to_string())
666 }
667 }
668
669 unsafe fn wrap_under_get_rule(reference: CFStringRef) -> CFString {
670 assert!(!reference.is_null(), "Attempted to create a NULL object.");
671 let reference = CFRetain(reference as *const ::std::os::raw::c_void) as CFStringRef;
672 TCFType::wrap_under_create_rule(reference)
673 }
674}
675
676#[cfg(test)]
677mod tests {
678 use crate::{font, px, FontRun, GlyphId, MacTextSystem, PlatformTextSystem};
679
680 #[test]
681 fn test_layout_line_bom_char() {
682 let fonts = MacTextSystem::new();
683 let font_id = fonts.font_id(&font("Helvetica")).unwrap();
684 let line = "\u{feff}";
685 let mut style = FontRun {
686 font_id,
687 len: line.len(),
688 };
689
690 let layout = fonts.layout_line(line, px(16.), &[style]);
691 assert_eq!(layout.len, line.len());
692 assert!(layout.runs.is_empty());
693
694 let line = "a\u{feff}b";
695 style.len = line.len();
696 let layout = fonts.layout_line(line, px(16.), &[style]);
697 assert_eq!(layout.len, line.len());
698 assert_eq!(layout.runs.len(), 1);
699 assert_eq!(layout.runs[0].glyphs.len(), 2);
700 assert_eq!(layout.runs[0].glyphs[0].id, GlyphId(68u32)); // a
701 // There's no glyph for \u{feff}
702 assert_eq!(layout.runs[0].glyphs[1].id, GlyphId(69u32)); // b
703 }
704}