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 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 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![];
85 };
86 let mut names = BTreeSet::new();
87 for descriptor in descriptors.into_iter() {
88 names.insert(descriptor.display_name());
89 }
90 names.into_iter().collect()
91 }
92
93 fn font_id(&self, font: &Font) -> Result<FontId> {
94 let lock = self.0.upgradable_read();
95 if let Some(font_id) = lock.font_selections.get(font) {
96 Ok(*font_id)
97 } else {
98 let mut lock = RwLockUpgradableReadGuard::upgrade(lock);
99 let candidates = if let Some(font_ids) = lock.font_ids_by_family_name.get(&font.family)
100 {
101 font_ids.as_slice()
102 } else {
103 let font_ids = lock.load_family(&font.family, font.features)?;
104 lock.font_ids_by_family_name
105 .insert(font.family.clone(), font_ids);
106 lock.font_ids_by_family_name[&font.family].as_ref()
107 };
108
109 let candidate_properties = candidates
110 .iter()
111 .map(|font_id| lock.fonts[font_id.0].properties())
112 .collect::<SmallVec<[_; 4]>>();
113
114 let ix = font_kit::matching::find_best_match(
115 &candidate_properties,
116 &font_kit::properties::Properties {
117 style: font.style.into(),
118 weight: font.weight.into(),
119 stretch: Default::default(),
120 },
121 )?;
122
123 let font_id = candidates[ix];
124 lock.font_selections.insert(font.clone(), font_id);
125 Ok(font_id)
126 }
127 }
128
129 fn font_metrics(&self, font_id: FontId) -> FontMetrics {
130 self.0.read().fonts[font_id.0].metrics().into()
131 }
132
133 fn typographic_bounds(&self, font_id: FontId, glyph_id: GlyphId) -> Result<Bounds<f32>> {
134 Ok(self.0.read().fonts[font_id.0]
135 .typographic_bounds(glyph_id.into())?
136 .into())
137 }
138
139 fn advance(&self, font_id: FontId, glyph_id: GlyphId) -> Result<Size<f32>> {
140 self.0.read().advance(font_id, glyph_id)
141 }
142
143 fn glyph_for_char(&self, font_id: FontId, ch: char) -> Option<GlyphId> {
144 self.0.read().glyph_for_char(font_id, ch)
145 }
146
147 fn glyph_raster_bounds(&self, params: &RenderGlyphParams) -> Result<Bounds<DevicePixels>> {
148 self.0.read().raster_bounds(params)
149 }
150
151 fn rasterize_glyph(
152 &self,
153 glyph_id: &RenderGlyphParams,
154 raster_bounds: Bounds<DevicePixels>,
155 ) -> Result<(Size<DevicePixels>, Vec<u8>)> {
156 self.0.read().rasterize_glyph(glyph_id, raster_bounds)
157 }
158
159 fn layout_line(&self, text: &str, font_size: Pixels, font_runs: &[FontRun]) -> LineLayout {
160 self.0.write().layout_line(text, font_size, font_runs)
161 }
162
163 fn wrap_line(
164 &self,
165 text: &str,
166 font_id: FontId,
167 font_size: Pixels,
168 width: Pixels,
169 ) -> Vec<usize> {
170 self.0.read().wrap_line(text, font_id, font_size, width)
171 }
172}
173
174impl MacTextSystemState {
175 fn add_fonts(&mut self, fonts: &[Arc<Vec<u8>>]) -> Result<()> {
176 self.memory_source.add_fonts(
177 fonts
178 .iter()
179 .map(|bytes| Handle::from_memory(bytes.clone(), 0)),
180 )?;
181 Ok(())
182 }
183
184 fn load_family(
185 &mut self,
186 name: &SharedString,
187 features: FontFeatures,
188 ) -> Result<SmallVec<[FontId; 4]>> {
189 let mut font_ids = SmallVec::new();
190 let family = self
191 .memory_source
192 .select_family_by_name(name.as_ref())
193 .or_else(|_| self.system_source.select_family_by_name(name.as_ref()))?;
194 for font in family.fonts() {
195 let mut font = font.load()?;
196 open_type::apply_features(&mut font, features);
197 let Some(_) = font.glyph_for_char('m') else {
198 continue;
199 };
200 let font_id = FontId(self.fonts.len());
201 font_ids.push(font_id);
202 let postscript_name = font.postscript_name().unwrap();
203 self.font_ids_by_postscript_name
204 .insert(postscript_name.clone(), font_id);
205 self.postscript_names_by_font_id
206 .insert(font_id, postscript_name);
207 self.fonts.push(font);
208 }
209 Ok(font_ids)
210 }
211
212 fn advance(&self, font_id: FontId, glyph_id: GlyphId) -> Result<Size<f32>> {
213 Ok(self.fonts[font_id.0].advance(glyph_id.into())?.into())
214 }
215
216 fn glyph_for_char(&self, font_id: FontId, ch: char) -> Option<GlyphId> {
217 self.fonts[font_id.0].glyph_for_char(ch).map(Into::into)
218 }
219
220 fn id_for_native_font(&mut self, requested_font: CTFont) -> FontId {
221 let postscript_name = requested_font.postscript_name();
222 if let Some(font_id) = self.font_ids_by_postscript_name.get(&postscript_name) {
223 *font_id
224 } else {
225 let font_id = FontId(self.fonts.len());
226 self.font_ids_by_postscript_name
227 .insert(postscript_name.clone(), font_id);
228 self.postscript_names_by_font_id
229 .insert(font_id, postscript_name);
230 self.fonts
231 .push(font_kit::font::Font::from_core_graphics_font(
232 requested_font.copy_to_CGFont(),
233 ));
234 font_id
235 }
236 }
237
238 fn is_emoji(&self, font_id: FontId) -> bool {
239 self.postscript_names_by_font_id
240 .get(&font_id)
241 .map_or(false, |postscript_name| {
242 postscript_name == "AppleColorEmoji"
243 })
244 }
245
246 fn raster_bounds(&self, params: &RenderGlyphParams) -> Result<Bounds<DevicePixels>> {
247 let font = &self.fonts[params.font_id.0];
248 let scale = Transform2F::from_scale(params.scale_factor);
249 Ok(font
250 .raster_bounds(
251 params.glyph_id.into(),
252 params.font_size.into(),
253 scale,
254 HintingOptions::None,
255 font_kit::canvas::RasterizationOptions::GrayscaleAa,
256 )?
257 .into())
258 }
259
260 fn rasterize_glyph(
261 &self,
262 params: &RenderGlyphParams,
263 glyph_bounds: Bounds<DevicePixels>,
264 ) -> Result<(Size<DevicePixels>, Vec<u8>)> {
265 if glyph_bounds.size.width.0 == 0 || glyph_bounds.size.height.0 == 0 {
266 Err(anyhow!("glyph bounds are empty"))
267 } else {
268 // Add an extra pixel when the subpixel variant isn't zero to make room for anti-aliasing.
269 let mut bitmap_size = glyph_bounds.size;
270 if params.subpixel_variant.x > 0 {
271 bitmap_size.width += DevicePixels(1);
272 }
273 if params.subpixel_variant.y > 0 {
274 bitmap_size.height += DevicePixels(1);
275 }
276 let bitmap_size = bitmap_size;
277
278 let mut bytes;
279 let cx;
280 if params.is_emoji {
281 bytes = vec![0; bitmap_size.width.0 as usize * 4 * bitmap_size.height.0 as usize];
282 cx = CGContext::create_bitmap_context(
283 Some(bytes.as_mut_ptr() as *mut _),
284 bitmap_size.width.0 as usize,
285 bitmap_size.height.0 as usize,
286 8,
287 bitmap_size.width.0 as usize * 4,
288 &CGColorSpace::create_device_rgb(),
289 kCGImageAlphaPremultipliedLast,
290 );
291 } else {
292 bytes = vec![0; bitmap_size.width.0 as usize * 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,
299 &CGColorSpace::create_device_gray(),
300 kCGImageAlphaOnly,
301 );
302 }
303
304 // Move the origin to bottom left and account for scaling, this
305 // makes drawing text consistent with the font-kit's raster_bounds.
306 cx.translate(
307 -glyph_bounds.origin.x.0 as CGFloat,
308 (glyph_bounds.origin.y.0 + glyph_bounds.size.height.0) as CGFloat,
309 );
310 cx.scale(
311 params.scale_factor as CGFloat,
312 params.scale_factor as CGFloat,
313 );
314
315 let subpixel_shift = params
316 .subpixel_variant
317 .map(|v| v as f32 / SUBPIXEL_VARIANTS as f32);
318 cx.set_allows_font_subpixel_positioning(true);
319 cx.set_should_subpixel_position_fonts(true);
320 cx.set_allows_font_subpixel_quantization(false);
321 cx.set_should_subpixel_quantize_fonts(false);
322 self.fonts[params.font_id.0]
323 .native_font()
324 .clone_with_font_size(f32::from(params.font_size) as CGFloat)
325 .draw_glyphs(
326 &[u32::from(params.glyph_id) as CGGlyph],
327 &[CGPoint::new(
328 (subpixel_shift.x / params.scale_factor) as CGFloat,
329 (subpixel_shift.y / params.scale_factor) as CGFloat,
330 )],
331 cx,
332 );
333
334 if params.is_emoji {
335 // Convert from RGBA with premultiplied alpha to BGRA with straight alpha.
336 for pixel in bytes.chunks_exact_mut(4) {
337 pixel.swap(0, 2);
338 let a = pixel[3] as f32 / 255.;
339 pixel[0] = (pixel[0] as f32 / a) as u8;
340 pixel[1] = (pixel[1] as f32 / a) as u8;
341 pixel[2] = (pixel[2] as f32 / a) as u8;
342 }
343 }
344
345 Ok((bitmap_size, bytes))
346 }
347 }
348
349 fn layout_line(&mut self, text: &str, font_size: Pixels, font_runs: &[FontRun]) -> LineLayout {
350 // Construct the attributed string, converting UTF8 ranges to UTF16 ranges.
351 let mut string = CFMutableAttributedString::new();
352 {
353 string.replace_str(&CFString::new(text), CFRange::init(0, 0));
354 let utf16_line_len = string.char_len() as usize;
355
356 let mut ix_converter = StringIndexConverter::new(text);
357 for run in font_runs {
358 let utf8_end = ix_converter.utf8_ix + run.len;
359 let utf16_start = ix_converter.utf16_ix;
360
361 if utf16_start >= utf16_line_len {
362 break;
363 }
364
365 ix_converter.advance_to_utf8_ix(utf8_end);
366 let utf16_end = cmp::min(ix_converter.utf16_ix, utf16_line_len);
367
368 let cf_range =
369 CFRange::init(utf16_start as isize, (utf16_end - utf16_start) as isize);
370
371 let font: &FontKitFont = &self.fonts[run.font_id.0];
372 unsafe {
373 string.set_attribute(
374 cf_range,
375 kCTFontAttributeName,
376 &font.native_font().clone_with_font_size(font_size.into()),
377 );
378 }
379
380 if utf16_end == utf16_line_len {
381 break;
382 }
383 }
384 }
385
386 // Retrieve the glyphs from the shaped line, converting UTF16 offsets to UTF8 offsets.
387 let line = CTLine::new_with_attributed_string(string.as_concrete_TypeRef());
388
389 let mut runs = Vec::new();
390 for run in line.glyph_runs().into_iter() {
391 let attributes = run.attributes().unwrap();
392 let font = unsafe {
393 attributes
394 .get(kCTFontAttributeName)
395 .downcast::<CTFont>()
396 .unwrap()
397 };
398 let font_id = self.id_for_native_font(font);
399
400 let mut ix_converter = StringIndexConverter::new(text);
401 let mut glyphs = SmallVec::new();
402 for ((glyph_id, position), glyph_utf16_ix) in run
403 .glyphs()
404 .iter()
405 .zip(run.positions().iter())
406 .zip(run.string_indices().iter())
407 {
408 let glyph_utf16_ix = usize::try_from(*glyph_utf16_ix).unwrap();
409 ix_converter.advance_to_utf16_ix(glyph_utf16_ix);
410 glyphs.push(ShapedGlyph {
411 id: (*glyph_id).into(),
412 position: point(position.x as f32, position.y as f32).map(px),
413 index: ix_converter.utf8_ix,
414 is_emoji: self.is_emoji(font_id),
415 });
416 }
417
418 runs.push(ShapedRun { font_id, glyphs })
419 }
420
421 let typographic_bounds = line.get_typographic_bounds();
422 LineLayout {
423 runs,
424 font_size,
425 width: typographic_bounds.width.into(),
426 ascent: typographic_bounds.ascent.into(),
427 descent: typographic_bounds.descent.into(),
428 len: text.len(),
429 }
430 }
431
432 fn wrap_line(
433 &self,
434 text: &str,
435 font_id: FontId,
436 font_size: Pixels,
437 width: Pixels,
438 ) -> Vec<usize> {
439 let mut string = CFMutableAttributedString::new();
440 string.replace_str(&CFString::new(text), CFRange::init(0, 0));
441 let cf_range = CFRange::init(0, text.encode_utf16().count() as isize);
442 let font = &self.fonts[font_id.0];
443 unsafe {
444 string.set_attribute(
445 cf_range,
446 kCTFontAttributeName,
447 &font.native_font().clone_with_font_size(font_size.into()),
448 );
449
450 let typesetter = CTTypesetterCreateWithAttributedString(string.as_concrete_TypeRef());
451 let mut ix_converter = StringIndexConverter::new(text);
452 let mut break_indices = Vec::new();
453 while ix_converter.utf8_ix < text.len() {
454 let utf16_len = CTTypesetterSuggestLineBreak(
455 typesetter,
456 ix_converter.utf16_ix as isize,
457 width.into(),
458 ) as usize;
459 ix_converter.advance_to_utf16_ix(ix_converter.utf16_ix + utf16_len);
460 if ix_converter.utf8_ix >= text.len() {
461 break;
462 }
463 break_indices.push(ix_converter.utf8_ix);
464 }
465 break_indices
466 }
467 }
468}
469
470#[derive(Clone)]
471struct StringIndexConverter<'a> {
472 text: &'a str,
473 utf8_ix: usize,
474 utf16_ix: usize,
475}
476
477impl<'a> StringIndexConverter<'a> {
478 fn new(text: &'a str) -> Self {
479 Self {
480 text,
481 utf8_ix: 0,
482 utf16_ix: 0,
483 }
484 }
485
486 fn advance_to_utf8_ix(&mut self, utf8_target: usize) {
487 for (ix, c) in self.text[self.utf8_ix..].char_indices() {
488 if self.utf8_ix + ix >= utf8_target {
489 self.utf8_ix += ix;
490 return;
491 }
492 self.utf16_ix += c.len_utf16();
493 }
494 self.utf8_ix = self.text.len();
495 }
496
497 fn advance_to_utf16_ix(&mut self, utf16_target: usize) {
498 for (ix, c) in self.text[self.utf8_ix..].char_indices() {
499 if self.utf16_ix >= utf16_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
509#[repr(C)]
510pub(crate) struct __CFTypesetter(c_void);
511
512type CTTypesetterRef = *const __CFTypesetter;
513
514#[link(name = "CoreText", kind = "framework")]
515extern "C" {
516 fn CTTypesetterCreateWithAttributedString(string: CFAttributedStringRef) -> CTTypesetterRef;
517
518 fn CTTypesetterSuggestLineBreak(
519 typesetter: CTTypesetterRef,
520 start_index: CFIndex,
521 width: f64,
522 ) -> CFIndex;
523}
524
525impl From<Metrics> for FontMetrics {
526 fn from(metrics: Metrics) -> Self {
527 FontMetrics {
528 units_per_em: metrics.units_per_em,
529 ascent: metrics.ascent,
530 descent: metrics.descent,
531 line_gap: metrics.line_gap,
532 underline_position: metrics.underline_position,
533 underline_thickness: metrics.underline_thickness,
534 cap_height: metrics.cap_height,
535 x_height: metrics.x_height,
536 bounding_box: metrics.bounding_box.into(),
537 }
538 }
539}
540
541impl From<RectF> for Bounds<f32> {
542 fn from(rect: RectF) -> Self {
543 Bounds {
544 origin: point(rect.origin_x(), rect.origin_y()),
545 size: size(rect.width(), rect.height()),
546 }
547 }
548}
549
550impl From<RectI> for Bounds<DevicePixels> {
551 fn from(rect: RectI) -> Self {
552 Bounds {
553 origin: point(DevicePixels(rect.origin_x()), DevicePixels(rect.origin_y())),
554 size: size(DevicePixels(rect.width()), DevicePixels(rect.height())),
555 }
556 }
557}
558
559impl From<Vector2I> for Size<DevicePixels> {
560 fn from(value: Vector2I) -> Self {
561 size(value.x().into(), value.y().into())
562 }
563}
564
565impl From<RectI> for Bounds<i32> {
566 fn from(rect: RectI) -> Self {
567 Bounds {
568 origin: point(rect.origin_x(), rect.origin_y()),
569 size: size(rect.width(), rect.height()),
570 }
571 }
572}
573
574impl From<Point<u32>> for Vector2I {
575 fn from(size: Point<u32>) -> Self {
576 Vector2I::new(size.x as i32, size.y as i32)
577 }
578}
579
580impl From<Vector2F> for Size<f32> {
581 fn from(vec: Vector2F) -> Self {
582 size(vec.x(), vec.y())
583 }
584}
585
586impl From<FontWeight> for FontkitWeight {
587 fn from(value: FontWeight) -> Self {
588 FontkitWeight(value.0)
589 }
590}
591
592impl From<FontStyle> for FontkitStyle {
593 fn from(style: FontStyle) -> Self {
594 match style {
595 FontStyle::Normal => FontkitStyle::Normal,
596 FontStyle::Italic => FontkitStyle::Italic,
597 FontStyle::Oblique => FontkitStyle::Oblique,
598 }
599 }
600}
601
602#[cfg(test)]
603mod tests {
604 use crate::{font, px, FontRun, MacTextSystem, PlatformTextSystem};
605
606 #[test]
607 fn test_wrap_line() {
608 let fonts = MacTextSystem::new();
609 let font_id = fonts.font_id(&font("Helvetica")).unwrap();
610
611 let line = "one two three four five\n";
612 let wrap_boundaries = fonts.wrap_line(line, font_id, px(16.), px(64.0));
613 assert_eq!(wrap_boundaries, &["one two ".len(), "one two three ".len()]);
614
615 let line = "aaa ααα ✋✋✋ 🎉🎉🎉\n";
616 let wrap_boundaries = fonts.wrap_line(line, font_id, px(16.), px(64.0));
617 assert_eq!(
618 wrap_boundaries,
619 &["aaa ααα ".len(), "aaa ααα ✋✋✋ ".len(),]
620 );
621 }
622
623 #[test]
624 fn test_layout_line_bom_char() {
625 let fonts = MacTextSystem::new();
626 let font_id = fonts.font_id(&font("Helvetica")).unwrap();
627 let line = "\u{feff}";
628 let mut style = FontRun {
629 font_id,
630 len: line.len(),
631 };
632
633 let layout = fonts.layout_line(line, px(16.), &[style]);
634 assert_eq!(layout.len, line.len());
635 assert!(layout.runs.is_empty());
636
637 let line = "a\u{feff}b";
638 style.len = line.len();
639 let layout = fonts.layout_line(line, px(16.), &[style]);
640 assert_eq!(layout.len, line.len());
641 assert_eq!(layout.runs.len(), 1);
642 assert_eq!(layout.runs[0].glyphs.len(), 2);
643 assert_eq!(layout.runs[0].glyphs[0].id, 68u32.into()); // a
644 // There's no glyph for \u{feff}
645 assert_eq!(layout.runs[0].glyphs[1].id, 69u32.into()); // b
646 }
647}