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