1use crate::{
2 fonts::{FontId, GlyphId, Metrics, Properties},
3 geometry::{
4 rect::{RectF, RectI},
5 transform2d::Transform2F,
6 vector::{vec2f, Vector2F},
7 },
8 platform::{self, RasterizationOptions},
9 text_layout::{Glyph, LineLayout, Run, RunStyle},
10};
11use cocoa::appkit::{CGFloat, CGPoint};
12use collections::HashMap;
13use core_foundation::{
14 array::CFIndex,
15 attributed_string::{CFAttributedStringRef, CFMutableAttributedString},
16 base::{CFRange, TCFType},
17 string::CFString,
18};
19use core_graphics::{
20 base::{kCGImageAlphaPremultipliedLast, CGGlyph},
21 color_space::CGColorSpace,
22 context::CGContext,
23};
24use core_text::{font::CTFont, line::CTLine, string_attributes::kCTFontAttributeName};
25use font_kit::{
26 handle::Handle, hinting::HintingOptions, source::SystemSource, sources::mem::MemSource,
27};
28use parking_lot::RwLock;
29use std::{cell::RefCell, char, cmp, convert::TryFrom, ffi::c_void, sync::Arc};
30
31#[allow(non_upper_case_globals)]
32const kCGImageAlphaOnly: u32 = 7;
33
34pub struct FontSystem(RwLock<FontSystemState>);
35
36struct FontSystemState {
37 memory_source: MemSource,
38 system_source: SystemSource,
39 fonts: Vec<font_kit::font::Font>,
40 font_ids_by_postscript_name: HashMap<String, FontId>,
41 postscript_names_by_font_id: HashMap<FontId, String>,
42}
43
44impl FontSystem {
45 pub fn new() -> Self {
46 Self(RwLock::new(FontSystemState {
47 memory_source: MemSource::empty(),
48 system_source: SystemSource::new(),
49 fonts: Vec::new(),
50 font_ids_by_postscript_name: Default::default(),
51 postscript_names_by_font_id: Default::default(),
52 }))
53 }
54}
55
56impl platform::FontSystem for FontSystem {
57 fn add_fonts(&self, fonts: &[Arc<Vec<u8>>]) -> anyhow::Result<()> {
58 self.0.write().add_fonts(fonts)
59 }
60
61 fn load_family(&self, name: &str) -> anyhow::Result<Vec<FontId>> {
62 self.0.write().load_family(name)
63 }
64
65 fn select_font(&self, font_ids: &[FontId], properties: &Properties) -> anyhow::Result<FontId> {
66 self.0.read().select_font(font_ids, properties)
67 }
68
69 fn font_metrics(&self, font_id: FontId) -> Metrics {
70 self.0.read().font_metrics(font_id)
71 }
72
73 fn typographic_bounds(&self, font_id: FontId, glyph_id: GlyphId) -> anyhow::Result<RectF> {
74 self.0.read().typographic_bounds(font_id, glyph_id)
75 }
76
77 fn advance(&self, font_id: FontId, glyph_id: GlyphId) -> anyhow::Result<Vector2F> {
78 self.0.read().advance(font_id, glyph_id)
79 }
80
81 fn glyph_for_char(&self, font_id: FontId, ch: char) -> Option<GlyphId> {
82 self.0.read().glyph_for_char(font_id, ch)
83 }
84
85 fn rasterize_glyph(
86 &self,
87 font_id: FontId,
88 font_size: f32,
89 glyph_id: GlyphId,
90 subpixel_shift: Vector2F,
91 scale_factor: f32,
92 options: RasterizationOptions,
93 ) -> Option<(RectI, Vec<u8>)> {
94 self.0.read().rasterize_glyph(
95 font_id,
96 font_size,
97 glyph_id,
98 subpixel_shift,
99 scale_factor,
100 options,
101 )
102 }
103
104 fn layout_line(&self, text: &str, font_size: f32, runs: &[(usize, RunStyle)]) -> LineLayout {
105 self.0.write().layout_line(text, font_size, runs)
106 }
107
108 fn wrap_line(&self, text: &str, font_id: FontId, font_size: f32, width: f32) -> Vec<usize> {
109 self.0.read().wrap_line(text, font_id, font_size, width)
110 }
111}
112
113impl FontSystemState {
114 fn add_fonts(&mut self, fonts: &[Arc<Vec<u8>>]) -> anyhow::Result<()> {
115 self.memory_source.add_fonts(
116 fonts
117 .iter()
118 .map(|bytes| Handle::from_memory(bytes.clone(), 0)),
119 )?;
120 Ok(())
121 }
122
123 fn load_family(&mut self, name: &str) -> anyhow::Result<Vec<FontId>> {
124 let mut font_ids = Vec::new();
125
126 let family = self
127 .memory_source
128 .select_family_by_name(name)
129 .or_else(|_| self.system_source.select_family_by_name(name))?;
130 for font in family.fonts() {
131 let font = font.load()?;
132 let font_id = FontId(self.fonts.len());
133 font_ids.push(font_id);
134 let postscript_name = font.postscript_name().unwrap();
135 self.font_ids_by_postscript_name
136 .insert(postscript_name.clone(), font_id);
137 self.postscript_names_by_font_id
138 .insert(font_id, postscript_name);
139 self.fonts.push(font);
140 }
141 Ok(font_ids)
142 }
143
144 fn select_font(&self, font_ids: &[FontId], properties: &Properties) -> anyhow::Result<FontId> {
145 let candidates = font_ids
146 .iter()
147 .map(|font_id| self.fonts[font_id.0].properties())
148 .collect::<Vec<_>>();
149 let idx = font_kit::matching::find_best_match(&candidates, properties)?;
150 Ok(font_ids[idx])
151 }
152
153 fn font_metrics(&self, font_id: FontId) -> Metrics {
154 self.fonts[font_id.0].metrics()
155 }
156
157 fn typographic_bounds(&self, font_id: FontId, glyph_id: GlyphId) -> anyhow::Result<RectF> {
158 Ok(self.fonts[font_id.0].typographic_bounds(glyph_id)?)
159 }
160
161 fn advance(&self, font_id: FontId, glyph_id: GlyphId) -> anyhow::Result<Vector2F> {
162 Ok(self.fonts[font_id.0].advance(glyph_id)?)
163 }
164
165 fn glyph_for_char(&self, font_id: FontId, ch: char) -> Option<GlyphId> {
166 self.fonts[font_id.0].glyph_for_char(ch)
167 }
168
169 fn id_for_native_font(&mut self, requested_font: CTFont) -> FontId {
170 let postscript_name = requested_font.postscript_name();
171 if let Some(font_id) = self.font_ids_by_postscript_name.get(&postscript_name) {
172 *font_id
173 } else {
174 let font_id = FontId(self.fonts.len());
175 self.font_ids_by_postscript_name
176 .insert(postscript_name.clone(), font_id);
177 self.postscript_names_by_font_id
178 .insert(font_id, postscript_name);
179 self.fonts
180 .push(font_kit::font::Font::from_core_graphics_font(
181 requested_font.copy_to_CGFont(),
182 ));
183 font_id
184 }
185 }
186
187 fn is_emoji(&self, font_id: FontId) -> bool {
188 self.postscript_names_by_font_id
189 .get(&font_id)
190 .map_or(false, |postscript_name| {
191 postscript_name == "AppleColorEmoji"
192 })
193 }
194
195 fn rasterize_glyph(
196 &self,
197 font_id: FontId,
198 font_size: f32,
199 glyph_id: GlyphId,
200 subpixel_shift: Vector2F,
201 scale_factor: f32,
202 options: RasterizationOptions,
203 ) -> Option<(RectI, Vec<u8>)> {
204 let font = &self.fonts[font_id.0];
205 let scale = Transform2F::from_scale(scale_factor);
206 let glyph_bounds = font
207 .raster_bounds(
208 glyph_id,
209 font_size,
210 scale,
211 HintingOptions::None,
212 font_kit::canvas::RasterizationOptions::GrayscaleAa,
213 )
214 .ok()?;
215
216 if glyph_bounds.width() == 0 || glyph_bounds.height() == 0 {
217 None
218 } else {
219 // Make room for subpixel variants.
220 let subpixel_padding = subpixel_shift.ceil().to_i32();
221 let cx_bounds = RectI::new(
222 glyph_bounds.origin(),
223 glyph_bounds.size() + subpixel_padding,
224 );
225
226 let mut bytes;
227 let cx;
228 match options {
229 RasterizationOptions::Alpha => {
230 bytes = vec![0; cx_bounds.width() as usize * cx_bounds.height() as usize];
231 cx = CGContext::create_bitmap_context(
232 Some(bytes.as_mut_ptr() as *mut _),
233 cx_bounds.width() as usize,
234 cx_bounds.height() as usize,
235 8,
236 cx_bounds.width() as usize,
237 &CGColorSpace::create_device_gray(),
238 kCGImageAlphaOnly,
239 );
240 }
241 RasterizationOptions::Bgra => {
242 bytes = vec![0; cx_bounds.width() as usize * 4 * cx_bounds.height() as usize];
243 cx = CGContext::create_bitmap_context(
244 Some(bytes.as_mut_ptr() as *mut _),
245 cx_bounds.width() as usize,
246 cx_bounds.height() as usize,
247 8,
248 cx_bounds.width() as usize * 4,
249 &CGColorSpace::create_device_rgb(),
250 kCGImageAlphaPremultipliedLast,
251 );
252 }
253 }
254
255 // Move the origin to bottom left and account for scaling, this
256 // makes drawing text consistent with the font-kit's raster_bounds.
257 cx.translate(
258 -glyph_bounds.origin_x() as CGFloat,
259 (glyph_bounds.origin_y() + glyph_bounds.height()) as CGFloat,
260 );
261 cx.scale(scale_factor as CGFloat, scale_factor as CGFloat);
262
263 cx.set_allows_font_subpixel_positioning(true);
264 cx.set_should_subpixel_position_fonts(true);
265 cx.set_allows_font_subpixel_quantization(false);
266 cx.set_should_subpixel_quantize_fonts(false);
267 font.native_font()
268 .clone_with_font_size(font_size as CGFloat)
269 .draw_glyphs(
270 &[glyph_id as CGGlyph],
271 &[CGPoint::new(
272 (subpixel_shift.x() / scale_factor) as CGFloat,
273 (subpixel_shift.y() / scale_factor) as CGFloat,
274 )],
275 cx,
276 );
277
278 if let RasterizationOptions::Bgra = options {
279 // Convert from RGBA with premultiplied alpha to BGRA with straight alpha.
280 for pixel in bytes.chunks_exact_mut(4) {
281 pixel.swap(0, 2);
282 let a = pixel[3] as f32 / 255.;
283 pixel[0] = (pixel[0] as f32 / a) as u8;
284 pixel[1] = (pixel[1] as f32 / a) as u8;
285 pixel[2] = (pixel[2] as f32 / a) as u8;
286 }
287 }
288
289 Some((cx_bounds, bytes))
290 }
291 }
292
293 fn layout_line(
294 &mut self,
295 text: &str,
296 font_size: f32,
297 runs: &[(usize, RunStyle)],
298 ) -> LineLayout {
299 // Construct the attributed string, converting UTF8 ranges to UTF16 ranges.
300 let mut string = CFMutableAttributedString::new();
301 {
302 string.replace_str(&CFString::new(text), CFRange::init(0, 0));
303 let utf16_line_len = string.char_len() as usize;
304
305 let last_run: RefCell<Option<(usize, FontId)>> = Default::default();
306 let font_runs = runs
307 .iter()
308 .filter_map(|(len, style)| {
309 let mut last_run = last_run.borrow_mut();
310 if let Some((last_len, last_font_id)) = last_run.as_mut() {
311 if style.font_id == *last_font_id {
312 *last_len += *len;
313 None
314 } else {
315 let result = (*last_len, *last_font_id);
316 *last_len = *len;
317 *last_font_id = style.font_id;
318 Some(result)
319 }
320 } else {
321 *last_run = Some((*len, style.font_id));
322 None
323 }
324 })
325 .chain(std::iter::from_fn(|| last_run.borrow_mut().take()));
326
327 let mut ix_converter = StringIndexConverter::new(text);
328 for (run_len, font_id) in font_runs {
329 let utf8_end = ix_converter.utf8_ix + run_len;
330 let utf16_start = ix_converter.utf16_ix;
331
332 if utf16_start >= utf16_line_len {
333 break;
334 }
335
336 ix_converter.advance_to_utf8_ix(utf8_end);
337 let utf16_end = cmp::min(ix_converter.utf16_ix, utf16_line_len);
338
339 let cf_range =
340 CFRange::init(utf16_start as isize, (utf16_end - utf16_start) as isize);
341 let font = &self.fonts[font_id.0];
342 unsafe {
343 string.set_attribute(
344 cf_range,
345 kCTFontAttributeName,
346 &font.native_font().clone_with_font_size(font_size as f64),
347 );
348 }
349
350 if utf16_end == utf16_line_len {
351 break;
352 }
353 }
354 }
355
356 // Retrieve the glyphs from the shaped line, converting UTF16 offsets to UTF8 offsets.
357 let line = CTLine::new_with_attributed_string(string.as_concrete_TypeRef());
358
359 let mut runs = Vec::new();
360 for run in line.glyph_runs().into_iter() {
361 let attributes = run.attributes().unwrap();
362 let font = unsafe {
363 attributes
364 .get(kCTFontAttributeName)
365 .downcast::<CTFont>()
366 .unwrap()
367 };
368 let font_id = self.id_for_native_font(font);
369
370 let mut ix_converter = StringIndexConverter::new(text);
371 let mut glyphs = Vec::new();
372 for ((glyph_id, position), glyph_utf16_ix) in run
373 .glyphs()
374 .iter()
375 .zip(run.positions().iter())
376 .zip(run.string_indices().iter())
377 {
378 let glyph_utf16_ix = usize::try_from(*glyph_utf16_ix).unwrap();
379 ix_converter.advance_to_utf16_ix(glyph_utf16_ix);
380 glyphs.push(Glyph {
381 id: *glyph_id as GlyphId,
382 position: vec2f(position.x as f32, position.y as f32),
383 index: ix_converter.utf8_ix,
384 is_emoji: self.is_emoji(font_id),
385 });
386 }
387
388 runs.push(Run { font_id, glyphs })
389 }
390
391 let typographic_bounds = line.get_typographic_bounds();
392 LineLayout {
393 width: typographic_bounds.width as f32,
394 ascent: typographic_bounds.ascent as f32,
395 descent: typographic_bounds.descent as f32,
396 runs,
397 font_size,
398 len: text.len(),
399 }
400 }
401
402 fn wrap_line(&self, text: &str, font_id: FontId, font_size: f32, width: f32) -> Vec<usize> {
403 let mut string = CFMutableAttributedString::new();
404 string.replace_str(&CFString::new(text), CFRange::init(0, 0));
405 let cf_range = CFRange::init(0 as isize, text.encode_utf16().count() as isize);
406 let font = &self.fonts[font_id.0];
407 unsafe {
408 string.set_attribute(
409 cf_range,
410 kCTFontAttributeName,
411 &font.native_font().clone_with_font_size(font_size as f64),
412 );
413
414 let typesetter = CTTypesetterCreateWithAttributedString(string.as_concrete_TypeRef());
415 let mut ix_converter = StringIndexConverter::new(text);
416 let mut break_indices = Vec::new();
417 while ix_converter.utf8_ix < text.len() {
418 let utf16_len = CTTypesetterSuggestLineBreak(
419 typesetter,
420 ix_converter.utf16_ix as isize,
421 width as f64,
422 ) as usize;
423 ix_converter.advance_to_utf16_ix(ix_converter.utf16_ix + utf16_len);
424 if ix_converter.utf8_ix >= text.len() {
425 break;
426 }
427 break_indices.push(ix_converter.utf8_ix as usize);
428 }
429 break_indices
430 }
431 }
432}
433
434#[derive(Clone)]
435struct StringIndexConverter<'a> {
436 text: &'a str,
437 utf8_ix: usize,
438 utf16_ix: usize,
439}
440
441impl<'a> StringIndexConverter<'a> {
442 fn new(text: &'a str) -> Self {
443 Self {
444 text,
445 utf8_ix: 0,
446 utf16_ix: 0,
447 }
448 }
449
450 fn advance_to_utf8_ix(&mut self, utf8_target: usize) {
451 for (ix, c) in self.text[self.utf8_ix..].char_indices() {
452 if self.utf8_ix + ix >= utf8_target {
453 self.utf8_ix += ix;
454 return;
455 }
456 self.utf16_ix += c.len_utf16();
457 }
458 self.utf8_ix = self.text.len();
459 }
460
461 fn advance_to_utf16_ix(&mut self, utf16_target: usize) {
462 for (ix, c) in self.text[self.utf8_ix..].char_indices() {
463 if self.utf16_ix >= utf16_target {
464 self.utf8_ix += ix;
465 return;
466 }
467 self.utf16_ix += c.len_utf16();
468 }
469 self.utf8_ix = self.text.len();
470 }
471}
472
473#[repr(C)]
474pub struct __CFTypesetter(c_void);
475
476pub type CTTypesetterRef = *const __CFTypesetter;
477
478#[link(name = "CoreText", kind = "framework")]
479extern "C" {
480 fn CTTypesetterCreateWithAttributedString(string: CFAttributedStringRef) -> CTTypesetterRef;
481
482 fn CTTypesetterSuggestLineBreak(
483 typesetter: CTTypesetterRef,
484 start_index: CFIndex,
485 width: f64,
486 ) -> CFIndex;
487}
488
489#[cfg(test)]
490mod tests {
491 use super::*;
492 use crate::MutableAppContext;
493 use font_kit::properties::{Style, Weight};
494 use platform::FontSystem as _;
495
496 #[crate::test(self, retries = 5)]
497 fn test_layout_str(_: &mut MutableAppContext) {
498 // This is failing intermittently on CI and we don't have time to figure it out
499 let fonts = FontSystem::new();
500 let menlo = fonts.load_family("Menlo").unwrap();
501 let menlo_regular = RunStyle {
502 font_id: fonts.select_font(&menlo, &Properties::new()).unwrap(),
503 color: Default::default(),
504 underline: Default::default(),
505 };
506 let menlo_italic = RunStyle {
507 font_id: fonts
508 .select_font(&menlo, &Properties::new().style(Style::Italic))
509 .unwrap(),
510 color: Default::default(),
511 underline: Default::default(),
512 };
513 let menlo_bold = RunStyle {
514 font_id: fonts
515 .select_font(&menlo, &Properties::new().weight(Weight::BOLD))
516 .unwrap(),
517 color: Default::default(),
518 underline: Default::default(),
519 };
520 assert_ne!(menlo_regular, menlo_italic);
521 assert_ne!(menlo_regular, menlo_bold);
522 assert_ne!(menlo_italic, menlo_bold);
523
524 let line = fonts.layout_line(
525 "hello world",
526 16.0,
527 &[(2, menlo_bold), (4, menlo_italic), (5, menlo_regular)],
528 );
529 assert_eq!(line.runs.len(), 3);
530 assert_eq!(line.runs[0].font_id, menlo_bold.font_id);
531 assert_eq!(line.runs[0].glyphs.len(), 2);
532 assert_eq!(line.runs[1].font_id, menlo_italic.font_id);
533 assert_eq!(line.runs[1].glyphs.len(), 4);
534 assert_eq!(line.runs[2].font_id, menlo_regular.font_id);
535 assert_eq!(line.runs[2].glyphs.len(), 5);
536 }
537
538 #[test]
539 fn test_glyph_offsets() -> anyhow::Result<()> {
540 let fonts = FontSystem::new();
541 let zapfino = fonts.load_family("Zapfino")?;
542 let zapfino_regular = RunStyle {
543 font_id: fonts.select_font(&zapfino, &Properties::new())?,
544 color: Default::default(),
545 underline: Default::default(),
546 };
547 let menlo = fonts.load_family("Menlo")?;
548 let menlo_regular = RunStyle {
549 font_id: fonts.select_font(&menlo, &Properties::new())?,
550 color: Default::default(),
551 underline: Default::default(),
552 };
553
554 let text = "This is, mπre πr less, Zapfino!π";
555 let line = fonts.layout_line(
556 text,
557 16.0,
558 &[
559 (9, zapfino_regular),
560 (13, menlo_regular),
561 (text.len() - 22, zapfino_regular),
562 ],
563 );
564 assert_eq!(
565 line.runs
566 .iter()
567 .flat_map(|r| r.glyphs.iter())
568 .map(|g| g.index)
569 .collect::<Vec<_>>(),
570 vec![0, 2, 4, 5, 7, 8, 9, 10, 14, 15, 16, 17, 21, 22, 23, 24, 26, 27, 28, 29, 36, 37],
571 );
572 Ok(())
573 }
574
575 #[test]
576 #[ignore]
577 fn test_rasterize_glyph() {
578 use std::{fs::File, io::BufWriter, path::Path};
579
580 let fonts = FontSystem::new();
581 let font_ids = fonts.load_family("Fira Code").unwrap();
582 let font_id = fonts.select_font(&font_ids, &Default::default()).unwrap();
583 let glyph_id = fonts.glyph_for_char(font_id, 'G').unwrap();
584
585 const VARIANTS: usize = 1;
586 for i in 0..VARIANTS {
587 let variant = i as f32 / VARIANTS as f32;
588 let (bounds, bytes) = fonts
589 .rasterize_glyph(
590 font_id,
591 16.0,
592 glyph_id,
593 vec2f(variant, variant),
594 2.,
595 RasterizationOptions::Alpha,
596 )
597 .unwrap();
598
599 let name = format!("/Users/as-cii/Desktop/twog-{}.png", i);
600 let path = Path::new(&name);
601 let file = File::create(path).unwrap();
602 let ref mut w = BufWriter::new(file);
603
604 let mut encoder = png::Encoder::new(w, bounds.width() as u32, bounds.height() as u32);
605 encoder.set_color(png::ColorType::Grayscale);
606 encoder.set_depth(png::BitDepth::Eight);
607 let mut writer = encoder.write_header().unwrap();
608 writer.write_image_data(&bytes).unwrap();
609 }
610 }
611
612 #[test]
613 fn test_wrap_line() {
614 let fonts = FontSystem::new();
615 let font_ids = fonts.load_family("Helvetica").unwrap();
616 let font_id = fonts.select_font(&font_ids, &Default::default()).unwrap();
617
618 let line = "one two three four five\n";
619 let wrap_boundaries = fonts.wrap_line(line, font_id, 16., 64.0);
620 assert_eq!(wrap_boundaries, &["one two ".len(), "one two three ".len()]);
621
622 let line = "aaa Ξ±Ξ±Ξ± βββ πππ\n";
623 let wrap_boundaries = fonts.wrap_line(line, font_id, 16., 64.0);
624 assert_eq!(
625 wrap_boundaries,
626 &["aaa Ξ±Ξ±Ξ± ".len(), "aaa Ξ±Ξ±Ξ± βββ ".len(),]
627 );
628 }
629
630 #[test]
631 fn test_layout_line_bom_char() {
632 let fonts = FontSystem::new();
633 let font_ids = fonts.load_family("Helvetica").unwrap();
634 let style = RunStyle {
635 font_id: fonts.select_font(&font_ids, &Default::default()).unwrap(),
636 color: Default::default(),
637 underline: Default::default(),
638 };
639
640 let line = "\u{feff}";
641 let layout = fonts.layout_line(line, 16., &[(line.len(), style)]);
642 assert_eq!(layout.len, line.len());
643 assert!(layout.runs.is_empty());
644
645 let line = "a\u{feff}b";
646 let layout = fonts.layout_line(line, 16., &[(line.len(), style)]);
647 assert_eq!(layout.len, line.len());
648 assert_eq!(layout.runs.len(), 1);
649 assert_eq!(layout.runs[0].glyphs.len(), 2);
650 assert_eq!(layout.runs[0].glyphs[0].id, 68); // a
651 // There's no glyph for \u{feff}
652 assert_eq!(layout.runs[0].glyphs[1].id, 69); // b
653 }
654}