1use crate::{
2 fonts::{FontId, GlyphId, Metrics, Properties},
3 geometry::{
4 rect::{RectF, RectI},
5 transform2d::Transform2F,
6 vector::{vec2f, vec2i, Vector2F},
7 },
8 platform,
9 text_layout::{Glyph, LineLayout, Run, RunStyle},
10};
11use cocoa::appkit::{CGFloat, CGPoint};
12use core_foundation::{
13 array::CFIndex,
14 attributed_string::{CFAttributedStringRef, CFMutableAttributedString},
15 base::{CFRange, TCFType},
16 number::CFNumber,
17 string::CFString,
18};
19use core_graphics::{
20 base::CGGlyph, color_space::CGColorSpace, context::CGContext, geometry::CGAffineTransform,
21};
22use core_text::{line::CTLine, string_attributes::kCTFontAttributeName};
23use font_kit::{
24 canvas::RasterizationOptions, handle::Handle, hinting::HintingOptions, source::SystemSource,
25 sources::mem::MemSource,
26};
27use parking_lot::RwLock;
28use std::{cell::RefCell, char, cmp, convert::TryFrom, ffi::c_void, sync::Arc};
29
30#[allow(non_upper_case_globals)]
31const kCGImageAlphaOnly: u32 = 7;
32
33pub struct FontSystem(RwLock<FontSystemState>);
34
35struct FontSystemState {
36 memory_source: MemSource,
37 system_source: SystemSource,
38 fonts: Vec<font_kit::font::Font>,
39}
40
41impl FontSystem {
42 pub fn new() -> Self {
43 Self(RwLock::new(FontSystemState {
44 memory_source: MemSource::empty(),
45 system_source: SystemSource::new(),
46 fonts: Vec::new(),
47 }))
48 }
49}
50
51impl platform::FontSystem for FontSystem {
52 fn add_fonts(&self, fonts: &[Arc<Vec<u8>>]) -> anyhow::Result<()> {
53 self.0.write().add_fonts(fonts)
54 }
55
56 fn load_family(&self, name: &str) -> anyhow::Result<Vec<FontId>> {
57 self.0.write().load_family(name)
58 }
59
60 fn select_font(&self, font_ids: &[FontId], properties: &Properties) -> anyhow::Result<FontId> {
61 self.0.read().select_font(font_ids, properties)
62 }
63
64 fn font_metrics(&self, font_id: FontId) -> Metrics {
65 self.0.read().font_metrics(font_id)
66 }
67
68 fn typographic_bounds(&self, font_id: FontId, glyph_id: GlyphId) -> anyhow::Result<RectF> {
69 self.0.read().typographic_bounds(font_id, glyph_id)
70 }
71
72 fn glyph_for_char(&self, font_id: FontId, ch: char) -> Option<GlyphId> {
73 self.0.read().glyph_for_char(font_id, ch)
74 }
75
76 fn rasterize_glyph(
77 &self,
78 font_id: FontId,
79 font_size: f32,
80 glyph_id: GlyphId,
81 subpixel_shift: Vector2F,
82 scale_factor: f32,
83 ) -> Option<(RectI, Vec<u8>)> {
84 self.0
85 .read()
86 .rasterize_glyph(font_id, font_size, glyph_id, subpixel_shift, scale_factor)
87 }
88
89 fn layout_line(&self, text: &str, font_size: f32, runs: &[(usize, RunStyle)]) -> LineLayout {
90 self.0.read().layout_line(text, font_size, runs)
91 }
92
93 fn wrap_line(&self, text: &str, font_id: FontId, font_size: f32, width: f32) -> Vec<usize> {
94 self.0.read().wrap_line(text, font_id, font_size, width)
95 }
96}
97
98impl FontSystemState {
99 fn add_fonts(&mut self, fonts: &[Arc<Vec<u8>>]) -> anyhow::Result<()> {
100 self.memory_source.add_fonts(
101 fonts
102 .iter()
103 .map(|bytes| Handle::from_memory(bytes.clone(), 0)),
104 )?;
105 Ok(())
106 }
107
108 fn load_family(&mut self, name: &str) -> anyhow::Result<Vec<FontId>> {
109 let mut font_ids = Vec::new();
110
111 let family = self
112 .memory_source
113 .select_family_by_name(name)
114 .or_else(|_| self.system_source.select_family_by_name(name))?;
115 for font in family.fonts() {
116 let font = font.load()?;
117 font_ids.push(FontId(self.fonts.len()));
118 self.fonts.push(font);
119 }
120 Ok(font_ids)
121 }
122
123 fn select_font(&self, font_ids: &[FontId], properties: &Properties) -> anyhow::Result<FontId> {
124 let candidates = font_ids
125 .iter()
126 .map(|font_id| self.fonts[font_id.0].properties())
127 .collect::<Vec<_>>();
128 let idx = font_kit::matching::find_best_match(&candidates, properties)?;
129 Ok(font_ids[idx])
130 }
131
132 fn font_metrics(&self, font_id: FontId) -> Metrics {
133 self.fonts[font_id.0].metrics()
134 }
135
136 fn typographic_bounds(&self, font_id: FontId, glyph_id: GlyphId) -> anyhow::Result<RectF> {
137 Ok(self.fonts[font_id.0].typographic_bounds(glyph_id)?)
138 }
139
140 fn glyph_for_char(&self, font_id: FontId, ch: char) -> Option<GlyphId> {
141 self.fonts[font_id.0].glyph_for_char(ch)
142 }
143
144 fn rasterize_glyph(
145 &self,
146 font_id: FontId,
147 font_size: f32,
148 glyph_id: GlyphId,
149 subpixel_shift: Vector2F,
150 scale_factor: f32,
151 ) -> Option<(RectI, Vec<u8>)> {
152 let font = &self.fonts[font_id.0];
153 let scale = Transform2F::from_scale(scale_factor);
154 let bounds = font
155 .raster_bounds(
156 glyph_id,
157 font_size,
158 scale,
159 HintingOptions::None,
160 RasterizationOptions::GrayscaleAa,
161 )
162 .ok()?;
163
164 if bounds.width() == 0 || bounds.height() == 0 {
165 None
166 } else {
167 // Make room for subpixel variants.
168 let bounds = RectI::new(bounds.origin(), bounds.size() + vec2i(1, 1));
169 let mut pixels = vec![0; bounds.width() as usize * bounds.height() as usize];
170 let cx = CGContext::create_bitmap_context(
171 Some(pixels.as_mut_ptr() as *mut _),
172 bounds.width() as usize,
173 bounds.height() as usize,
174 8,
175 bounds.width() as usize,
176 &CGColorSpace::create_device_gray(),
177 kCGImageAlphaOnly,
178 );
179
180 // Move the origin to bottom left and account for scaling, this
181 // makes drawing text consistent with the font-kit's raster_bounds.
182 cx.translate(0.0, bounds.height() as CGFloat);
183 let transform = scale.translate(-bounds.origin().to_f32());
184 cx.set_text_matrix(&CGAffineTransform {
185 a: transform.matrix.m11() as CGFloat,
186 b: -transform.matrix.m21() as CGFloat,
187 c: -transform.matrix.m12() as CGFloat,
188 d: transform.matrix.m22() as CGFloat,
189 tx: transform.vector.x() as CGFloat,
190 ty: -transform.vector.y() as CGFloat,
191 });
192
193 cx.set_font(&font.native_font().copy_to_CGFont());
194 cx.set_font_size(font_size as CGFloat);
195 cx.show_glyphs_at_positions(
196 &[glyph_id as CGGlyph],
197 &[CGPoint::new(
198 (subpixel_shift.x() / scale_factor) as CGFloat,
199 (subpixel_shift.y() / scale_factor) as CGFloat,
200 )],
201 );
202
203 Some((bounds, pixels))
204 }
205 }
206
207 fn layout_line(&self, text: &str, font_size: f32, runs: &[(usize, RunStyle)]) -> LineLayout {
208 let font_id_attr_name = CFString::from_static_string("zed_font_id");
209
210 // Construct the attributed string, converting UTF8 ranges to UTF16 ranges.
211 let mut string = CFMutableAttributedString::new();
212 {
213 string.replace_str(&CFString::new(text), CFRange::init(0, 0));
214 let utf16_line_len = string.char_len() as usize;
215
216 let last_run: RefCell<Option<(usize, FontId)>> = Default::default();
217 let font_runs = runs
218 .iter()
219 .filter_map(|(len, style)| {
220 let mut last_run = last_run.borrow_mut();
221 if let Some((last_len, last_font_id)) = last_run.as_mut() {
222 if style.font_id == *last_font_id {
223 *last_len += *len;
224 None
225 } else {
226 let result = (*last_len, *last_font_id);
227 *last_len = *len;
228 *last_font_id = style.font_id;
229 Some(result)
230 }
231 } else {
232 *last_run = Some((*len, style.font_id));
233 None
234 }
235 })
236 .chain(std::iter::from_fn(|| last_run.borrow_mut().take()));
237
238 let mut ix_converter = StringIndexConverter::new(text);
239 for (run_len, font_id) in font_runs {
240 let utf8_end = ix_converter.utf8_ix + run_len;
241 let utf16_start = ix_converter.utf16_ix;
242
243 if utf16_start >= utf16_line_len {
244 break;
245 }
246
247 ix_converter.advance_to_utf8_ix(utf8_end);
248 let utf16_end = cmp::min(ix_converter.utf16_ix, utf16_line_len);
249
250 let cf_range =
251 CFRange::init(utf16_start as isize, (utf16_end - utf16_start) as isize);
252 let font = &self.fonts[font_id.0];
253 unsafe {
254 string.set_attribute(
255 cf_range,
256 kCTFontAttributeName,
257 &font.native_font().clone_with_font_size(font_size as f64),
258 );
259 string.set_attribute(
260 cf_range,
261 font_id_attr_name.as_concrete_TypeRef(),
262 &CFNumber::from(font_id.0 as i64),
263 );
264 }
265
266 if utf16_end == utf16_line_len {
267 break;
268 }
269 }
270 }
271
272 // Retrieve the glyphs from the shaped line, converting UTF16 offsets to UTF8 offsets.
273 let line = CTLine::new_with_attributed_string(string.as_concrete_TypeRef());
274
275 let mut runs = Vec::new();
276 for run in line.glyph_runs().into_iter() {
277 let font_id = FontId(
278 run.attributes()
279 .unwrap()
280 .get(&font_id_attr_name)
281 .downcast::<CFNumber>()
282 .unwrap()
283 .to_i64()
284 .unwrap() as usize,
285 );
286
287 let mut ix_converter = StringIndexConverter::new(text);
288 let mut glyphs = Vec::new();
289 for ((glyph_id, position), glyph_utf16_ix) in run
290 .glyphs()
291 .iter()
292 .zip(run.positions().iter())
293 .zip(run.string_indices().iter())
294 {
295 let glyph_utf16_ix = usize::try_from(*glyph_utf16_ix).unwrap();
296 ix_converter.advance_to_utf16_ix(glyph_utf16_ix);
297 glyphs.push(Glyph {
298 id: *glyph_id as GlyphId,
299 position: vec2f(position.x as f32, position.y as f32),
300 index: ix_converter.utf8_ix,
301 });
302 }
303
304 runs.push(Run { font_id, glyphs })
305 }
306
307 let typographic_bounds = line.get_typographic_bounds();
308 LineLayout {
309 width: typographic_bounds.width as f32,
310 ascent: typographic_bounds.ascent as f32,
311 descent: typographic_bounds.descent as f32,
312 runs,
313 font_size,
314 len: text.len(),
315 }
316 }
317
318 fn wrap_line(&self, text: &str, font_id: FontId, font_size: f32, width: f32) -> Vec<usize> {
319 let mut string = CFMutableAttributedString::new();
320 string.replace_str(&CFString::new(text), CFRange::init(0, 0));
321 let cf_range = CFRange::init(0 as isize, text.encode_utf16().count() as isize);
322 let font = &self.fonts[font_id.0];
323 unsafe {
324 string.set_attribute(
325 cf_range,
326 kCTFontAttributeName,
327 &font.native_font().clone_with_font_size(font_size as f64),
328 );
329
330 let typesetter = CTTypesetterCreateWithAttributedString(string.as_concrete_TypeRef());
331 let mut ix_converter = StringIndexConverter::new(text);
332 let mut break_indices = Vec::new();
333 while ix_converter.utf8_ix < text.len() {
334 let utf16_len = CTTypesetterSuggestLineBreak(
335 typesetter,
336 ix_converter.utf16_ix as isize,
337 width as f64,
338 ) as usize;
339 ix_converter.advance_to_utf16_ix(ix_converter.utf16_ix + utf16_len);
340 if ix_converter.utf8_ix >= text.len() {
341 break;
342 }
343 break_indices.push(ix_converter.utf8_ix as usize);
344 }
345 break_indices
346 }
347 }
348}
349
350#[derive(Clone)]
351struct StringIndexConverter<'a> {
352 text: &'a str,
353 utf8_ix: usize,
354 utf16_ix: usize,
355}
356
357impl<'a> StringIndexConverter<'a> {
358 fn new(text: &'a str) -> Self {
359 Self {
360 text,
361 utf8_ix: 0,
362 utf16_ix: 0,
363 }
364 }
365
366 fn advance_to_utf8_ix(&mut self, utf8_target: usize) {
367 for (ix, c) in self.text[self.utf8_ix..].char_indices() {
368 if self.utf8_ix + ix >= utf8_target {
369 self.utf8_ix += ix;
370 return;
371 }
372 self.utf16_ix += c.len_utf16();
373 }
374 self.utf8_ix = self.text.len();
375 }
376
377 fn advance_to_utf16_ix(&mut self, utf16_target: usize) {
378 for (ix, c) in self.text[self.utf8_ix..].char_indices() {
379 if self.utf16_ix >= utf16_target {
380 self.utf8_ix += ix;
381 return;
382 }
383 self.utf16_ix += c.len_utf16();
384 }
385 self.utf8_ix = self.text.len();
386 }
387}
388
389#[repr(C)]
390pub struct __CFTypesetter(c_void);
391
392pub type CTTypesetterRef = *const __CFTypesetter;
393
394#[link(name = "CoreText", kind = "framework")]
395extern "C" {
396 fn CTTypesetterCreateWithAttributedString(string: CFAttributedStringRef) -> CTTypesetterRef;
397
398 fn CTTypesetterSuggestLineBreak(
399 typesetter: CTTypesetterRef,
400 start_index: CFIndex,
401 width: f64,
402 ) -> CFIndex;
403}
404
405#[cfg(test)]
406mod tests {
407 use super::*;
408 use crate::MutableAppContext;
409 use font_kit::properties::{Style, Weight};
410 use platform::FontSystem as _;
411
412 #[crate::test(self, retries = 5)]
413 fn test_layout_str(_: &mut MutableAppContext) {
414 // This is failing intermittently on CI and we don't have time to figure it out
415 let fonts = FontSystem::new();
416 let menlo = fonts.load_family("Menlo").unwrap();
417 let menlo_regular = RunStyle {
418 font_id: fonts.select_font(&menlo, &Properties::new()).unwrap(),
419 color: Default::default(),
420 underline: None,
421 };
422 let menlo_italic = RunStyle {
423 font_id: fonts
424 .select_font(&menlo, &Properties::new().style(Style::Italic))
425 .unwrap(),
426 color: Default::default(),
427 underline: None,
428 };
429 let menlo_bold = RunStyle {
430 font_id: fonts
431 .select_font(&menlo, &Properties::new().weight(Weight::BOLD))
432 .unwrap(),
433 color: Default::default(),
434 underline: None,
435 };
436 assert_ne!(menlo_regular, menlo_italic);
437 assert_ne!(menlo_regular, menlo_bold);
438 assert_ne!(menlo_italic, menlo_bold);
439
440 let line = fonts.layout_line(
441 "hello world",
442 16.0,
443 &[(2, menlo_bold), (4, menlo_italic), (5, menlo_regular)],
444 );
445 assert_eq!(line.runs.len(), 3);
446 assert_eq!(line.runs[0].font_id, menlo_bold.font_id);
447 assert_eq!(line.runs[0].glyphs.len(), 2);
448 assert_eq!(line.runs[1].font_id, menlo_italic.font_id);
449 assert_eq!(line.runs[1].glyphs.len(), 4);
450 assert_eq!(line.runs[2].font_id, menlo_regular.font_id);
451 assert_eq!(line.runs[2].glyphs.len(), 5);
452 }
453
454 #[test]
455 fn test_glyph_offsets() -> anyhow::Result<()> {
456 let fonts = FontSystem::new();
457 let zapfino = fonts.load_family("Zapfino")?;
458 let zapfino_regular = RunStyle {
459 font_id: fonts.select_font(&zapfino, &Properties::new())?,
460 color: Default::default(),
461 underline: None,
462 };
463 let menlo = fonts.load_family("Menlo")?;
464 let menlo_regular = RunStyle {
465 font_id: fonts.select_font(&menlo, &Properties::new())?,
466 color: Default::default(),
467 underline: None,
468 };
469
470 let text = "This is, mπre πr less, Zapfino!π";
471 let line = fonts.layout_line(
472 text,
473 16.0,
474 &[
475 (9, zapfino_regular),
476 (13, menlo_regular),
477 (text.len() - 22, zapfino_regular),
478 ],
479 );
480 assert_eq!(
481 line.runs
482 .iter()
483 .flat_map(|r| r.glyphs.iter())
484 .map(|g| g.index)
485 .collect::<Vec<_>>(),
486 vec![0, 2, 4, 5, 7, 8, 9, 10, 14, 15, 16, 17, 21, 22, 23, 24, 26, 27, 28, 29, 36, 37],
487 );
488 Ok(())
489 }
490
491 #[test]
492 #[ignore]
493 fn test_rasterize_glyph() {
494 use std::{fs::File, io::BufWriter, path::Path};
495
496 let fonts = FontSystem::new();
497 let font_ids = fonts.load_family("Fira Code").unwrap();
498 let font_id = fonts.select_font(&font_ids, &Default::default()).unwrap();
499 let glyph_id = fonts.glyph_for_char(font_id, 'G').unwrap();
500
501 const VARIANTS: usize = 1;
502 for i in 0..VARIANTS {
503 let variant = i as f32 / VARIANTS as f32;
504 let (bounds, bytes) = fonts
505 .rasterize_glyph(font_id, 16.0, glyph_id, vec2f(variant, variant), 2.)
506 .unwrap();
507
508 let name = format!("/Users/as-cii/Desktop/twog-{}.png", i);
509 let path = Path::new(&name);
510 let file = File::create(path).unwrap();
511 let ref mut w = BufWriter::new(file);
512
513 let mut encoder = png::Encoder::new(w, bounds.width() as u32, bounds.height() as u32);
514 encoder.set_color(png::ColorType::Grayscale);
515 encoder.set_depth(png::BitDepth::Eight);
516 let mut writer = encoder.write_header().unwrap();
517 writer.write_image_data(&bytes).unwrap();
518 }
519 }
520
521 #[test]
522 fn test_wrap_line() {
523 let fonts = FontSystem::new();
524 let font_ids = fonts.load_family("Helvetica").unwrap();
525 let font_id = fonts.select_font(&font_ids, &Default::default()).unwrap();
526
527 let line = "one two three four five\n";
528 let wrap_boundaries = fonts.wrap_line(line, font_id, 16., 64.0);
529 assert_eq!(wrap_boundaries, &["one two ".len(), "one two three ".len()]);
530
531 let line = "aaa Ξ±Ξ±Ξ± βββ πππ\n";
532 let wrap_boundaries = fonts.wrap_line(line, font_id, 16., 64.0);
533 assert_eq!(
534 wrap_boundaries,
535 &["aaa Ξ±Ξ±Ξ± ".len(), "aaa Ξ±Ξ±Ξ± βββ ".len(),]
536 );
537 }
538
539 #[test]
540 fn test_layout_line_bom_char() {
541 let fonts = FontSystem::new();
542 let font_ids = fonts.load_family("Helvetica").unwrap();
543 let style = RunStyle {
544 font_id: fonts.select_font(&font_ids, &Default::default()).unwrap(),
545 color: Default::default(),
546 underline: None,
547 };
548
549 let line = "\u{feff}";
550 let layout = fonts.layout_line(line, 16., &[(line.len(), style)]);
551 assert_eq!(layout.len, line.len());
552 assert!(layout.runs.is_empty());
553
554 let line = "a\u{feff}b";
555 let layout = fonts.layout_line(line, 16., &[(line.len(), style)]);
556 assert_eq!(layout.len, line.len());
557 assert_eq!(layout.runs.len(), 1);
558 assert_eq!(layout.runs[0].glyphs.len(), 2);
559 assert_eq!(layout.runs[0].glyphs[0].id, 68); // a
560 // There's no glyph for \u{feff}
561 assert_eq!(layout.runs[0].glyphs[1].id, 69); // b
562 }
563}