text_system.rs

  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    number::CFNumber,
 14    string::CFString,
 15};
 16use core_graphics::{
 17    base::{kCGImageAlphaPremultipliedLast, CGGlyph},
 18    color_space::CGColorSpace,
 19    context::CGContext,
 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::{char, cmp, convert::TryFrom, ffi::c_void, sync::Arc};
 46
 47use super::open_type;
 48
 49#[allow(non_upper_case_globals)]
 50const kCGImageAlphaOnly: u32 = 7;
 51
 52pub(crate) struct MacTextSystem(RwLock<MacTextSystemState>);
 53
 54struct MacTextSystemState {
 55    memory_source: MemSource,
 56    system_source: SystemSource,
 57    fonts: Vec<FontKitFont>,
 58    font_selections: HashMap<Font, FontId>,
 59    font_ids_by_postscript_name: HashMap<String, FontId>,
 60    font_ids_by_family_name: HashMap<SharedString, SmallVec<[FontId; 4]>>,
 61    postscript_names_by_font_id: HashMap<FontId, String>,
 62}
 63
 64impl MacTextSystem {
 65    pub(crate) fn new() -> Self {
 66        Self(RwLock::new(MacTextSystemState {
 67            memory_source: MemSource::empty(),
 68            system_source: SystemSource::new(),
 69            fonts: Vec::new(),
 70            font_selections: HashMap::default(),
 71            font_ids_by_postscript_name: HashMap::default(),
 72            font_ids_by_family_name: HashMap::default(),
 73            postscript_names_by_font_id: HashMap::default(),
 74        }))
 75    }
 76}
 77
 78impl Default for MacTextSystem {
 79    fn default() -> Self {
 80        Self::new()
 81    }
 82}
 83
 84impl PlatformTextSystem for MacTextSystem {
 85    fn add_fonts(&self, fonts: &[Arc<Vec<u8>>]) -> Result<()> {
 86        self.0.write().add_fonts(fonts)
 87    }
 88
 89    fn all_font_names(&self) -> Vec<String> {
 90        let collection = core_text::font_collection::create_for_all_families();
 91        let Some(descriptors) = collection.get_descriptors() else {
 92            return Vec::new();
 93        };
 94        let mut names = BTreeSet::new();
 95        for descriptor in descriptors.into_iter() {
 96            names.extend(lenient_font_attributes::family_name(&descriptor));
 97        }
 98        if let Ok(fonts_in_memory) = self.0.read().memory_source.all_families() {
 99            names.extend(fonts_in_memory);
100        }
101        names.into_iter().collect()
102    }
103
104    fn all_font_families(&self) -> Vec<String> {
105        self.0
106            .read()
107            .system_source
108            .all_families()
109            .expect("core text should never return an error")
110    }
111
112    fn font_id(&self, font: &Font) -> Result<FontId> {
113        let lock = self.0.upgradable_read();
114        if let Some(font_id) = lock.font_selections.get(font) {
115            Ok(*font_id)
116        } else {
117            let mut lock = RwLockUpgradableReadGuard::upgrade(lock);
118            let candidates = if let Some(font_ids) = lock.font_ids_by_family_name.get(&font.family)
119            {
120                font_ids.as_slice()
121            } else {
122                let font_ids = lock.load_family(&font.family, font.features)?;
123                lock.font_ids_by_family_name
124                    .insert(font.family.clone(), font_ids);
125                lock.font_ids_by_family_name[&font.family].as_ref()
126            };
127
128            let candidate_properties = candidates
129                .iter()
130                .map(|font_id| lock.fonts[font_id.0].properties())
131                .collect::<SmallVec<[_; 4]>>();
132
133            let ix = font_kit::matching::find_best_match(
134                &candidate_properties,
135                &font_kit::properties::Properties {
136                    style: font.style.into(),
137                    weight: font.weight.into(),
138                    stretch: Default::default(),
139                },
140            )?;
141
142            let font_id = candidates[ix];
143            lock.font_selections.insert(font.clone(), font_id);
144            Ok(font_id)
145        }
146    }
147
148    fn font_metrics(&self, font_id: FontId) -> FontMetrics {
149        self.0.read().fonts[font_id.0].metrics().into()
150    }
151
152    fn typographic_bounds(&self, font_id: FontId, glyph_id: GlyphId) -> Result<Bounds<f32>> {
153        Ok(self.0.read().fonts[font_id.0]
154            .typographic_bounds(glyph_id.0)?
155            .into())
156    }
157
158    fn advance(&self, font_id: FontId, glyph_id: GlyphId) -> Result<Size<f32>> {
159        self.0.read().advance(font_id, glyph_id)
160    }
161
162    fn glyph_for_char(&self, font_id: FontId, ch: char) -> Option<GlyphId> {
163        self.0.read().glyph_for_char(font_id, ch)
164    }
165
166    fn glyph_raster_bounds(&self, params: &RenderGlyphParams) -> Result<Bounds<DevicePixels>> {
167        self.0.read().raster_bounds(params)
168    }
169
170    fn rasterize_glyph(
171        &self,
172        glyph_id: &RenderGlyphParams,
173        raster_bounds: Bounds<DevicePixels>,
174    ) -> Result<(Size<DevicePixels>, Vec<u8>)> {
175        self.0.read().rasterize_glyph(glyph_id, raster_bounds)
176    }
177
178    fn layout_line(&self, text: &str, font_size: Pixels, font_runs: &[FontRun]) -> LineLayout {
179        self.0.write().layout_line(text, font_size, font_runs)
180    }
181
182    fn wrap_line(
183        &self,
184        text: &str,
185        font_id: FontId,
186        font_size: Pixels,
187        width: Pixels,
188    ) -> Vec<usize> {
189        self.0.read().wrap_line(text, font_id, font_size, width)
190    }
191}
192
193impl MacTextSystemState {
194    fn add_fonts(&mut self, fonts: &[Arc<Vec<u8>>]) -> Result<()> {
195        self.memory_source.add_fonts(
196            fonts
197                .iter()
198                .map(|bytes| Handle::from_memory(bytes.clone(), 0)),
199        )?;
200        Ok(())
201    }
202
203    fn load_family(
204        &mut self,
205        name: &SharedString,
206        features: FontFeatures,
207    ) -> Result<SmallVec<[FontId; 4]>> {
208        let mut font_ids = SmallVec::new();
209        let family = self
210            .memory_source
211            .select_family_by_name(name.as_ref())
212            .or_else(|_| self.system_source.select_family_by_name(name.as_ref()))?;
213        for font in family.fonts() {
214            let mut font = font.load()?;
215            open_type::apply_features(&mut font, features);
216            let Some(_) = font.glyph_for_char('m') else {
217                continue;
218            };
219            // We've seen a number of panics in production caused by calling font.properties()
220            // which unwraps a downcast to CFNumber. This is an attempt to avoid the panic,
221            // and to try and identify the incalcitrant font.
222            let traits = font.native_font().all_traits();
223            if unsafe {
224                !(traits
225                    .get(kCTFontSymbolicTrait)
226                    .downcast::<CFNumber>()
227                    .is_some()
228                    && traits
229                        .get(kCTFontWidthTrait)
230                        .downcast::<CFNumber>()
231                        .is_some()
232                    && traits
233                        .get(kCTFontWeightTrait)
234                        .downcast::<CFNumber>()
235                        .is_some()
236                    && traits
237                        .get(kCTFontSlantTrait)
238                        .downcast::<CFNumber>()
239                        .is_some())
240            } {
241                log::error!(
242                    "Failed to read traits for font {:?}",
243                    font.postscript_name().unwrap()
244                );
245                continue;
246            }
247
248            let font_id = FontId(self.fonts.len());
249            font_ids.push(font_id);
250            let postscript_name = font.postscript_name().unwrap();
251            self.font_ids_by_postscript_name
252                .insert(postscript_name.clone(), font_id);
253            self.postscript_names_by_font_id
254                .insert(font_id, postscript_name);
255            self.fonts.push(font);
256        }
257        Ok(font_ids)
258    }
259
260    fn advance(&self, font_id: FontId, glyph_id: GlyphId) -> Result<Size<f32>> {
261        Ok(self.fonts[font_id.0].advance(glyph_id.0)?.into())
262    }
263
264    fn glyph_for_char(&self, font_id: FontId, ch: char) -> Option<GlyphId> {
265        self.fonts[font_id.0].glyph_for_char(ch).map(GlyphId)
266    }
267
268    fn id_for_native_font(&mut self, requested_font: CTFont) -> FontId {
269        let postscript_name = requested_font.postscript_name();
270        if let Some(font_id) = self.font_ids_by_postscript_name.get(&postscript_name) {
271            *font_id
272        } else {
273            let font_id = FontId(self.fonts.len());
274            self.font_ids_by_postscript_name
275                .insert(postscript_name.clone(), font_id);
276            self.postscript_names_by_font_id
277                .insert(font_id, postscript_name);
278            self.fonts
279                .push(font_kit::font::Font::from_core_graphics_font(
280                    requested_font.copy_to_CGFont(),
281                ));
282            font_id
283        }
284    }
285
286    fn is_emoji(&self, font_id: FontId) -> bool {
287        self.postscript_names_by_font_id
288            .get(&font_id)
289            .map_or(false, |postscript_name| {
290                postscript_name == "AppleColorEmoji"
291            })
292    }
293
294    fn raster_bounds(&self, params: &RenderGlyphParams) -> Result<Bounds<DevicePixels>> {
295        let font = &self.fonts[params.font_id.0];
296        let scale = Transform2F::from_scale(params.scale_factor);
297        Ok(font
298            .raster_bounds(
299                params.glyph_id.0,
300                params.font_size.into(),
301                scale,
302                HintingOptions::None,
303                font_kit::canvas::RasterizationOptions::GrayscaleAa,
304            )?
305            .into())
306    }
307
308    fn rasterize_glyph(
309        &self,
310        params: &RenderGlyphParams,
311        glyph_bounds: Bounds<DevicePixels>,
312    ) -> Result<(Size<DevicePixels>, Vec<u8>)> {
313        if glyph_bounds.size.width.0 == 0 || glyph_bounds.size.height.0 == 0 {
314            Err(anyhow!("glyph bounds are empty"))
315        } else {
316            // Add an extra pixel when the subpixel variant isn't zero to make room for anti-aliasing.
317            let mut bitmap_size = glyph_bounds.size;
318            if params.subpixel_variant.x > 0 {
319                bitmap_size.width += DevicePixels(1);
320            }
321            if params.subpixel_variant.y > 0 {
322                bitmap_size.height += DevicePixels(1);
323            }
324            let bitmap_size = bitmap_size;
325
326            let mut bytes;
327            let cx;
328            if params.is_emoji {
329                bytes = vec![0; bitmap_size.width.0 as usize * 4 * bitmap_size.height.0 as usize];
330                cx = CGContext::create_bitmap_context(
331                    Some(bytes.as_mut_ptr() as *mut _),
332                    bitmap_size.width.0 as usize,
333                    bitmap_size.height.0 as usize,
334                    8,
335                    bitmap_size.width.0 as usize * 4,
336                    &CGColorSpace::create_device_rgb(),
337                    kCGImageAlphaPremultipliedLast,
338                );
339            } else {
340                bytes = vec![0; bitmap_size.width.0 as usize * bitmap_size.height.0 as usize];
341                cx = CGContext::create_bitmap_context(
342                    Some(bytes.as_mut_ptr() as *mut _),
343                    bitmap_size.width.0 as usize,
344                    bitmap_size.height.0 as usize,
345                    8,
346                    bitmap_size.width.0 as usize,
347                    &CGColorSpace::create_device_gray(),
348                    kCGImageAlphaOnly,
349                );
350            }
351
352            // Move the origin to bottom left and account for scaling, this
353            // makes drawing text consistent with the font-kit's raster_bounds.
354            cx.translate(
355                -glyph_bounds.origin.x.0 as CGFloat,
356                (glyph_bounds.origin.y.0 + glyph_bounds.size.height.0) as CGFloat,
357            );
358            cx.scale(
359                params.scale_factor as CGFloat,
360                params.scale_factor as CGFloat,
361            );
362
363            let subpixel_shift = params
364                .subpixel_variant
365                .map(|v| v as f32 / SUBPIXEL_VARIANTS as f32);
366            cx.set_allows_font_subpixel_positioning(true);
367            cx.set_should_subpixel_position_fonts(true);
368            cx.set_allows_font_subpixel_quantization(false);
369            cx.set_should_subpixel_quantize_fonts(false);
370            self.fonts[params.font_id.0]
371                .native_font()
372                .clone_with_font_size(f32::from(params.font_size) as CGFloat)
373                .draw_glyphs(
374                    &[params.glyph_id.0 as CGGlyph],
375                    &[CGPoint::new(
376                        (subpixel_shift.x / params.scale_factor) as CGFloat,
377                        (subpixel_shift.y / params.scale_factor) as CGFloat,
378                    )],
379                    cx,
380                );
381
382            if params.is_emoji {
383                // Convert from RGBA with premultiplied alpha to BGRA with straight alpha.
384                for pixel in bytes.chunks_exact_mut(4) {
385                    pixel.swap(0, 2);
386                    let a = pixel[3] as f32 / 255.;
387                    pixel[0] = (pixel[0] as f32 / a) as u8;
388                    pixel[1] = (pixel[1] as f32 / a) as u8;
389                    pixel[2] = (pixel[2] as f32 / a) as u8;
390                }
391            }
392
393            Ok((bitmap_size, bytes))
394        }
395    }
396
397    fn layout_line(&mut self, text: &str, font_size: Pixels, font_runs: &[FontRun]) -> LineLayout {
398        // Construct the attributed string, converting UTF8 ranges to UTF16 ranges.
399        let mut string = CFMutableAttributedString::new();
400        {
401            string.replace_str(&CFString::new(text), CFRange::init(0, 0));
402            let utf16_line_len = string.char_len() as usize;
403
404            let mut ix_converter = StringIndexConverter::new(text);
405            for run in font_runs {
406                let utf8_end = ix_converter.utf8_ix + run.len;
407                let utf16_start = ix_converter.utf16_ix;
408
409                if utf16_start >= utf16_line_len {
410                    break;
411                }
412
413                ix_converter.advance_to_utf8_ix(utf8_end);
414                let utf16_end = cmp::min(ix_converter.utf16_ix, utf16_line_len);
415
416                let cf_range =
417                    CFRange::init(utf16_start as isize, (utf16_end - utf16_start) as isize);
418
419                let font: &FontKitFont = &self.fonts[run.font_id.0];
420                unsafe {
421                    string.set_attribute(
422                        cf_range,
423                        kCTFontAttributeName,
424                        &font.native_font().clone_with_font_size(font_size.into()),
425                    );
426                }
427
428                if utf16_end == utf16_line_len {
429                    break;
430                }
431            }
432        }
433
434        // Retrieve the glyphs from the shaped line, converting UTF16 offsets to UTF8 offsets.
435        let line = CTLine::new_with_attributed_string(string.as_concrete_TypeRef());
436
437        let mut runs = Vec::new();
438        for run in line.glyph_runs().into_iter() {
439            let attributes = run.attributes().unwrap();
440            let font = unsafe {
441                attributes
442                    .get(kCTFontAttributeName)
443                    .downcast::<CTFont>()
444                    .unwrap()
445            };
446            let font_id = self.id_for_native_font(font);
447
448            let mut ix_converter = StringIndexConverter::new(text);
449            let mut glyphs = SmallVec::new();
450            for ((glyph_id, position), glyph_utf16_ix) in run
451                .glyphs()
452                .iter()
453                .zip(run.positions().iter())
454                .zip(run.string_indices().iter())
455            {
456                let glyph_utf16_ix = usize::try_from(*glyph_utf16_ix).unwrap();
457                ix_converter.advance_to_utf16_ix(glyph_utf16_ix);
458                glyphs.push(ShapedGlyph {
459                    id: GlyphId(*glyph_id as u32),
460                    position: point(position.x as f32, position.y as f32).map(px),
461                    index: ix_converter.utf8_ix,
462                    is_emoji: self.is_emoji(font_id),
463                });
464            }
465
466            runs.push(ShapedRun { font_id, glyphs })
467        }
468
469        let typographic_bounds = line.get_typographic_bounds();
470        LineLayout {
471            runs,
472            font_size,
473            width: typographic_bounds.width.into(),
474            ascent: typographic_bounds.ascent.into(),
475            descent: typographic_bounds.descent.into(),
476            len: text.len(),
477        }
478    }
479
480    fn wrap_line(
481        &self,
482        text: &str,
483        font_id: FontId,
484        font_size: Pixels,
485        width: Pixels,
486    ) -> Vec<usize> {
487        let mut string = CFMutableAttributedString::new();
488        string.replace_str(&CFString::new(text), CFRange::init(0, 0));
489        let cf_range = CFRange::init(0, text.encode_utf16().count() as isize);
490        let font = &self.fonts[font_id.0];
491        unsafe {
492            string.set_attribute(
493                cf_range,
494                kCTFontAttributeName,
495                &font.native_font().clone_with_font_size(font_size.into()),
496            );
497
498            let typesetter = CTTypesetterCreateWithAttributedString(string.as_concrete_TypeRef());
499            let mut ix_converter = StringIndexConverter::new(text);
500            let mut break_indices = Vec::new();
501            while ix_converter.utf8_ix < text.len() {
502                let utf16_len = CTTypesetterSuggestLineBreak(
503                    typesetter,
504                    ix_converter.utf16_ix as isize,
505                    width.into(),
506                ) as usize;
507                ix_converter.advance_to_utf16_ix(ix_converter.utf16_ix + utf16_len);
508                if ix_converter.utf8_ix >= text.len() {
509                    break;
510                }
511                break_indices.push(ix_converter.utf8_ix);
512            }
513            break_indices
514        }
515    }
516}
517
518#[derive(Clone)]
519struct StringIndexConverter<'a> {
520    text: &'a str,
521    utf8_ix: usize,
522    utf16_ix: usize,
523}
524
525impl<'a> StringIndexConverter<'a> {
526    fn new(text: &'a str) -> Self {
527        Self {
528            text,
529            utf8_ix: 0,
530            utf16_ix: 0,
531        }
532    }
533
534    fn advance_to_utf8_ix(&mut self, utf8_target: usize) {
535        for (ix, c) in self.text[self.utf8_ix..].char_indices() {
536            if self.utf8_ix + ix >= utf8_target {
537                self.utf8_ix += ix;
538                return;
539            }
540            self.utf16_ix += c.len_utf16();
541        }
542        self.utf8_ix = self.text.len();
543    }
544
545    fn advance_to_utf16_ix(&mut self, utf16_target: usize) {
546        for (ix, c) in self.text[self.utf8_ix..].char_indices() {
547            if self.utf16_ix >= utf16_target {
548                self.utf8_ix += ix;
549                return;
550            }
551            self.utf16_ix += c.len_utf16();
552        }
553        self.utf8_ix = self.text.len();
554    }
555}
556
557#[repr(C)]
558pub(crate) struct __CFTypesetter(c_void);
559
560type CTTypesetterRef = *const __CFTypesetter;
561
562#[link(name = "CoreText", kind = "framework")]
563extern "C" {
564    fn CTTypesetterCreateWithAttributedString(string: CFAttributedStringRef) -> CTTypesetterRef;
565
566    fn CTTypesetterSuggestLineBreak(
567        typesetter: CTTypesetterRef,
568        start_index: CFIndex,
569        width: f64,
570    ) -> CFIndex;
571}
572
573impl From<Metrics> for FontMetrics {
574    fn from(metrics: Metrics) -> Self {
575        FontMetrics {
576            units_per_em: metrics.units_per_em,
577            ascent: metrics.ascent,
578            descent: metrics.descent,
579            line_gap: metrics.line_gap,
580            underline_position: metrics.underline_position,
581            underline_thickness: metrics.underline_thickness,
582            cap_height: metrics.cap_height,
583            x_height: metrics.x_height,
584            bounding_box: metrics.bounding_box.into(),
585        }
586    }
587}
588
589impl From<RectF> for Bounds<f32> {
590    fn from(rect: RectF) -> Self {
591        Bounds {
592            origin: point(rect.origin_x(), rect.origin_y()),
593            size: size(rect.width(), rect.height()),
594        }
595    }
596}
597
598impl From<RectI> for Bounds<DevicePixels> {
599    fn from(rect: RectI) -> Self {
600        Bounds {
601            origin: point(DevicePixels(rect.origin_x()), DevicePixels(rect.origin_y())),
602            size: size(DevicePixels(rect.width()), DevicePixels(rect.height())),
603        }
604    }
605}
606
607impl From<Vector2I> for Size<DevicePixels> {
608    fn from(value: Vector2I) -> Self {
609        size(value.x().into(), value.y().into())
610    }
611}
612
613impl From<RectI> for Bounds<i32> {
614    fn from(rect: RectI) -> Self {
615        Bounds {
616            origin: point(rect.origin_x(), rect.origin_y()),
617            size: size(rect.width(), rect.height()),
618        }
619    }
620}
621
622impl From<Point<u32>> for Vector2I {
623    fn from(size: Point<u32>) -> Self {
624        Vector2I::new(size.x as i32, size.y as i32)
625    }
626}
627
628impl From<Vector2F> for Size<f32> {
629    fn from(vec: Vector2F) -> Self {
630        size(vec.x(), vec.y())
631    }
632}
633
634impl From<FontWeight> for FontkitWeight {
635    fn from(value: FontWeight) -> Self {
636        FontkitWeight(value.0)
637    }
638}
639
640impl From<FontStyle> for FontkitStyle {
641    fn from(style: FontStyle) -> Self {
642        match style {
643            FontStyle::Normal => FontkitStyle::Normal,
644            FontStyle::Italic => FontkitStyle::Italic,
645            FontStyle::Oblique => FontkitStyle::Oblique,
646        }
647    }
648}
649
650// Some fonts may have no attributest despite `core_text` requiring them (and panicking).
651// This is the same version as `core_text` has without `expect` calls.
652mod lenient_font_attributes {
653    use core_foundation::{
654        base::{CFRetain, CFType, TCFType},
655        string::{CFString, CFStringRef},
656    };
657    use core_text::font_descriptor::{
658        kCTFontFamilyNameAttribute, CTFontDescriptor, CTFontDescriptorCopyAttribute,
659    };
660
661    pub fn family_name(descriptor: &CTFontDescriptor) -> Option<String> {
662        unsafe { get_string_attribute(descriptor, kCTFontFamilyNameAttribute) }
663    }
664
665    fn get_string_attribute(
666        descriptor: &CTFontDescriptor,
667        attribute: CFStringRef,
668    ) -> Option<String> {
669        unsafe {
670            let value = CTFontDescriptorCopyAttribute(descriptor.as_concrete_TypeRef(), attribute);
671            if value.is_null() {
672                return None;
673            }
674
675            let value = CFType::wrap_under_create_rule(value);
676            assert!(value.instance_of::<CFString>());
677            let s = wrap_under_get_rule(value.as_CFTypeRef() as CFStringRef);
678            Some(s.to_string())
679        }
680    }
681
682    unsafe fn wrap_under_get_rule(reference: CFStringRef) -> CFString {
683        assert!(!reference.is_null(), "Attempted to create a NULL object.");
684        let reference = CFRetain(reference as *const ::std::os::raw::c_void) as CFStringRef;
685        TCFType::wrap_under_create_rule(reference)
686    }
687}
688
689#[cfg(test)]
690mod tests {
691    use crate::{font, px, FontRun, GlyphId, MacTextSystem, PlatformTextSystem};
692
693    #[test]
694    fn test_wrap_line() {
695        let fonts = MacTextSystem::new();
696        let font_id = fonts.font_id(&font("Helvetica")).unwrap();
697
698        let line = "one two three four five\n";
699        let wrap_boundaries = fonts.wrap_line(line, font_id, px(16.), px(64.0));
700        assert_eq!(wrap_boundaries, &["one two ".len(), "one two three ".len()]);
701
702        let line = "aaa ααα ✋✋✋ 🎉🎉🎉\n";
703        let wrap_boundaries = fonts.wrap_line(line, font_id, px(16.), px(64.0));
704        assert_eq!(
705            wrap_boundaries,
706            &["aaa ααα ".len(), "aaa ααα ✋✋✋ ".len(),]
707        );
708    }
709
710    #[test]
711    fn test_layout_line_bom_char() {
712        let fonts = MacTextSystem::new();
713        let font_id = fonts.font_id(&font("Helvetica")).unwrap();
714        let line = "\u{feff}";
715        let mut style = FontRun {
716            font_id,
717            len: line.len(),
718        };
719
720        let layout = fonts.layout_line(line, px(16.), &[style]);
721        assert_eq!(layout.len, line.len());
722        assert!(layout.runs.is_empty());
723
724        let line = "a\u{feff}b";
725        style.len = line.len();
726        let layout = fonts.layout_line(line, px(16.), &[style]);
727        assert_eq!(layout.len, line.len());
728        assert_eq!(layout.runs.len(), 1);
729        assert_eq!(layout.runs[0].glyphs.len(), 2);
730        assert_eq!(layout.runs[0].glyphs[0].id, GlyphId(68u32)); // a
731                                                                 // There's no glyph for \u{feff}
732        assert_eq!(layout.runs[0].glyphs[1].id, GlyphId(69u32)); // b
733    }
734}