ZIm/crates/gpui/src/platform/mac/text_system.rs
2024-01-22 19:33:45 -08:00

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use crate::{
point, px, size, Bounds, DevicePixels, Font, FontFeatures, FontId, FontMetrics, FontRun,
FontStyle, FontWeight, GlyphId, LineLayout, Pixels, PlatformTextSystem, Point,
RenderGlyphParams, Result, ShapedGlyph, ShapedRun, SharedString, Size, SUBPIXEL_VARIANTS,
};
use anyhow::anyhow;
use cocoa::appkit::{CGFloat, CGPoint};
use collections::{BTreeSet, HashMap};
use core_foundation::{
array::CFIndex,
attributed_string::{CFAttributedStringRef, CFMutableAttributedString},
base::{CFRange, TCFType},
string::CFString,
};
use core_graphics::{
base::{kCGImageAlphaPremultipliedLast, CGGlyph},
color_space::CGColorSpace,
context::CGContext,
};
use core_text::{font::CTFont, line::CTLine, string_attributes::kCTFontAttributeName};
use font_kit::{
font::Font as FontKitFont,
handle::Handle,
hinting::HintingOptions,
metrics::Metrics,
properties::{Style as FontkitStyle, Weight as FontkitWeight},
source::SystemSource,
sources::mem::MemSource,
};
use parking_lot::{RwLock, RwLockUpgradableReadGuard};
use pathfinder_geometry::{
rect::{RectF, RectI},
transform2d::Transform2F,
vector::{Vector2F, Vector2I},
};
use smallvec::SmallVec;
use std::{char, cmp, convert::TryFrom, ffi::c_void, sync::Arc};
use super::open_type;
#[allow(non_upper_case_globals)]
const kCGImageAlphaOnly: u32 = 7;
pub(crate) struct MacTextSystem(RwLock<MacTextSystemState>);
struct MacTextSystemState {
memory_source: MemSource,
system_source: SystemSource,
fonts: Vec<FontKitFont>,
font_selections: HashMap<Font, FontId>,
font_ids_by_postscript_name: HashMap<String, FontId>,
font_ids_by_family_name: HashMap<SharedString, SmallVec<[FontId; 4]>>,
postscript_names_by_font_id: HashMap<FontId, String>,
}
impl MacTextSystem {
pub(crate) fn new() -> Self {
Self(RwLock::new(MacTextSystemState {
memory_source: MemSource::empty(),
system_source: SystemSource::new(),
fonts: Vec::new(),
font_selections: HashMap::default(),
font_ids_by_postscript_name: HashMap::default(),
font_ids_by_family_name: HashMap::default(),
postscript_names_by_font_id: HashMap::default(),
}))
}
}
impl Default for MacTextSystem {
fn default() -> Self {
Self::new()
}
}
impl PlatformTextSystem for MacTextSystem {
fn add_fonts(&self, fonts: &[Arc<Vec<u8>>]) -> Result<()> {
self.0.write().add_fonts(fonts)
}
fn all_font_names(&self) -> Vec<String> {
let collection = core_text::font_collection::create_for_all_families();
let Some(descriptors) = collection.get_descriptors() else {
return Vec::new();
};
let mut names = BTreeSet::new();
for descriptor in descriptors.into_iter() {
names.extend(lenient_font_attributes::family_name(&descriptor));
}
if let Ok(fonts_in_memory) = self.0.read().memory_source.all_families() {
names.extend(fonts_in_memory);
}
names.into_iter().collect()
}
fn all_font_families(&self) -> Vec<String> {
self.0
.read()
.system_source
.all_families()
.expect("core text should never return an error")
}
fn font_id(&self, font: &Font) -> Result<FontId> {
let lock = self.0.upgradable_read();
if let Some(font_id) = lock.font_selections.get(font) {
Ok(*font_id)
} else {
let mut lock = RwLockUpgradableReadGuard::upgrade(lock);
let candidates = if let Some(font_ids) = lock.font_ids_by_family_name.get(&font.family)
{
font_ids.as_slice()
} else {
let font_ids = lock.load_family(&font.family, font.features)?;
lock.font_ids_by_family_name
.insert(font.family.clone(), font_ids);
lock.font_ids_by_family_name[&font.family].as_ref()
};
let candidate_properties = candidates
.iter()
.map(|font_id| lock.fonts[font_id.0].properties())
.collect::<SmallVec<[_; 4]>>();
let ix = font_kit::matching::find_best_match(
&candidate_properties,
&font_kit::properties::Properties {
style: font.style.into(),
weight: font.weight.into(),
stretch: Default::default(),
},
)?;
let font_id = candidates[ix];
lock.font_selections.insert(font.clone(), font_id);
Ok(font_id)
}
}
fn font_metrics(&self, font_id: FontId) -> FontMetrics {
self.0.read().fonts[font_id.0].metrics().into()
}
fn typographic_bounds(&self, font_id: FontId, glyph_id: GlyphId) -> Result<Bounds<f32>> {
Ok(self.0.read().fonts[font_id.0]
.typographic_bounds(glyph_id.0)?
.into())
}
fn advance(&self, font_id: FontId, glyph_id: GlyphId) -> Result<Size<f32>> {
self.0.read().advance(font_id, glyph_id)
}
fn glyph_for_char(&self, font_id: FontId, ch: char) -> Option<GlyphId> {
self.0.read().glyph_for_char(font_id, ch)
}
fn glyph_raster_bounds(&self, params: &RenderGlyphParams) -> Result<Bounds<DevicePixels>> {
self.0.read().raster_bounds(params)
}
fn rasterize_glyph(
&self,
glyph_id: &RenderGlyphParams,
raster_bounds: Bounds<DevicePixels>,
) -> Result<(Size<DevicePixels>, Vec<u8>)> {
self.0.read().rasterize_glyph(glyph_id, raster_bounds)
}
fn layout_line(&self, text: &str, font_size: Pixels, font_runs: &[FontRun]) -> LineLayout {
self.0.write().layout_line(text, font_size, font_runs)
}
fn wrap_line(
&self,
text: &str,
font_id: FontId,
font_size: Pixels,
width: Pixels,
) -> Vec<usize> {
self.0.read().wrap_line(text, font_id, font_size, width)
}
}
impl MacTextSystemState {
fn add_fonts(&mut self, fonts: &[Arc<Vec<u8>>]) -> Result<()> {
self.memory_source.add_fonts(
fonts
.iter()
.map(|bytes| Handle::from_memory(bytes.clone(), 0)),
)?;
Ok(())
}
fn load_family(
&mut self,
name: &SharedString,
features: FontFeatures,
) -> Result<SmallVec<[FontId; 4]>> {
let mut font_ids = SmallVec::new();
let family = self
.memory_source
.select_family_by_name(name.as_ref())
.or_else(|_| self.system_source.select_family_by_name(name.as_ref()))?;
for font in family.fonts() {
let mut font = font.load()?;
open_type::apply_features(&mut font, features);
let Some(_) = font.glyph_for_char('m') else {
continue;
};
let font_id = FontId(self.fonts.len());
font_ids.push(font_id);
let postscript_name = font.postscript_name().unwrap();
self.font_ids_by_postscript_name
.insert(postscript_name.clone(), font_id);
self.postscript_names_by_font_id
.insert(font_id, postscript_name);
self.fonts.push(font);
}
Ok(font_ids)
}
fn advance(&self, font_id: FontId, glyph_id: GlyphId) -> Result<Size<f32>> {
Ok(self.fonts[font_id.0].advance(glyph_id.0)?.into())
}
fn glyph_for_char(&self, font_id: FontId, ch: char) -> Option<GlyphId> {
self.fonts[font_id.0].glyph_for_char(ch).map(GlyphId)
}
fn id_for_native_font(&mut self, requested_font: CTFont) -> FontId {
let postscript_name = requested_font.postscript_name();
if let Some(font_id) = self.font_ids_by_postscript_name.get(&postscript_name) {
*font_id
} else {
let font_id = FontId(self.fonts.len());
self.font_ids_by_postscript_name
.insert(postscript_name.clone(), font_id);
self.postscript_names_by_font_id
.insert(font_id, postscript_name);
self.fonts
.push(font_kit::font::Font::from_core_graphics_font(
requested_font.copy_to_CGFont(),
));
font_id
}
}
fn is_emoji(&self, font_id: FontId) -> bool {
self.postscript_names_by_font_id
.get(&font_id)
.map_or(false, |postscript_name| {
postscript_name == "AppleColorEmoji"
})
}
fn raster_bounds(&self, params: &RenderGlyphParams) -> Result<Bounds<DevicePixels>> {
let font = &self.fonts[params.font_id.0];
let scale = Transform2F::from_scale(params.scale_factor);
Ok(font
.raster_bounds(
params.glyph_id.0,
params.font_size.into(),
scale,
HintingOptions::None,
font_kit::canvas::RasterizationOptions::GrayscaleAa,
)?
.into())
}
fn rasterize_glyph(
&self,
params: &RenderGlyphParams,
glyph_bounds: Bounds<DevicePixels>,
) -> Result<(Size<DevicePixels>, Vec<u8>)> {
if glyph_bounds.size.width.0 == 0 || glyph_bounds.size.height.0 == 0 {
Err(anyhow!("glyph bounds are empty"))
} else {
// Add an extra pixel when the subpixel variant isn't zero to make room for anti-aliasing.
let mut bitmap_size = glyph_bounds.size;
if params.subpixel_variant.x > 0 {
bitmap_size.width += DevicePixels(1);
}
if params.subpixel_variant.y > 0 {
bitmap_size.height += DevicePixels(1);
}
let bitmap_size = bitmap_size;
let mut bytes;
let cx;
if params.is_emoji {
bytes = vec![0; bitmap_size.width.0 as usize * 4 * bitmap_size.height.0 as usize];
cx = CGContext::create_bitmap_context(
Some(bytes.as_mut_ptr() as *mut _),
bitmap_size.width.0 as usize,
bitmap_size.height.0 as usize,
8,
bitmap_size.width.0 as usize * 4,
&CGColorSpace::create_device_rgb(),
kCGImageAlphaPremultipliedLast,
);
} else {
bytes = vec![0; bitmap_size.width.0 as usize * bitmap_size.height.0 as usize];
cx = CGContext::create_bitmap_context(
Some(bytes.as_mut_ptr() as *mut _),
bitmap_size.width.0 as usize,
bitmap_size.height.0 as usize,
8,
bitmap_size.width.0 as usize,
&CGColorSpace::create_device_gray(),
kCGImageAlphaOnly,
);
}
// Move the origin to bottom left and account for scaling, this
// makes drawing text consistent with the font-kit's raster_bounds.
cx.translate(
-glyph_bounds.origin.x.0 as CGFloat,
(glyph_bounds.origin.y.0 + glyph_bounds.size.height.0) as CGFloat,
);
cx.scale(
params.scale_factor as CGFloat,
params.scale_factor as CGFloat,
);
let subpixel_shift = params
.subpixel_variant
.map(|v| v as f32 / SUBPIXEL_VARIANTS as f32);
cx.set_allows_font_subpixel_positioning(true);
cx.set_should_subpixel_position_fonts(true);
cx.set_allows_font_subpixel_quantization(false);
cx.set_should_subpixel_quantize_fonts(false);
self.fonts[params.font_id.0]
.native_font()
.clone_with_font_size(f32::from(params.font_size) as CGFloat)
.draw_glyphs(
&[params.glyph_id.0 as CGGlyph],
&[CGPoint::new(
(subpixel_shift.x / params.scale_factor) as CGFloat,
(subpixel_shift.y / params.scale_factor) as CGFloat,
)],
cx,
);
if params.is_emoji {
// Convert from RGBA with premultiplied alpha to BGRA with straight alpha.
for pixel in bytes.chunks_exact_mut(4) {
pixel.swap(0, 2);
let a = pixel[3] as f32 / 255.;
pixel[0] = (pixel[0] as f32 / a) as u8;
pixel[1] = (pixel[1] as f32 / a) as u8;
pixel[2] = (pixel[2] as f32 / a) as u8;
}
}
Ok((bitmap_size, bytes))
}
}
fn layout_line(&mut self, text: &str, font_size: Pixels, font_runs: &[FontRun]) -> LineLayout {
// Construct the attributed string, converting UTF8 ranges to UTF16 ranges.
let mut string = CFMutableAttributedString::new();
{
string.replace_str(&CFString::new(text), CFRange::init(0, 0));
let utf16_line_len = string.char_len() as usize;
let mut ix_converter = StringIndexConverter::new(text);
for run in font_runs {
let utf8_end = ix_converter.utf8_ix + run.len;
let utf16_start = ix_converter.utf16_ix;
if utf16_start >= utf16_line_len {
break;
}
ix_converter.advance_to_utf8_ix(utf8_end);
let utf16_end = cmp::min(ix_converter.utf16_ix, utf16_line_len);
let cf_range =
CFRange::init(utf16_start as isize, (utf16_end - utf16_start) as isize);
let font: &FontKitFont = &self.fonts[run.font_id.0];
unsafe {
string.set_attribute(
cf_range,
kCTFontAttributeName,
&font.native_font().clone_with_font_size(font_size.into()),
);
}
if utf16_end == utf16_line_len {
break;
}
}
}
// Retrieve the glyphs from the shaped line, converting UTF16 offsets to UTF8 offsets.
let line = CTLine::new_with_attributed_string(string.as_concrete_TypeRef());
let mut runs = Vec::new();
for run in line.glyph_runs().into_iter() {
let attributes = run.attributes().unwrap();
let font = unsafe {
attributes
.get(kCTFontAttributeName)
.downcast::<CTFont>()
.unwrap()
};
let font_id = self.id_for_native_font(font);
let mut ix_converter = StringIndexConverter::new(text);
let mut glyphs = SmallVec::new();
for ((glyph_id, position), glyph_utf16_ix) in run
.glyphs()
.iter()
.zip(run.positions().iter())
.zip(run.string_indices().iter())
{
let glyph_utf16_ix = usize::try_from(*glyph_utf16_ix).unwrap();
ix_converter.advance_to_utf16_ix(glyph_utf16_ix);
glyphs.push(ShapedGlyph {
id: GlyphId(*glyph_id as u32),
position: point(position.x as f32, position.y as f32).map(px),
index: ix_converter.utf8_ix,
is_emoji: self.is_emoji(font_id),
});
}
runs.push(ShapedRun { font_id, glyphs })
}
let typographic_bounds = line.get_typographic_bounds();
LineLayout {
runs,
font_size,
width: typographic_bounds.width.into(),
ascent: typographic_bounds.ascent.into(),
descent: typographic_bounds.descent.into(),
len: text.len(),
}
}
fn wrap_line(
&self,
text: &str,
font_id: FontId,
font_size: Pixels,
width: Pixels,
) -> Vec<usize> {
let mut string = CFMutableAttributedString::new();
string.replace_str(&CFString::new(text), CFRange::init(0, 0));
let cf_range = CFRange::init(0, text.encode_utf16().count() as isize);
let font = &self.fonts[font_id.0];
unsafe {
string.set_attribute(
cf_range,
kCTFontAttributeName,
&font.native_font().clone_with_font_size(font_size.into()),
);
let typesetter = CTTypesetterCreateWithAttributedString(string.as_concrete_TypeRef());
let mut ix_converter = StringIndexConverter::new(text);
let mut break_indices = Vec::new();
while ix_converter.utf8_ix < text.len() {
let utf16_len = CTTypesetterSuggestLineBreak(
typesetter,
ix_converter.utf16_ix as isize,
width.into(),
) as usize;
ix_converter.advance_to_utf16_ix(ix_converter.utf16_ix + utf16_len);
if ix_converter.utf8_ix >= text.len() {
break;
}
break_indices.push(ix_converter.utf8_ix);
}
break_indices
}
}
}
#[derive(Clone)]
struct StringIndexConverter<'a> {
text: &'a str,
utf8_ix: usize,
utf16_ix: usize,
}
impl<'a> StringIndexConverter<'a> {
fn new(text: &'a str) -> Self {
Self {
text,
utf8_ix: 0,
utf16_ix: 0,
}
}
fn advance_to_utf8_ix(&mut self, utf8_target: usize) {
for (ix, c) in self.text[self.utf8_ix..].char_indices() {
if self.utf8_ix + ix >= utf8_target {
self.utf8_ix += ix;
return;
}
self.utf16_ix += c.len_utf16();
}
self.utf8_ix = self.text.len();
}
fn advance_to_utf16_ix(&mut self, utf16_target: usize) {
for (ix, c) in self.text[self.utf8_ix..].char_indices() {
if self.utf16_ix >= utf16_target {
self.utf8_ix += ix;
return;
}
self.utf16_ix += c.len_utf16();
}
self.utf8_ix = self.text.len();
}
}
#[repr(C)]
pub(crate) struct __CFTypesetter(c_void);
type CTTypesetterRef = *const __CFTypesetter;
#[link(name = "CoreText", kind = "framework")]
extern "C" {
fn CTTypesetterCreateWithAttributedString(string: CFAttributedStringRef) -> CTTypesetterRef;
fn CTTypesetterSuggestLineBreak(
typesetter: CTTypesetterRef,
start_index: CFIndex,
width: f64,
) -> CFIndex;
}
impl From<Metrics> for FontMetrics {
fn from(metrics: Metrics) -> Self {
FontMetrics {
units_per_em: metrics.units_per_em,
ascent: metrics.ascent,
descent: metrics.descent,
line_gap: metrics.line_gap,
underline_position: metrics.underline_position,
underline_thickness: metrics.underline_thickness,
cap_height: metrics.cap_height,
x_height: metrics.x_height,
bounding_box: metrics.bounding_box.into(),
}
}
}
impl From<RectF> for Bounds<f32> {
fn from(rect: RectF) -> Self {
Bounds {
origin: point(rect.origin_x(), rect.origin_y()),
size: size(rect.width(), rect.height()),
}
}
}
impl From<RectI> for Bounds<DevicePixels> {
fn from(rect: RectI) -> Self {
Bounds {
origin: point(DevicePixels(rect.origin_x()), DevicePixels(rect.origin_y())),
size: size(DevicePixels(rect.width()), DevicePixels(rect.height())),
}
}
}
impl From<Vector2I> for Size<DevicePixels> {
fn from(value: Vector2I) -> Self {
size(value.x().into(), value.y().into())
}
}
impl From<RectI> for Bounds<i32> {
fn from(rect: RectI) -> Self {
Bounds {
origin: point(rect.origin_x(), rect.origin_y()),
size: size(rect.width(), rect.height()),
}
}
}
impl From<Point<u32>> for Vector2I {
fn from(size: Point<u32>) -> Self {
Vector2I::new(size.x as i32, size.y as i32)
}
}
impl From<Vector2F> for Size<f32> {
fn from(vec: Vector2F) -> Self {
size(vec.x(), vec.y())
}
}
impl From<FontWeight> for FontkitWeight {
fn from(value: FontWeight) -> Self {
FontkitWeight(value.0)
}
}
impl From<FontStyle> for FontkitStyle {
fn from(style: FontStyle) -> Self {
match style {
FontStyle::Normal => FontkitStyle::Normal,
FontStyle::Italic => FontkitStyle::Italic,
FontStyle::Oblique => FontkitStyle::Oblique,
}
}
}
// Some fonts may have no attributest despite `core_text` requiring them (and panicking).
// This is the same version as `core_text` has without `expect` calls.
mod lenient_font_attributes {
use core_foundation::{
base::{CFRetain, CFType, TCFType},
string::{CFString, CFStringRef},
};
use core_text::font_descriptor::{
kCTFontFamilyNameAttribute, CTFontDescriptor, CTFontDescriptorCopyAttribute,
};
pub fn family_name(descriptor: &CTFontDescriptor) -> Option<String> {
unsafe { get_string_attribute(descriptor, kCTFontFamilyNameAttribute) }
}
fn get_string_attribute(
descriptor: &CTFontDescriptor,
attribute: CFStringRef,
) -> Option<String> {
unsafe {
let value = CTFontDescriptorCopyAttribute(descriptor.as_concrete_TypeRef(), attribute);
if value.is_null() {
return None;
}
let value = CFType::wrap_under_create_rule(value);
assert!(value.instance_of::<CFString>());
let s = wrap_under_get_rule(value.as_CFTypeRef() as CFStringRef);
Some(s.to_string())
}
}
unsafe fn wrap_under_get_rule(reference: CFStringRef) -> CFString {
assert!(!reference.is_null(), "Attempted to create a NULL object.");
let reference = CFRetain(reference as *const ::std::os::raw::c_void) as CFStringRef;
TCFType::wrap_under_create_rule(reference)
}
}
#[cfg(test)]
mod tests {
use crate::{font, px, FontRun, MacTextSystem, PlatformTextSystem};
#[test]
fn test_wrap_line() {
let fonts = MacTextSystem::new();
let font_id = fonts.font_id(&font("Helvetica")).unwrap();
let line = "one two three four five\n";
let wrap_boundaries = fonts.wrap_line(line, font_id, px(16.), px(64.0));
assert_eq!(wrap_boundaries, &["one two ".len(), "one two three ".len()]);
let line = "aaa ααα ✋✋✋ 🎉🎉🎉\n";
let wrap_boundaries = fonts.wrap_line(line, font_id, px(16.), px(64.0));
assert_eq!(
wrap_boundaries,
&["aaa ααα ".len(), "aaa ααα ✋✋✋ ".len(),]
);
}
#[test]
fn test_layout_line_bom_char() {
let fonts = MacTextSystem::new();
let font_id = fonts.font_id(&font("Helvetica")).unwrap();
let line = "\u{feff}";
let mut style = FontRun {
font_id,
len: line.len(),
};
let layout = fonts.layout_line(line, px(16.), &[style]);
assert_eq!(layout.len, line.len());
assert!(layout.runs.is_empty());
let line = "a\u{feff}b";
style.len = line.len();
let layout = fonts.layout_line(line, px(16.), &[style]);
assert_eq!(layout.len, line.len());
assert_eq!(layout.runs.len(), 1);
assert_eq!(layout.runs[0].glyphs.len(), 2);
assert_eq!(layout.runs[0].glyphs[0].id, 68u32.into()); // a
// There's no glyph for \u{feff}
assert_eq!(layout.runs[0].glyphs[1].id, 69u32.into()); // b
}
}