mirror of
https://github.com/mozilla/gecko-dev.git
synced 2024-10-28 12:45:27 +00:00
c17165f0d9
Source-Repo: https://github.com/servo/servo Source-Revision: 6490d1e1c59c6de3d7ef030c209ad33e22bc6b26
268 lines
8.9 KiB
Rust
268 lines
8.9 KiB
Rust
/* This Source Code Form is subject to the terms of the Mozilla Public
|
|
* License, v. 2.0. If a copy of the MPL was not distributed with this
|
|
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
|
|
|
|
use app_units::Au;
|
|
use euclid::{Point2D, Rect, Size2D};
|
|
use font_template::FontTemplateDescriptor;
|
|
use platform::font::{FontHandle, FontTable};
|
|
use platform::font_context::FontContextHandle;
|
|
use platform::font_template::FontTemplateData;
|
|
use smallvec::SmallVec;
|
|
use std::borrow::ToOwned;
|
|
use std::cell::RefCell;
|
|
use std::rc::Rc;
|
|
use std::str;
|
|
use std::sync::Arc;
|
|
use std::sync::atomic::{ATOMIC_USIZE_INIT, AtomicUsize, Ordering};
|
|
use style::computed_values::{font_stretch, font_variant, font_weight};
|
|
use style::properties::style_structs::Font as FontStyle;
|
|
use text::Shaper;
|
|
use text::glyph::{GlyphId, GlyphStore};
|
|
use text::shaping::ShaperMethods;
|
|
use time;
|
|
use unicode_script::Script;
|
|
use util::cache::HashCache;
|
|
|
|
static TEXT_SHAPING_PERFORMANCE_COUNTER: AtomicUsize = ATOMIC_USIZE_INIT;
|
|
|
|
// FontHandle encapsulates access to the platform's font API,
|
|
// e.g. quartz, FreeType. It provides access to metrics and tables
|
|
// needed by the text shaper as well as access to the underlying font
|
|
// resources needed by the graphics layer to draw glyphs.
|
|
|
|
pub trait FontHandleMethods: Sized {
|
|
fn new_from_template(fctx: &FontContextHandle, template: Arc<FontTemplateData>, pt_size: Option<Au>)
|
|
-> Result<Self, ()>;
|
|
fn template(&self) -> Arc<FontTemplateData>;
|
|
fn family_name(&self) -> String;
|
|
fn face_name(&self) -> String;
|
|
fn is_italic(&self) -> bool;
|
|
fn boldness(&self) -> font_weight::T;
|
|
fn stretchiness(&self) -> font_stretch::T;
|
|
|
|
fn glyph_index(&self, codepoint: char) -> Option<GlyphId>;
|
|
fn glyph_h_advance(&self, GlyphId) -> Option<FractionalPixel>;
|
|
fn glyph_h_kerning(&self, GlyphId, GlyphId) -> FractionalPixel;
|
|
fn metrics(&self) -> FontMetrics;
|
|
fn table_for_tag(&self, FontTableTag) -> Option<Box<FontTable>>;
|
|
}
|
|
|
|
// Used to abstract over the shaper's choice of fixed int representation.
|
|
pub type FractionalPixel = f64;
|
|
|
|
pub type FontTableTag = u32;
|
|
|
|
pub trait FontTableTagConversions {
|
|
fn tag_to_str(&self) -> String;
|
|
}
|
|
|
|
impl FontTableTagConversions for FontTableTag {
|
|
fn tag_to_str(&self) -> String {
|
|
let bytes = [(self >> 24) as u8,
|
|
(self >> 16) as u8,
|
|
(self >> 8) as u8,
|
|
(self >> 0) as u8];
|
|
str::from_utf8(&bytes).unwrap().to_owned()
|
|
}
|
|
}
|
|
|
|
pub trait FontTableMethods {
|
|
fn with_buffer<F>(&self, F) where F: FnOnce(*const u8, usize);
|
|
}
|
|
|
|
#[derive(Clone, Debug, Deserialize, Serialize)]
|
|
pub struct FontMetrics {
|
|
pub underline_size: Au,
|
|
pub underline_offset: Au,
|
|
pub strikeout_size: Au,
|
|
pub strikeout_offset: Au,
|
|
pub leading: Au,
|
|
pub x_height: Au,
|
|
pub em_size: Au,
|
|
pub ascent: Au,
|
|
pub descent: Au,
|
|
pub max_advance: Au,
|
|
pub average_advance: Au,
|
|
pub line_gap: Au,
|
|
}
|
|
|
|
pub type SpecifiedFontStyle = FontStyle;
|
|
|
|
#[derive(Debug)]
|
|
pub struct Font {
|
|
pub handle: FontHandle,
|
|
pub metrics: FontMetrics,
|
|
pub variant: font_variant::T,
|
|
pub descriptor: FontTemplateDescriptor,
|
|
pub requested_pt_size: Au,
|
|
pub actual_pt_size: Au,
|
|
pub shaper: Option<Shaper>,
|
|
pub shape_cache: HashCache<ShapeCacheEntry, Arc<GlyphStore>>,
|
|
pub glyph_advance_cache: HashCache<u32, FractionalPixel>,
|
|
}
|
|
|
|
bitflags! {
|
|
flags ShapingFlags: u8 {
|
|
#[doc = "Set if the text is entirely whitespace."]
|
|
const IS_WHITESPACE_SHAPING_FLAG = 0x01,
|
|
#[doc = "Set if we are to ignore ligatures."]
|
|
const IGNORE_LIGATURES_SHAPING_FLAG = 0x02,
|
|
#[doc = "Set if we are to disable kerning."]
|
|
const DISABLE_KERNING_SHAPING_FLAG = 0x04,
|
|
#[doc = "Text direction is right-to-left."]
|
|
const RTL_FLAG = 0x08,
|
|
}
|
|
}
|
|
|
|
/// Various options that control text shaping.
|
|
#[derive(Clone, Eq, PartialEq, Hash, Copy, Debug)]
|
|
pub struct ShapingOptions {
|
|
/// Spacing to add between each letter. Corresponds to the CSS 2.1 `letter-spacing` property.
|
|
/// NB: You will probably want to set the `IGNORE_LIGATURES_SHAPING_FLAG` if this is non-null.
|
|
pub letter_spacing: Option<Au>,
|
|
/// Spacing to add between each word. Corresponds to the CSS 2.1 `word-spacing` property.
|
|
pub word_spacing: Au,
|
|
/// The Unicode script property of the characters in this run.
|
|
pub script: Script,
|
|
/// Various flags.
|
|
pub flags: ShapingFlags,
|
|
}
|
|
|
|
/// An entry in the shape cache.
|
|
#[derive(Clone, Eq, PartialEq, Hash, Debug)]
|
|
pub struct ShapeCacheEntry {
|
|
text: String,
|
|
options: ShapingOptions,
|
|
}
|
|
|
|
impl Font {
|
|
pub fn shape_text(&mut self, text: &str, options: &ShapingOptions) -> Arc<GlyphStore> {
|
|
self.make_shaper(options);
|
|
|
|
//FIXME: find the equivalent of Equiv and the old ShapeCacheEntryRef
|
|
let shaper = &self.shaper;
|
|
let lookup_key = ShapeCacheEntry {
|
|
text: text.to_owned(),
|
|
options: options.clone(),
|
|
};
|
|
if let Some(glyphs) = self.shape_cache.find(&lookup_key) {
|
|
return glyphs.clone();
|
|
}
|
|
|
|
let start_time = time::precise_time_ns();
|
|
|
|
let mut glyphs = GlyphStore::new(text.chars().count(),
|
|
options.flags.contains(IS_WHITESPACE_SHAPING_FLAG),
|
|
options.flags.contains(RTL_FLAG));
|
|
shaper.as_ref().unwrap().shape_text(text, options, &mut glyphs);
|
|
|
|
let glyphs = Arc::new(glyphs);
|
|
self.shape_cache.insert(ShapeCacheEntry {
|
|
text: text.to_owned(),
|
|
options: *options,
|
|
}, glyphs.clone());
|
|
|
|
let end_time = time::precise_time_ns();
|
|
TEXT_SHAPING_PERFORMANCE_COUNTER.fetch_add((end_time - start_time) as usize,
|
|
Ordering::Relaxed);
|
|
|
|
glyphs
|
|
}
|
|
|
|
fn make_shaper<'a>(&'a mut self, options: &ShapingOptions) -> &'a Shaper {
|
|
// fast path: already created a shaper
|
|
if let Some(ref mut shaper) = self.shaper {
|
|
shaper.set_options(options);
|
|
return shaper
|
|
}
|
|
|
|
let shaper = Shaper::new(self, options);
|
|
self.shaper = Some(shaper);
|
|
self.shaper.as_ref().unwrap()
|
|
}
|
|
|
|
pub fn table_for_tag(&self, tag: FontTableTag) -> Option<Box<FontTable>> {
|
|
let result = self.handle.table_for_tag(tag);
|
|
let status = if result.is_some() { "Found" } else { "Didn't find" };
|
|
|
|
debug!("{} font table[{}] with family={}, face={}",
|
|
status, tag.tag_to_str(),
|
|
self.handle.family_name(), self.handle.face_name());
|
|
|
|
result
|
|
}
|
|
|
|
#[inline]
|
|
pub fn glyph_index(&self, codepoint: char) -> Option<GlyphId> {
|
|
let codepoint = match self.variant {
|
|
font_variant::T::small_caps => codepoint.to_uppercase().next().unwrap(), //FIXME: #5938
|
|
font_variant::T::normal => codepoint,
|
|
};
|
|
self.handle.glyph_index(codepoint)
|
|
}
|
|
|
|
pub fn glyph_h_kerning(&mut self, first_glyph: GlyphId, second_glyph: GlyphId)
|
|
-> FractionalPixel {
|
|
self.handle.glyph_h_kerning(first_glyph, second_glyph)
|
|
}
|
|
|
|
pub fn glyph_h_advance(&mut self, glyph: GlyphId) -> FractionalPixel {
|
|
let handle = &self.handle;
|
|
self.glyph_advance_cache.find_or_create(&glyph, |glyph| {
|
|
match handle.glyph_h_advance(*glyph) {
|
|
Some(adv) => adv,
|
|
None => 10f64 as FractionalPixel // FIXME: Need fallback strategy
|
|
}
|
|
})
|
|
}
|
|
}
|
|
|
|
#[derive(Debug)]
|
|
pub struct FontGroup {
|
|
pub fonts: SmallVec<[Rc<RefCell<Font>>; 8]>,
|
|
}
|
|
|
|
impl FontGroup {
|
|
pub fn new(fonts: SmallVec<[Rc<RefCell<Font>>; 8]>) -> FontGroup {
|
|
FontGroup {
|
|
fonts: fonts,
|
|
}
|
|
}
|
|
}
|
|
|
|
pub struct RunMetrics {
|
|
// may be negative due to negative width (i.e., kerning of '.' in 'P.T.')
|
|
pub advance_width: Au,
|
|
pub ascent: Au, // nonzero
|
|
pub descent: Au, // nonzero
|
|
// this bounding box is relative to the left origin baseline.
|
|
// so, bounding_box.position.y = -ascent
|
|
pub bounding_box: Rect<Au>
|
|
}
|
|
|
|
impl RunMetrics {
|
|
pub fn new(advance: Au, ascent: Au, descent: Au) -> RunMetrics {
|
|
let bounds = Rect::new(Point2D::new(Au(0), -ascent),
|
|
Size2D::new(advance, ascent + descent));
|
|
|
|
// TODO(Issue #125): support loose and tight bounding boxes; using the
|
|
// ascent+descent and advance is sometimes too generous and
|
|
// looking at actual glyph extents can yield a tighter box.
|
|
|
|
RunMetrics {
|
|
advance_width: advance,
|
|
bounding_box: bounds,
|
|
ascent: ascent,
|
|
descent: descent,
|
|
}
|
|
}
|
|
}
|
|
|
|
pub fn get_and_reset_text_shaping_performance_counter() -> usize {
|
|
let value = TEXT_SHAPING_PERFORMANCE_COUNTER.load(Ordering::SeqCst);
|
|
TEXT_SHAPING_PERFORMANCE_COUNTER.store(0, Ordering::SeqCst);
|
|
value
|
|
}
|
|
|