mirror of
https://github.com/servo/servo.git
synced 2025-08-05 13:40:08 +01:00
layout: Add support for white-space-collapse: break-spaces
(#32388)
This change adds support for `white-space-collapse: break-spaces` and adds initial parsing support for `overflow-wrap` and `word-break`. The later two properties are not fully supported, only in their interaction with `break-spaces`. This is a preliminary change preparing to implement them. In addition, `break_and_shape` is now forked and added to Layout 2020. This function is going to change a lot soon and forking is preparation for this. More code that is only used by Layout 2013 is moved from `gfx` to that crate. Co-authored-by: Rakhi Sharma <atbrakhi@igalia.com>
This commit is contained in:
parent
c0dedf06d6
commit
60b4b6c9f0
96 changed files with 410 additions and 537 deletions
442
components/layout/text_run.rs
Normal file
442
components/layout/text_run.rs
Normal file
|
@ -0,0 +1,442 @@
|
|||
/* 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 https://mozilla.org/MPL/2.0/. */
|
||||
|
||||
use std::cell::Cell;
|
||||
use std::cmp::max;
|
||||
use std::slice::Iter;
|
||||
use std::sync::Arc;
|
||||
|
||||
use app_units::Au;
|
||||
use gfx::font::{FontMetrics, FontRef, RunMetrics, ShapingFlags, ShapingOptions};
|
||||
use gfx::text::glyph::{ByteIndex, GlyphRun, GlyphStore};
|
||||
use log::debug;
|
||||
use range::Range;
|
||||
use serde::{Deserialize, Serialize};
|
||||
use style::str::char_is_whitespace;
|
||||
use unicode_bidi as bidi;
|
||||
use webrender_api::FontInstanceKey;
|
||||
use xi_unicode::LineBreakLeafIter;
|
||||
|
||||
thread_local! {
|
||||
static INDEX_OF_FIRST_GLYPH_RUN_CACHE: Cell<Option<(*const TextRun, ByteIndex, usize)>> =
|
||||
Cell::new(None)
|
||||
}
|
||||
|
||||
/// A single "paragraph" of text in one font size and style.
|
||||
#[derive(Clone, Debug, Deserialize, Serialize)]
|
||||
pub struct TextRun {
|
||||
/// The UTF-8 string represented by this text run.
|
||||
pub text: Arc<String>,
|
||||
pub pt_size: Au,
|
||||
pub font_metrics: FontMetrics,
|
||||
pub font_key: FontInstanceKey,
|
||||
/// The glyph runs that make up this text run.
|
||||
pub glyphs: Arc<Vec<GlyphRun>>,
|
||||
pub bidi_level: bidi::Level,
|
||||
pub extra_word_spacing: Au,
|
||||
}
|
||||
|
||||
impl Drop for TextRun {
|
||||
fn drop(&mut self) {
|
||||
// Invalidate the glyph run cache if it was our text run that got freed.
|
||||
INDEX_OF_FIRST_GLYPH_RUN_CACHE.with(|index_of_first_glyph_run_cache| {
|
||||
if let Some((text_run_ptr, _, _)) = index_of_first_glyph_run_cache.get() {
|
||||
if text_run_ptr == (self as *const TextRun) {
|
||||
index_of_first_glyph_run_cache.set(None);
|
||||
}
|
||||
}
|
||||
})
|
||||
}
|
||||
}
|
||||
|
||||
pub struct NaturalWordSliceIterator<'a> {
|
||||
glyphs: &'a [GlyphRun],
|
||||
index: usize,
|
||||
range: Range<ByteIndex>,
|
||||
reverse: bool,
|
||||
}
|
||||
|
||||
/// A "slice" of a text run is a series of contiguous glyphs that all belong to the same glyph
|
||||
/// store. Line breaking strategies yield these.
|
||||
pub struct TextRunSlice<'a> {
|
||||
/// The glyph store that the glyphs in this slice belong to.
|
||||
pub glyphs: &'a GlyphStore,
|
||||
/// The byte index that this slice begins at, relative to the start of the *text run*.
|
||||
pub offset: ByteIndex,
|
||||
/// The range that these glyphs encompass, relative to the start of the *glyph store*.
|
||||
pub range: Range<ByteIndex>,
|
||||
}
|
||||
|
||||
impl<'a> TextRunSlice<'a> {
|
||||
/// Returns the range that these glyphs encompass, relative to the start of the *text run*.
|
||||
#[inline]
|
||||
pub fn text_run_range(&self) -> Range<ByteIndex> {
|
||||
let mut range = self.range;
|
||||
range.shift_by(self.offset);
|
||||
range
|
||||
}
|
||||
}
|
||||
|
||||
impl<'a> Iterator for NaturalWordSliceIterator<'a> {
|
||||
type Item = TextRunSlice<'a>;
|
||||
|
||||
// inline(always) due to the inefficient rt failures messing up inline heuristics, I think.
|
||||
#[inline(always)]
|
||||
fn next(&mut self) -> Option<TextRunSlice<'a>> {
|
||||
let slice_glyphs;
|
||||
if self.reverse {
|
||||
if self.index == 0 {
|
||||
return None;
|
||||
}
|
||||
self.index -= 1;
|
||||
slice_glyphs = &self.glyphs[self.index];
|
||||
} else {
|
||||
if self.index >= self.glyphs.len() {
|
||||
return None;
|
||||
}
|
||||
slice_glyphs = &self.glyphs[self.index];
|
||||
self.index += 1;
|
||||
}
|
||||
|
||||
let mut byte_range = self.range.intersect(&slice_glyphs.range);
|
||||
let slice_range_begin = slice_glyphs.range.begin();
|
||||
byte_range.shift_by(-slice_range_begin);
|
||||
|
||||
if !byte_range.is_empty() {
|
||||
Some(TextRunSlice {
|
||||
glyphs: &slice_glyphs.glyph_store,
|
||||
offset: slice_range_begin,
|
||||
range: byte_range,
|
||||
})
|
||||
} else {
|
||||
None
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
pub struct CharacterSliceIterator<'a> {
|
||||
text: &'a str,
|
||||
glyph_run: Option<&'a GlyphRun>,
|
||||
glyph_run_iter: Iter<'a, GlyphRun>,
|
||||
range: Range<ByteIndex>,
|
||||
}
|
||||
|
||||
impl<'a> Iterator for CharacterSliceIterator<'a> {
|
||||
type Item = TextRunSlice<'a>;
|
||||
|
||||
// inline(always) due to the inefficient rt failures messing up inline heuristics, I think.
|
||||
#[inline(always)]
|
||||
fn next(&mut self) -> Option<TextRunSlice<'a>> {
|
||||
let glyph_run = self.glyph_run?;
|
||||
|
||||
debug_assert!(!self.range.is_empty());
|
||||
let byte_start = self.range.begin();
|
||||
let byte_len = match self.text[byte_start.to_usize()..].chars().next() {
|
||||
Some(ch) => ByteIndex(ch.len_utf8() as isize),
|
||||
None => unreachable!(), // XXX refactor?
|
||||
};
|
||||
|
||||
self.range.adjust_by(byte_len, -byte_len);
|
||||
if self.range.is_empty() {
|
||||
// We're done.
|
||||
self.glyph_run = None
|
||||
} else if self.range.intersect(&glyph_run.range).is_empty() {
|
||||
// Move on to the next glyph run.
|
||||
self.glyph_run = self.glyph_run_iter.next();
|
||||
}
|
||||
|
||||
let index_within_glyph_run = byte_start - glyph_run.range.begin();
|
||||
Some(TextRunSlice {
|
||||
glyphs: &glyph_run.glyph_store,
|
||||
offset: glyph_run.range.begin(),
|
||||
range: Range::new(index_within_glyph_run, byte_len),
|
||||
})
|
||||
}
|
||||
}
|
||||
|
||||
impl<'a> TextRun {
|
||||
/// Constructs a new text run. Also returns if there is a line break at the beginning
|
||||
pub fn new(
|
||||
font: FontRef,
|
||||
text: String,
|
||||
options: &ShapingOptions,
|
||||
bidi_level: bidi::Level,
|
||||
breaker: &mut Option<LineBreakLeafIter>,
|
||||
) -> (TextRun, bool) {
|
||||
let (glyphs, break_at_zero) =
|
||||
TextRun::break_and_shape(font.clone(), &text, options, breaker);
|
||||
(
|
||||
TextRun {
|
||||
text: Arc::new(text),
|
||||
font_metrics: font.metrics.clone(),
|
||||
font_key: font.font_key,
|
||||
pt_size: font.descriptor.pt_size,
|
||||
glyphs: Arc::new(glyphs),
|
||||
bidi_level,
|
||||
extra_word_spacing: Au(0),
|
||||
},
|
||||
break_at_zero,
|
||||
)
|
||||
}
|
||||
|
||||
pub fn break_and_shape(
|
||||
font: FontRef,
|
||||
text: &str,
|
||||
options: &ShapingOptions,
|
||||
breaker: &mut Option<LineBreakLeafIter>,
|
||||
) -> (Vec<GlyphRun>, bool) {
|
||||
let mut glyphs = vec![];
|
||||
let mut slice = 0..0;
|
||||
|
||||
let mut finished = false;
|
||||
let mut break_at_zero = false;
|
||||
|
||||
if breaker.is_none() {
|
||||
if text.is_empty() {
|
||||
return (glyphs, true);
|
||||
}
|
||||
*breaker = Some(LineBreakLeafIter::new(text, 0));
|
||||
}
|
||||
|
||||
let breaker = breaker.as_mut().unwrap();
|
||||
|
||||
let mut push_range = |range: &std::ops::Range<usize>, options: &ShapingOptions| {
|
||||
glyphs.push(GlyphRun {
|
||||
glyph_store: font.shape_text(&text[range.clone()], options),
|
||||
range: Range::new(
|
||||
ByteIndex(range.start as isize),
|
||||
ByteIndex(range.len() as isize),
|
||||
),
|
||||
});
|
||||
};
|
||||
|
||||
while !finished {
|
||||
let (idx, _is_hard_break) = breaker.next(text);
|
||||
if idx == text.len() {
|
||||
finished = true;
|
||||
}
|
||||
if idx == 0 {
|
||||
break_at_zero = true;
|
||||
}
|
||||
|
||||
// Extend the slice to the next UAX#14 line break opportunity.
|
||||
slice.end = idx;
|
||||
let word = &text[slice.clone()];
|
||||
|
||||
// Split off any trailing whitespace into a separate glyph run.
|
||||
let mut whitespace = slice.end..slice.end;
|
||||
let mut rev_char_indices = word.char_indices().rev().peekable();
|
||||
let ends_with_newline = rev_char_indices.peek().map_or(false, |&(_, c)| c == '\n');
|
||||
if let Some((i, _)) = rev_char_indices
|
||||
.take_while(|&(_, c)| char_is_whitespace(c))
|
||||
.last()
|
||||
{
|
||||
whitespace.start = slice.start + i;
|
||||
slice.end = whitespace.start;
|
||||
} else if idx != text.len() && options.flags.contains(ShapingFlags::KEEP_ALL_FLAG) {
|
||||
// If there's no whitespace and word-break is set to
|
||||
// keep-all, try increasing the slice.
|
||||
continue;
|
||||
}
|
||||
if !slice.is_empty() {
|
||||
push_range(&slice, options);
|
||||
}
|
||||
if !whitespace.is_empty() {
|
||||
let mut options = *options;
|
||||
options
|
||||
.flags
|
||||
.insert(ShapingFlags::IS_WHITESPACE_SHAPING_FLAG);
|
||||
|
||||
// The breaker breaks after every newline, so either there is none,
|
||||
// or there is exactly one at the very end. In the latter case,
|
||||
// split it into a different run. That's because shaping considers
|
||||
// a newline to have the same advance as a space, but during layout
|
||||
// we want to treat the newline as having no advance.
|
||||
if ends_with_newline {
|
||||
whitespace.end -= 1;
|
||||
if !whitespace.is_empty() {
|
||||
push_range(&whitespace, &options);
|
||||
}
|
||||
whitespace.start = whitespace.end;
|
||||
whitespace.end += 1;
|
||||
}
|
||||
push_range(&whitespace, &options);
|
||||
}
|
||||
slice.start = whitespace.end;
|
||||
}
|
||||
(glyphs, break_at_zero)
|
||||
}
|
||||
|
||||
pub fn ascent(&self) -> Au {
|
||||
self.font_metrics.ascent
|
||||
}
|
||||
|
||||
pub fn advance_for_range(&self, range: &Range<ByteIndex>) -> Au {
|
||||
if range.is_empty() {
|
||||
return Au(0);
|
||||
}
|
||||
|
||||
// TODO(Issue #199): alter advance direction for RTL
|
||||
// TODO(Issue #98): using inter-char and inter-word spacing settings when measuring text
|
||||
self.natural_word_slices_in_range(range)
|
||||
.fold(Au(0), |advance, slice| {
|
||||
advance +
|
||||
slice
|
||||
.glyphs
|
||||
.advance_for_byte_range(&slice.range, self.extra_word_spacing)
|
||||
})
|
||||
}
|
||||
|
||||
pub fn metrics_for_range(&self, range: &Range<ByteIndex>) -> RunMetrics {
|
||||
RunMetrics::new(
|
||||
self.advance_for_range(range),
|
||||
self.font_metrics.ascent,
|
||||
self.font_metrics.descent,
|
||||
)
|
||||
}
|
||||
|
||||
pub fn metrics_for_slice(
|
||||
&self,
|
||||
glyphs: &GlyphStore,
|
||||
slice_range: &Range<ByteIndex>,
|
||||
) -> RunMetrics {
|
||||
RunMetrics::new(
|
||||
glyphs.advance_for_byte_range(slice_range, self.extra_word_spacing),
|
||||
self.font_metrics.ascent,
|
||||
self.font_metrics.descent,
|
||||
)
|
||||
}
|
||||
|
||||
pub fn min_width_for_range(&self, range: &Range<ByteIndex>) -> Au {
|
||||
debug!("iterating outer range {:?}", range);
|
||||
self.natural_word_slices_in_range(range)
|
||||
.fold(Au(0), |max_piece_width, slice| {
|
||||
debug!("iterated on {:?}[{:?}]", slice.offset, slice.range);
|
||||
max(max_piece_width, self.advance_for_range(&slice.range))
|
||||
})
|
||||
}
|
||||
|
||||
pub fn minimum_splittable_inline_size(&self, range: &Range<ByteIndex>) -> Au {
|
||||
match self.natural_word_slices_in_range(range).next() {
|
||||
None => Au(0),
|
||||
Some(slice) => self.advance_for_range(&slice.range),
|
||||
}
|
||||
}
|
||||
|
||||
/// Returns the index of the first glyph run containing the given character index.
|
||||
fn index_of_first_glyph_run_containing(&self, index: ByteIndex) -> Option<usize> {
|
||||
let self_ptr = self as *const TextRun;
|
||||
INDEX_OF_FIRST_GLYPH_RUN_CACHE.with(|index_of_first_glyph_run_cache| {
|
||||
if let Some((last_text_run, last_index, last_result)) =
|
||||
index_of_first_glyph_run_cache.get()
|
||||
{
|
||||
if last_text_run == self_ptr && last_index == index {
|
||||
return Some(last_result);
|
||||
}
|
||||
}
|
||||
|
||||
if let Ok(result) = self
|
||||
.glyphs
|
||||
.binary_search_by(|current| current.compare(&index))
|
||||
{
|
||||
index_of_first_glyph_run_cache.set(Some((self_ptr, index, result)));
|
||||
Some(result)
|
||||
} else {
|
||||
None
|
||||
}
|
||||
})
|
||||
}
|
||||
|
||||
pub fn on_glyph_run_boundary(&self, index: ByteIndex) -> bool {
|
||||
if let Some(glyph_index) = self.index_of_first_glyph_run_containing(index) {
|
||||
self.glyphs[glyph_index].range.begin() == index
|
||||
} else {
|
||||
true
|
||||
}
|
||||
}
|
||||
|
||||
/// Returns the index in the range of the first glyph advancing over given advance
|
||||
pub fn range_index_of_advance(&self, range: &Range<ByteIndex>, advance: Au) -> usize {
|
||||
// TODO(Issue #199): alter advance direction for RTL
|
||||
// TODO(Issue #98): using inter-char and inter-word spacing settings when measuring text
|
||||
let mut remaining = advance;
|
||||
self.natural_word_slices_in_range(range)
|
||||
.map(|slice| {
|
||||
let (slice_index, slice_advance) = slice.glyphs.range_index_of_advance(
|
||||
&slice.range,
|
||||
remaining,
|
||||
self.extra_word_spacing,
|
||||
);
|
||||
remaining -= slice_advance;
|
||||
slice_index
|
||||
})
|
||||
.sum()
|
||||
}
|
||||
|
||||
/// Returns an iterator that will iterate over all slices of glyphs that represent natural
|
||||
/// words in the given range.
|
||||
pub fn natural_word_slices_in_range(
|
||||
&'a self,
|
||||
range: &Range<ByteIndex>,
|
||||
) -> NaturalWordSliceIterator<'a> {
|
||||
let index = match self.index_of_first_glyph_run_containing(range.begin()) {
|
||||
None => self.glyphs.len(),
|
||||
Some(index) => index,
|
||||
};
|
||||
NaturalWordSliceIterator {
|
||||
glyphs: &self.glyphs[..],
|
||||
index,
|
||||
range: *range,
|
||||
reverse: false,
|
||||
}
|
||||
}
|
||||
|
||||
/// Returns an iterator that over natural word slices in visual order (left to right or
|
||||
/// right to left, depending on the bidirectional embedding level).
|
||||
pub fn natural_word_slices_in_visual_order(
|
||||
&'a self,
|
||||
range: &Range<ByteIndex>,
|
||||
) -> NaturalWordSliceIterator<'a> {
|
||||
// Iterate in reverse order if bidi level is RTL.
|
||||
let reverse = self.bidi_level.is_rtl();
|
||||
|
||||
let index = if reverse {
|
||||
match self.index_of_first_glyph_run_containing(range.end() - ByteIndex(1)) {
|
||||
Some(i) => i + 1, // In reverse mode, index points one past the next element.
|
||||
None => 0,
|
||||
}
|
||||
} else {
|
||||
match self.index_of_first_glyph_run_containing(range.begin()) {
|
||||
Some(i) => i,
|
||||
None => self.glyphs.len(),
|
||||
}
|
||||
};
|
||||
NaturalWordSliceIterator {
|
||||
glyphs: &self.glyphs[..],
|
||||
index,
|
||||
range: *range,
|
||||
reverse,
|
||||
}
|
||||
}
|
||||
|
||||
/// Returns an iterator that will iterate over all slices of glyphs that represent individual
|
||||
/// characters in the given range.
|
||||
pub fn character_slices_in_range(
|
||||
&'a self,
|
||||
range: &Range<ByteIndex>,
|
||||
) -> CharacterSliceIterator<'a> {
|
||||
let index = match self.index_of_first_glyph_run_containing(range.begin()) {
|
||||
None => self.glyphs.len(),
|
||||
Some(index) => index,
|
||||
};
|
||||
let mut glyph_run_iter = self.glyphs[index..].iter();
|
||||
let first_glyph_run = glyph_run_iter.next();
|
||||
CharacterSliceIterator {
|
||||
text: &self.text,
|
||||
glyph_run: first_glyph_run,
|
||||
glyph_run_iter,
|
||||
range: *range,
|
||||
}
|
||||
}
|
||||
}
|
Loading…
Add table
Add a link
Reference in a new issue