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Use byte indices instead of char indices for text runs

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Replace character indices with UTF-8 byte offsets throughout the code dealing
with text shaping and breaking.  This eliminates a lot of complexity when
converting from one to the other, and interoperates better with the rest of
the Rust ecosystem.
This commit is contained in:
Matt Brubeck 2016-04-27 11:22:02 -07:00
parent dba878dfb2
commit 659305fe0a
15 changed files with 259 additions and 437 deletions
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107
components/gfx/text/glyph.rs
View file

@ -164,7 +164,7 @@ impl DetailedGlyph {
#[derive(PartialEq, Clone, Eq, Debug, Copy, Deserialize, Serialize)]
struct DetailedGlyphRecord {
// source string offset/GlyphEntry offset in the TextRun
entry_offset: CharIndex,
entry_offset: ByteIndex,
// offset into the detailed glyphs buffer
detail_offset: usize,
}
@ -205,7 +205,7 @@ impl<'a> DetailedGlyphStore {
}
}
fn add_detailed_glyphs_for_entry(&mut self, entry_offset: CharIndex, glyphs: &[DetailedGlyph]) {
fn add_detailed_glyphs_for_entry(&mut self, entry_offset: ByteIndex, glyphs: &[DetailedGlyph]) {
let entry = DetailedGlyphRecord {
entry_offset: entry_offset,
detail_offset: self.detail_buffer.len(),
@ -229,7 +229,7 @@ impl<'a> DetailedGlyphStore {
self.lookup_is_sorted = false;
}
fn detailed_glyphs_for_entry(&'a self, entry_offset: CharIndex, count: u16)
fn detailed_glyphs_for_entry(&'a self, entry_offset: ByteIndex, count: u16)
-> &'a [DetailedGlyph] {
debug!("Requesting detailed glyphs[n={}] for entry[off={:?}]", count, entry_offset);
@ -256,7 +256,7 @@ impl<'a> DetailedGlyphStore {
}
fn detailed_glyph_with_index(&'a self,
entry_offset: CharIndex,
entry_offset: ByteIndex,
detail_offset: u16)
-> &'a DetailedGlyph {
assert!((detail_offset as usize) <= self.detail_buffer.len());
@ -336,8 +336,8 @@ impl GlyphData {
// values as they are needed from the GlyphStore, using provided offsets.
#[derive(Copy, Clone)]
pub enum GlyphInfo<'a> {
Simple(&'a GlyphStore, CharIndex),
Detail(&'a GlyphStore, CharIndex, u16),
Simple(&'a GlyphStore, ByteIndex),
Detail(&'a GlyphStore, ByteIndex, u16),
}
impl<'a> GlyphInfo<'a> {
@ -413,10 +413,10 @@ pub struct GlyphStore {
int_range_index! {
#[derive(Deserialize, Serialize, RustcEncodable)]
#[doc = "An index that refers to a character in a text run. This could \
#[doc = "An index that refers to a byte offset in a text run. This could \
point to the middle of a glyph."]
#[derive(HeapSizeOf)]
struct CharIndex(isize)
struct ByteIndex(isize)
}
impl<'a> GlyphStore {
@ -436,8 +436,8 @@ impl<'a> GlyphStore {
}
}
pub fn char_len(&self) -> CharIndex {
CharIndex(self.entry_buffer.len() as isize)
pub fn len(&self) -> ByteIndex {
ByteIndex(self.entry_buffer.len() as isize)
}
pub fn is_whitespace(&self) -> bool {
@ -452,7 +452,7 @@ impl<'a> GlyphStore {
#[inline(never)]
fn cache_total_advance(&mut self) {
let mut total_advance = Au(0);
for glyph in self.iter_glyphs_for_char_range(&Range::new(CharIndex(0), self.char_len())) {
for glyph in self.iter_glyphs_for_byte_range(&Range::new(ByteIndex(0), self.len())) {
total_advance = total_advance + glyph.advance()
}
self.total_advance = total_advance
@ -462,10 +462,9 @@ impl<'a> GlyphStore {
self.total_advance
}
/// Adds a single glyph. If `character` is present, this represents a single character;
/// otherwise, this glyph represents multiple characters.
pub fn add_glyph_for_char_index(&mut self,
i: CharIndex,
/// Adds a single glyph.
pub fn add_glyph_for_byte_index(&mut self,
i: ByteIndex,
character: char,
data: &GlyphData) {
let glyph_is_compressible = is_simple_glyph_id(data.id) &&
@ -474,7 +473,7 @@ impl<'a> GlyphStore {
data.cluster_start; // others are stored in detail buffer
debug_assert!(data.ligature_start); // can't compress ligature continuation glyphs.
debug_assert!(i < self.char_len());
debug_assert!(i < self.len());
let mut entry = if glyph_is_compressible {
GlyphEntry::simple(data.id, data.advance)
@ -492,8 +491,8 @@ impl<'a> GlyphStore {
self.entry_buffer[i.to_usize()] = entry;
}
pub fn add_glyphs_for_char_index(&mut self, i: CharIndex, data_for_glyphs: &[GlyphData]) {
assert!(i < self.char_len());
pub fn add_glyphs_for_byte_index(&mut self, i: ByteIndex, data_for_glyphs: &[GlyphData]) {
assert!(i < self.len());
assert!(data_for_glyphs.len() > 0);
let glyph_count = data_for_glyphs.len();
@ -518,48 +517,48 @@ impl<'a> GlyphStore {
}
#[inline]
pub fn iter_glyphs_for_char_range(&'a self, rang: &Range<CharIndex>) -> GlyphIterator<'a> {
if rang.begin() >= self.char_len() {
pub fn iter_glyphs_for_byte_range(&'a self, range: &Range<ByteIndex>) -> GlyphIterator<'a> {
if range.begin() >= self.len() {
panic!("iter_glyphs_for_range: range.begin beyond length!");
}
if rang.end() > self.char_len() {
if range.end() > self.len() {
panic!("iter_glyphs_for_range: range.end beyond length!");
}
GlyphIterator {
store: self,
char_index: if self.is_rtl { rang.end() } else { rang.begin() - CharIndex(1) },
char_range: *rang,
byte_index: if self.is_rtl { range.end() } else { range.begin() - ByteIndex(1) },
byte_range: *range,
glyph_range: None,
}
}
#[inline]
pub fn advance_for_char_range(&self, rang: &Range<CharIndex>) -> Au {
if rang.begin() == CharIndex(0) && rang.end() == self.char_len() {
pub fn advance_for_byte_range(&self, range: &Range<ByteIndex>) -> Au {
if range.begin() == ByteIndex(0) && range.end() == self.len() {
self.total_advance
} else if !self.has_detailed_glyphs {
self.advance_for_char_range_simple_glyphs(rang)
self.advance_for_byte_range_simple_glyphs(range)
} else {
self.advance_for_char_range_slow_path(rang)
self.advance_for_byte_range_slow_path(range)
}
}
#[inline]
pub fn advance_for_char_range_slow_path(&self, rang: &Range<CharIndex>) -> Au {
self.iter_glyphs_for_char_range(rang)
pub fn advance_for_byte_range_slow_path(&self, range: &Range<ByteIndex>) -> Au {
self.iter_glyphs_for_byte_range(range)
.fold(Au(0), |advance, glyph| advance + glyph.advance())
}
#[inline]
#[cfg(any(target_arch = "x86_64", target_arch = "aarch64"))]
fn advance_for_char_range_simple_glyphs(&self, rang: &Range<CharIndex>) -> Au {
fn advance_for_byte_range_simple_glyphs(&self, range: &Range<ByteIndex>) -> Au {
let mask = u32x4::splat(GLYPH_ADVANCE_MASK);
let mut simd_advance = u32x4::splat(0);
let begin = rang.begin().to_usize();
let len = rang.length().to_usize();
let begin = range.begin().to_usize();
let len = range.length().to_usize();
let num_simd_iterations = len / 4;
let leftover_entries = rang.end().to_usize() - (len - num_simd_iterations * 4);
let leftover_entries = range.end().to_usize() - (len - num_simd_iterations * 4);
let buf = self.transmute_entry_buffer_to_u32_buffer();
for i in 0..num_simd_iterations {
@ -575,7 +574,7 @@ impl<'a> GlyphStore {
simd_advance.extract(2) +
simd_advance.extract(3)) as i32;
let mut leftover = Au(0);
for i in leftover_entries..rang.end().to_usize() {
for i in leftover_entries..range.end().to_usize() {
leftover = leftover + self.entry_buffer[i].advance();
}
Au(advance) + leftover
@ -584,8 +583,8 @@ impl<'a> GlyphStore {
/// When SIMD isn't available (non-x86_x64/aarch64), fallback to the slow path.
#[inline]
#[cfg(not(any(target_arch = "x86_64", target_arch = "aarch64")))]
fn advance_for_char_range_simple_glyphs(&self, rang: &Range<CharIndex>) -> Au {
self.advance_for_char_range_slow_path(rang)
fn advance_for_byte_range_simple_glyphs(&self, range: &Range<ByteIndex>) -> Au {
self.advance_for_byte_range_slow_path(range)
}
/// Used for SIMD.
@ -595,12 +594,12 @@ impl<'a> GlyphStore {
unsafe { mem::transmute(self.entry_buffer.as_slice()) }
}
pub fn char_is_space(&self, i: CharIndex) -> bool {
assert!(i < self.char_len());
pub fn char_is_space(&self, i: ByteIndex) -> bool {
assert!(i < self.len());
self.entry_buffer[i.to_usize()].char_is_space()
}
pub fn space_count_in_range(&self, range: &Range<CharIndex>) -> u32 {
pub fn space_count_in_range(&self, range: &Range<ByteIndex>) -> u32 {
let mut spaces = 0;
for index in range.each_index() {
if self.char_is_space(index) {
@ -610,7 +609,7 @@ impl<'a> GlyphStore {
spaces
}
pub fn distribute_extra_space_in_range(&mut self, range: &Range<CharIndex>, space: f64) {
pub fn distribute_extra_space_in_range(&mut self, range: &Range<ByteIndex>, space: f64) {
debug_assert!(space >= 0.0);
if range.is_empty() {
return
@ -659,12 +658,12 @@ impl fmt::Debug for GlyphStore {
}
}
/// An iterator over the glyphs in a character range in a `GlyphStore`.
/// An iterator over the glyphs in a byte range in a `GlyphStore`.
pub struct GlyphIterator<'a> {
store: &'a GlyphStore,
char_index: CharIndex,
char_range: Range<CharIndex>,
glyph_range: Option<EachIndex<isize, CharIndex>>,
byte_index: ByteIndex,
byte_range: Range<ByteIndex>,
glyph_range: Option<EachIndex<isize, ByteIndex>>,
}
impl<'a> GlyphIterator<'a> {
@ -673,7 +672,7 @@ impl<'a> GlyphIterator<'a> {
fn next_glyph_range(&mut self) -> Option<GlyphInfo<'a>> {
match self.glyph_range.as_mut().unwrap().next() {
Some(j) => {
Some(GlyphInfo::Detail(self.store, self.char_index, j.get() as u16 /* ??? */))
Some(GlyphInfo::Detail(self.store, self.byte_index, j.get() as u16 /* ??? */))
}
None => {
// No more glyphs for current character. Try to get another.
@ -685,9 +684,9 @@ impl<'a> GlyphIterator<'a> {
// Slow path when there is a complex glyph.
#[inline(never)]
fn next_complex_glyph(&mut self, entry: &GlyphEntry, i: CharIndex) -> Option<GlyphInfo<'a>> {
fn next_complex_glyph(&mut self, entry: &GlyphEntry, i: ByteIndex) -> Option<GlyphInfo<'a>> {
let glyphs = self.store.detail_store.detailed_glyphs_for_entry(i, entry.glyph_count());
self.glyph_range = Some(range::each_index(CharIndex(0), CharIndex(glyphs.len() as isize)));
self.glyph_range = Some(range::each_index(ByteIndex(0), ByteIndex(glyphs.len() as isize)));
self.next()
}
}
@ -708,17 +707,17 @@ impl<'a> Iterator for GlyphIterator<'a> {
return self.next_glyph_range()
}
// No glyph range. Look at next character.
self.char_index = self.char_index + if self.store.is_rtl {
CharIndex(-1)
// No glyph range. Look at next byte.
self.byte_index = self.byte_index + if self.store.is_rtl {
ByteIndex(-1)
} else {
CharIndex(1)
ByteIndex(1)
};
let i = self.char_index;
if !self.char_range.contains(i) {
let i = self.byte_index;
if !self.byte_range.contains(i) {
return None
}
debug_assert!(i < self.store.char_len());
debug_assert!(i < self.store.len());
let entry = self.store.entry_buffer[i.to_usize()];
if entry.is_simple() {
Some(GlyphInfo::Simple(self.store, i))

149
components/gfx/text/shaping/harfbuzz.rs
View file

@ -35,7 +35,7 @@ use harfbuzz::{hb_position_t, hb_tag_t};
use libc::{c_char, c_int, c_uint, c_void};
use platform::font::FontTable;
use std::{char, cmp, ptr};
use text::glyph::{CharIndex, GlyphData, GlyphId, GlyphStore};
use text::glyph::{ByteIndex, GlyphData, GlyphId, GlyphStore};
use text::shaping::ShaperMethods;
use text::util::{fixed_to_float, float_to_fixed, is_bidi_control};
@ -45,8 +45,7 @@ macro_rules! hb_tag {
);
}
static NO_GLYPH: i32 = -1;
static CONTINUATION_BYTE: i32 = -2;
const NO_GLYPH: i32 = -1;
static KERN: u32 = hb_tag!('k', 'e', 'r', 'n');
static LIGA: u32 = hb_tag!('l', 'i', 'g', 'a');
@ -258,44 +257,18 @@ impl Shaper {
let glyph_data = ShapedGlyphData::new(buffer);
let glyph_count = glyph_data.len();
let byte_max = text.len();
let char_max = text.chars().count();
// GlyphStore records are indexed by character, not byte offset.
// so, we must be careful to increment this when saving glyph entries.
let (mut char_idx, char_step) = if options.flags.contains(RTL_FLAG) {
(CharIndex(char_max as isize - 1), CharIndex(-1))
} else {
(CharIndex(0), CharIndex(1))
};
debug!("Shaped text[char count={}], got back {} glyph info records.",
char_max,
debug!("Shaped text[byte count={}], got back {} glyph info records.",
byte_max,
glyph_count);
if char_max != glyph_count {
debug!("NOTE: Since these are not equal, we probably have been given some complex \
glyphs.");
}
// make map of what chars have glyphs
let mut byte_to_glyph: Vec<i32>;
// fast path: all chars are single-byte.
if byte_max == char_max {
byte_to_glyph = vec![NO_GLYPH; byte_max];
} else {
byte_to_glyph = vec![CONTINUATION_BYTE; byte_max];
for (i, _) in text.char_indices() {
byte_to_glyph[i] = NO_GLYPH;
}
}
let mut byte_to_glyph = vec![NO_GLYPH; byte_max];
debug!("(glyph idx) -> (text byte offset)");
for i in 0..glyph_data.len() {
// loc refers to a *byte* offset within the utf8 string.
let loc = glyph_data.byte_offset_of_glyph(i) as usize;
if loc < byte_max {
assert!(byte_to_glyph[loc] != CONTINUATION_BYTE);
byte_to_glyph[loc] = i as i32;
} else {
debug!("ERROR: tried to set out of range byte_to_glyph: idx={}, glyph idx={}",
@ -312,10 +285,7 @@ impl Shaper {
}
let mut glyph_span = 0..0;
// This span contains first byte of first char, to last byte of last char in range.
// So, char_byte_span.end points to first byte of last+1 char, if it's less than byte_max.
let mut char_byte_span;
let mut byte_range = 0..0;
let mut y_pos = Au(0);
@ -325,106 +295,62 @@ impl Shaper {
while glyph_span.start < glyph_count {
debug!("Processing glyph at idx={}", glyph_span.start);
glyph_span.end = glyph_span.start;
byte_range.end = glyph_data.byte_offset_of_glyph(glyph_span.start) as usize;
let char_byte_start = glyph_data.byte_offset_of_glyph(glyph_span.start) as usize;
char_byte_span = char_byte_start..char_byte_start;
let mut glyph_spans_multiple_characters = false;
// find a range of chars corresponding to this glyph, plus
// any trailing chars that do not have associated glyphs.
while char_byte_span.end < byte_max {
let ch = text[char_byte_span.end..].chars().next().unwrap();
char_byte_span.end += ch.len_utf8();
debug!("Processing char byte span: off={}, len={} for glyph idx={}",
char_byte_span.start, char_byte_span.len(), glyph_span.start);
while char_byte_span.end != byte_max &&
byte_to_glyph[char_byte_span.end] == NO_GLYPH {
debug!("Extending char byte span to include byte offset={} with no associated \
glyph", char_byte_span.end);
let ch = text[char_byte_span.end..].chars().next().unwrap();
char_byte_span.end += ch.len_utf8();
glyph_spans_multiple_characters = true;
while byte_range.end < byte_max {
byte_range.end += 1;
// Extend the byte range to include any following byte without its own glyph.
while byte_range.end < byte_max && byte_to_glyph[byte_range.end] == NO_GLYPH {
byte_range.end += 1;
}
// extend glyph range to max glyph index covered by char_span,
// in cases where one char made several glyphs and left some unassociated chars.
// Extend the glyph range to include all glyphs covered by bytes processed so far.
let mut max_glyph_idx = glyph_span.end;
for i in char_byte_span.clone() {
if byte_to_glyph[i] > NO_GLYPH {
max_glyph_idx = cmp::max(byte_to_glyph[i] as usize + 1, max_glyph_idx);
for glyph_idx in &byte_to_glyph[byte_range.clone()] {
if *glyph_idx != NO_GLYPH {
max_glyph_idx = cmp::max(*glyph_idx as usize + 1, max_glyph_idx);
}
}
if max_glyph_idx > glyph_span.end {
glyph_span.end = max_glyph_idx;
debug!("Extended glyph span (off={}, len={}) to cover char byte span's max \
glyph index",
glyph_span.start, glyph_span.len());
debug!("Extended glyph span to {:?}", glyph_span);
}
// if there's just one glyph, then we don't need further checks.
if glyph_span.len() == 1 { break; }
// if no glyphs were found yet, extend the char byte range more.
if glyph_span.len() == 0 { continue; }
debug!("Complex (multi-glyph to multi-char) association found. This case \
probably doesn't work.");
// If byte_range now includes all the byte offsets found in glyph_span, then we
// have found a contiguous "cluster" and can stop extending it.
let mut all_glyphs_are_within_cluster: bool = true;
for j in glyph_span.clone() {
let loc = glyph_data.byte_offset_of_glyph(j);
if !char_byte_span.contains(loc as usize) {
if !byte_range.contains(loc as usize) {
all_glyphs_are_within_cluster = false;
break
}
}
debug!("All glyphs within char_byte_span cluster?: {}",
all_glyphs_are_within_cluster);
// found a valid range; stop extending char_span.
if all_glyphs_are_within_cluster {
break
}
// Otherwise, the bytes we have seen so far correspond to a non-contiguous set of
// glyphs. Keep extending byte_range until we fill in all the holes in the glyph
// span or reach the end of the text.
}
// character/glyph clump must contain characters.
assert!(char_byte_span.len() > 0);
// character/glyph clump must contain glyphs.
assert!(byte_range.len() > 0);
assert!(glyph_span.len() > 0);
// now char_span is a ligature clump, formed by the glyphs in glyph_span.
// we need to find the chars that correspond to actual glyphs (char_extended_span),
//and set glyph info for those and empty infos for the chars that are continuations.
// Now byte_range is the ligature clump formed by the glyphs in glyph_span.
// We will save these glyphs to the glyph store at the index of the first byte.
let byte_idx = ByteIndex(byte_range.start as isize);
// a simple example:
// chars: 'f' 't' 't'
// glyphs: 'ftt' '' ''
// cgmap: t f f
// gspan: [-]
// cspan: [-]
// covsp: [---------------]
let mut covered_byte_span = char_byte_span.clone();
// extend, clipping at end of text range.
while covered_byte_span.end < byte_max &&
byte_to_glyph[covered_byte_span.end] == NO_GLYPH {
let ch = text[covered_byte_span.end..].chars().next().unwrap();
covered_byte_span.end += ch.len_utf8();
}
if covered_byte_span.start >= byte_max {
// oops, out of range. clip and forget this clump.
glyph_span.start = glyph_span.end;
char_byte_span.start = char_byte_span.end;
}
// fast path: 1-to-1 mapping of single char and single glyph.
if glyph_span.len() == 1 && !glyph_spans_multiple_characters {
if glyph_span.len() == 1 {
// Fast path: 1-to-1 mapping of byte offset to single glyph.
//
// TODO(Issue #214): cluster ranges need to be computed before
// shaping, and then consulted here.
// for now, just pretend that every character is a cluster start.
@ -433,7 +359,7 @@ impl Shaper {
//
// NB: When we acquire the ability to handle ligatures that cross word boundaries,
// we'll need to do something special to handle `word-spacing` properly.
let character = text[char_byte_span.clone()].chars().next().unwrap();
let character = text[byte_range.clone()].chars().next().unwrap();
if is_bidi_control(character) {
// Don't add any glyphs for bidi control chars
} else if character == '\t' {
@ -449,7 +375,7 @@ impl Shaper {
Default::default(),
true,
true);
glyphs.add_glyph_for_char_index(char_idx, character, &data);
glyphs.add_glyph_for_byte_index(byte_idx, character, &data);
} else {
let shape = glyph_data.entry_for_glyph(glyph_span.start, &mut y_pos);
let advance = self.advance_for_shaped_glyph(shape.advance, character, options);
@ -458,7 +384,7 @@ impl Shaper {
shape.offset,
true,
true);
glyphs.add_glyph_for_char_index(char_idx, character, &data);
glyphs.add_glyph_for_byte_index(byte_idx, character, &data);
}
} else {
// collect all glyphs to be assigned to the first character.
@ -473,15 +399,12 @@ impl Shaper {
glyph_i > glyph_span.start));
// all but first are ligature continuations
}
// now add the detailed glyph entry.
glyphs.add_glyphs_for_char_index(char_idx, &datas);
glyphs.add_glyphs_for_byte_index(byte_idx, &datas);
}
// shift up our working spans past things we just handled.
glyph_span.start = glyph_span.end;
char_byte_span.start = char_byte_span.end;
char_idx = char_idx + char_step;
byte_range.start = byte_range.end;
}
// this must be called after adding all glyph data; it sorts the

81
components/gfx/text/text_run.rs
View file

@ -11,11 +11,11 @@ use std::cell::Cell;
use std::cmp::{Ordering, max};
use std::slice::Iter;
use std::sync::Arc;
use text::glyph::{CharIndex, GlyphStore};
use text::glyph::{ByteIndex, GlyphStore};
use webrender_traits;
thread_local! {
static INDEX_OF_FIRST_GLYPH_RUN_CACHE: Cell<Option<(*const TextRun, CharIndex, usize)>> =
static INDEX_OF_FIRST_GLYPH_RUN_CACHE: Cell<Option<(*const TextRun, ByteIndex, usize)>> =
Cell::new(None)
}
@ -51,19 +51,19 @@ impl Drop for TextRun {
pub struct GlyphRun {
/// The glyphs.
pub glyph_store: Arc<GlyphStore>,
/// The range of characters in the containing run.
pub range: Range<CharIndex>,
/// The byte range of characters in the containing run.
pub range: Range<ByteIndex>,
}
pub struct NaturalWordSliceIterator<'a> {
glyphs: &'a [GlyphRun],
index: usize,
range: Range<CharIndex>,
range: Range<ByteIndex>,
reverse: bool,
}
impl GlyphRun {
fn compare(&self, key: &CharIndex) -> Ordering {
fn compare(&self, key: &ByteIndex) -> Ordering {
if *key < self.range.begin() {
Ordering::Greater
} else if *key >= self.range.end() {
@ -79,16 +79,16 @@ impl GlyphRun {
pub struct TextRunSlice<'a> {
/// The glyph store that the glyphs in this slice belong to.
pub glyphs: &'a GlyphStore,
/// The character index that this slice begins at, relative to the start of the *text run*.
pub offset: CharIndex,
/// 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<CharIndex>,
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<CharIndex> {
pub fn text_run_range(&self) -> Range<ByteIndex> {
let mut range = self.range;
range.shift_by(self.offset);
range
@ -116,15 +116,15 @@ impl<'a> Iterator for NaturalWordSliceIterator<'a> {
self.index += 1;
}
let mut char_range = self.range.intersect(&slice_glyphs.range);
let mut byte_range = self.range.intersect(&slice_glyphs.range);
let slice_range_begin = slice_glyphs.range.begin();
char_range.shift_by(-slice_range_begin);
byte_range.shift_by(-slice_range_begin);
if !char_range.is_empty() {
if !byte_range.is_empty() {
Some(TextRunSlice {
glyphs: &*slice_glyphs.glyph_store,
offset: slice_range_begin,
range: char_range,
range: byte_range,
})
} else {
None
@ -133,9 +133,10 @@ impl<'a> Iterator for NaturalWordSliceIterator<'a> {
}
pub struct CharacterSliceIterator<'a> {
text: &'a str,
glyph_run: Option<&'a GlyphRun>,
glyph_run_iter: Iter<'a, GlyphRun>,
range: Range<CharIndex>,
range: Range<ByteIndex>,
}
impl<'a> Iterator for CharacterSliceIterator<'a> {
@ -150,8 +151,13 @@ impl<'a> Iterator for CharacterSliceIterator<'a> {
};
debug_assert!(!self.range.is_empty());
let index_to_return = self.range.begin();
self.range.adjust_by(CharIndex(1), CharIndex(-1));
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
@ -160,11 +166,11 @@ impl<'a> Iterator for CharacterSliceIterator<'a> {
self.glyph_run = self.glyph_run_iter.next();
}
let index_within_glyph_run = index_to_return - glyph_run.range.begin();
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, CharIndex(1)),
range: Range::new(index_within_glyph_run, byte_len),
})
}
}
@ -187,9 +193,9 @@ impl<'a> TextRun {
-> Vec<GlyphRun> {
// TODO(Issue #230): do a better job. See Gecko's LineBreaker.
let mut glyphs = vec!();
let (mut byte_i, mut char_i) = (0, CharIndex(0));
let mut byte_i = 0;
let mut cur_slice_is_whitespace = false;
let (mut byte_last_boundary, mut char_last_boundary) = (0, CharIndex(0));
let mut byte_last_boundary = 0;
for ch in text.chars() {
// Slices alternate between whitespace and non-whitespace,
@ -225,14 +231,13 @@ impl<'a> TextRun {
glyphs.push(GlyphRun {
glyph_store: font.shape_text(slice, &options),
range: Range::new(char_last_boundary, char_i - char_last_boundary),
range: Range::new(ByteIndex(byte_last_boundary as isize),
ByteIndex((byte_i - byte_last_boundary) as isize)),
});
byte_last_boundary = byte_i;
char_last_boundary = char_i;
}
byte_i = byte_i + ch.len_utf8();
char_i = char_i + CharIndex(1);
}
// Create a glyph store for the final slice if it's nonempty.
@ -248,7 +253,8 @@ impl<'a> TextRun {
glyphs.push(GlyphRun {
glyph_store: font.shape_text(slice, &options),
range: Range::new(char_last_boundary, char_i - char_last_boundary),
range: Range::new(ByteIndex(byte_last_boundary as isize),
ByteIndex((byte_i - byte_last_boundary) as isize)),
});
}
@ -263,7 +269,7 @@ impl<'a> TextRun {
self.font_metrics.descent
}
pub fn advance_for_range(&self, range: &Range<CharIndex>) -> Au {
pub fn advance_for_range(&self, range: &Range<ByteIndex>) -> Au {
if range.is_empty() {
return Au(0)
}
@ -272,24 +278,24 @@ impl<'a> TextRun {
// 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_char_range(&slice.range)
advance + slice.glyphs.advance_for_byte_range(&slice.range)
})
}
pub fn metrics_for_range(&self, range: &Range<CharIndex>) -> RunMetrics {
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<CharIndex>)
pub fn metrics_for_slice(&self, glyphs: &GlyphStore, slice_range: &Range<ByteIndex>)
-> RunMetrics {
RunMetrics::new(glyphs.advance_for_char_range(slice_range),
RunMetrics::new(glyphs.advance_for_byte_range(slice_range),
self.font_metrics.ascent,
self.font_metrics.descent)
}
pub fn min_width_for_range(&self, range: &Range<CharIndex>) -> Au {
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);
@ -297,8 +303,8 @@ impl<'a> TextRun {
})
}
/// Returns the index of the first glyph run containing the given character index.
fn index_of_first_glyph_run_containing(&self, index: CharIndex) -> Option<usize> {
/// Returns the index of the first glyph run containing the given byte 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)) =
@ -319,7 +325,7 @@ impl<'a> TextRun {
/// 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<CharIndex>)
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(),
@ -335,13 +341,13 @@ impl<'a> TextRun {
/// 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<CharIndex>)
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 % 2 == 1;
let index = if reverse {
match self.index_of_first_glyph_run_containing(range.end() - CharIndex(1)) {
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
}
@ -361,7 +367,7 @@ impl<'a> TextRun {
/// 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<CharIndex>)
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(),
@ -370,6 +376,7 @@ impl<'a> TextRun {
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: glyph_run_iter,
range: *range,