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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
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@ -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))