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layout: Simplify and improve the correctness of whitespace stripping in

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text layout, and unify the inline layout paths for pre- and
normally-formatted text.

This fixes a lot of "jumpiness" and removes the `new_line_pos` stuff.

Closes #2260.
This commit is contained in:
Patrick Walton 2015-03-30 14:09:37 -07:00
parent 88aa07b7e0
commit 6d61468160
12 changed files with 485 additions and 461 deletions
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78
components/layout/text.rs
View file

@ -6,7 +6,7 @@
#![deny(unsafe_code)]
use fragment::{Fragment, SpecificFragmentInfo, ScannedTextFragmentInfo};
use fragment::{Fragment, SpecificFragmentInfo, ScannedTextFragmentInfo, UnscannedTextFragmentInfo};
use inline::InlineFragments;
use gfx::font::{DISABLE_KERNING_SHAPING_FLAG, FontMetrics, IGNORE_LIGATURES_SHAPING_FLAG};
@ -15,18 +15,19 @@ use gfx::font_context::FontContext;
use gfx::text::glyph::CharIndex;
use gfx::text::text_run::TextRun;
use gfx::text::util::{self, CompressionMode};
use util::linked_list::split_off_head;
use util::geometry::Au;
use util::logical_geometry::{LogicalSize, WritingMode};
use util::range::Range;
use util::smallvec::{SmallVec, SmallVec1};
use std::borrow::ToOwned;
use std::collections::LinkedList;
use std::mem;
use std::sync::Arc;
use style::computed_values::{line_height, text_orientation, text_rendering, text_transform};
use style::computed_values::{white_space};
use style::properties::ComputedValues;
use style::properties::style_structs::Font as FontStyle;
use std::sync::Arc;
use util::geometry::Au;
use util::linked_list::split_off_head;
use util::logical_geometry::{LogicalSize, WritingMode};
use util::range::Range;
use util::smallvec::{SmallVec, SmallVec1};
/// A stack-allocated object for scanning an inline flow into `TextRun`-containing `TextFragment`s.
pub struct TextRunScanner {
@ -40,7 +41,9 @@ impl TextRunScanner {
}
}
pub fn scan_for_runs(&mut self, font_context: &mut FontContext, mut fragments: LinkedList<Fragment>)
pub fn scan_for_runs(&mut self,
font_context: &mut FontContext,
mut fragments: LinkedList<Fragment>)
-> InlineFragments {
debug!("TextRunScanner: scanning {} fragments for text runs...", fragments.len());
@ -50,12 +53,14 @@ impl TextRunScanner {
let mut last_whitespace = true;
while !fragments.is_empty() {
// Create a clump.
split_first_fragment_at_newline_if_necessary(&mut fragments);
self.clump.append(&mut split_off_head(&mut fragments));
while !fragments.is_empty() && self.clump
.back()
.unwrap()
.can_merge_with_fragment(fragments.front()
.unwrap()) {
split_first_fragment_at_newline_if_necessary(&mut fragments);
self.clump.append(&mut split_off_head(&mut fragments));
}
@ -101,7 +106,6 @@ impl TextRunScanner {
//
// Concatenate all of the transformed strings together, saving the new character indices.
let mut new_ranges: SmallVec1<Range<CharIndex>> = SmallVec1::new();
let mut new_line_positions: SmallVec1<NewLinePositions> = SmallVec1::new();
let mut char_total = CharIndex(0);
let run = {
let fontgroup;
@ -137,14 +141,11 @@ impl TextRunScanner {
_ => panic!("Expected an unscanned text fragment!"),
};
let mut new_line_pos = Vec::new();
let old_length = CharIndex(run_text.chars().count() as isize);
last_whitespace = util::transform_text(in_fragment.as_slice(),
compression,
last_whitespace,
&mut run_text,
&mut new_line_pos);
new_line_positions.push(NewLinePositions(new_line_pos));
&mut run_text);
let added_chars = CharIndex(run_text.chars().count() as isize) - old_length;
new_ranges.push(Range::new(char_total, added_chars));
@ -200,13 +201,8 @@ impl TextRunScanner {
}
let text_size = old_fragment.border_box.size;
let &mut NewLinePositions(ref mut new_line_positions) =
new_line_positions.get_mut(logical_offset);
let mut new_text_fragment_info =
box ScannedTextFragmentInfo::new(run.clone(),
range,
mem::replace(new_line_positions, Vec::new()),
text_size);
box ScannedTextFragmentInfo::new(run.clone(), range, text_size);
let new_metrics = new_text_fragment_info.run.metrics_for_range(&range);
let bounding_box_size = bounding_box_for_run_metrics(&new_metrics,
old_fragment.style.writing_mode);
@ -270,8 +266,6 @@ impl TextRunScanner {
}
}
struct NewLinePositions(Vec<CharIndex>);
#[inline]
fn bounding_box_for_run_metrics(metrics: &RunMetrics, writing_mode: WritingMode)
-> LogicalSize<Au> {
@ -318,3 +312,45 @@ pub fn line_height_from_style(style: &ComputedValues, metrics: &FontMetrics) ->
line_height::T::Length(l) => l
}
}
fn split_first_fragment_at_newline_if_necessary(fragments: &mut LinkedList<Fragment>) {
if fragments.len() < 1 {
return
}
let new_fragment = {
let mut first_fragment = fragments.front_mut().unwrap();
let string_before;
{
let unscanned_text_fragment_info = match first_fragment.specific {
SpecificFragmentInfo::UnscannedText(ref mut unscanned_text_fragment_info) => {
unscanned_text_fragment_info
}
_ => return,
};
if first_fragment.style.get_inheritedtext().white_space != white_space::T::pre {
return
}
let position = match unscanned_text_fragment_info.text.find('\n') {
Some(position) if position < unscanned_text_fragment_info.text.len() - 1 => {
position
}
Some(_) | None => return,
};
string_before =
box unscanned_text_fragment_info.text[..(position + 1)].to_owned();
unscanned_text_fragment_info.text =
box unscanned_text_fragment_info.text[(position + 1)..].to_owned();
}
first_fragment.transform(first_fragment.border_box.size,
SpecificFragmentInfo::UnscannedText(UnscannedTextFragmentInfo {
text: string_before,
}))
};
fragments.push_front(new_fragment);
}