diff options
Diffstat (limited to 'library/src/layout/par.rs')
| -rw-r--r-- | library/src/layout/par.rs | 59 |
1 files changed, 48 insertions, 11 deletions
diff --git a/library/src/layout/par.rs b/library/src/layout/par.rs index 8dd81d29..6178c059 100644 --- a/library/src/layout/par.rs +++ b/library/src/layout/par.rs @@ -145,12 +145,12 @@ impl ParNode { let children = par.children(); // Collect all text into one string for BiDi analysis. - let (text, segments) = collect(&children, &styles, consecutive)?; + let (text, segments, spans) = collect(&children, &styles, consecutive)?; // Perform BiDi analysis and then prepare paragraph layout by building a // representation on which we can do line breaking without layouting // each and every line from scratch. - let p = prepare(&mut vt, &children, &text, segments, styles, region)?; + let p = prepare(&mut vt, &children, &text, segments, spans, styles, region)?; // Break the paragraph into lines. let lines = linebreak(&vt, &p, region.x); @@ -264,6 +264,8 @@ struct Preparation<'a> { bidi: BidiInfo<'a>, /// Text runs, spacing and layouted nodes. items: Vec<Item<'a>>, + /// The span mapper. + spans: SpanMapper, /// The styles shared by all children. styles: StyleChain<'a>, /// Whether to hyphenate if it's the same for all children. @@ -388,6 +390,35 @@ impl<'a> Item<'a> { } } +/// Maps byte offsets back to spans. +pub struct SpanMapper(Vec<(usize, Span)>); + +impl SpanMapper { + /// Create a new span mapper. + pub fn new() -> Self { + Self(vec![]) + } + + /// Push a span for a segment with the given length. + pub fn push(&mut self, len: usize, span: Span) { + self.0.push((len, span)); + } + + /// Determine the span at the given byte offset. + /// + /// May return a detached span. + pub fn span_at(&self, offset: usize) -> (Span, u16) { + let mut cursor = 0; + for &(len, span) in &self.0 { + if (cursor..=cursor + len).contains(&offset) { + return (span, u16::try_from(offset - cursor).unwrap_or(0)); + } + cursor += len; + } + (Span::detached(), 0) + } +} + /// A layouted line, consisting of a sequence of layouted paragraph items that /// are mostly borrowed from the preparation phase. This type enables you to /// measure the size of a line in a range before comitting to building the @@ -485,10 +516,11 @@ fn collect<'a>( children: &'a [Content], styles: &'a StyleChain<'a>, consecutive: bool, -) -> SourceResult<(String, Vec<(Segment<'a>, StyleChain<'a>)>)> { +) -> SourceResult<(String, Vec<(Segment<'a>, StyleChain<'a>)>, SpanMapper)> { let mut full = String::new(); let mut quoter = Quoter::new(); let mut segments = vec![]; + let mut spans = SpanMapper::new(); let mut iter = children.iter().peekable(); if consecutive { @@ -578,6 +610,8 @@ fn collect<'a>( quoter.last(last); } + spans.push(segment.len(), child.span()); + if let (Some((Segment::Text(last_len), last_styles)), Segment::Text(len)) = (segments.last_mut(), segment) { @@ -590,7 +624,7 @@ fn collect<'a>( segments.push((segment, styles)); } - Ok((full, segments)) + Ok((full, segments, spans)) } /// Prepare paragraph layout by shaping the whole paragraph and layouting all @@ -600,6 +634,7 @@ fn prepare<'a>( children: &'a [Content], text: &'a str, segments: Vec<(Segment<'a>, StyleChain<'a>)>, + spans: SpanMapper, styles: StyleChain<'a>, region: Size, ) -> SourceResult<Preparation<'a>> { @@ -620,7 +655,7 @@ fn prepare<'a>( let end = cursor + segment.len(); match segment { Segment::Text(_) => { - shape_range(&mut items, vt, &bidi, cursor..end, styles); + shape_range(&mut items, vt, &bidi, cursor..end, &spans, styles); } Segment::Spacing(spacing) => match spacing { Spacing::Rel(v) => { @@ -655,6 +690,7 @@ fn prepare<'a>( Ok(Preparation { bidi, items, + spans, styles, hyphenate: shared_get(styles, children, TextNode::hyphenate_in), lang: shared_get(styles, children, TextNode::lang_in), @@ -670,11 +706,12 @@ fn shape_range<'a>( vt: &Vt, bidi: &BidiInfo<'a>, range: Range, + spans: &SpanMapper, styles: StyleChain<'a>, ) { - let mut process = |text, level: BidiLevel| { + let mut process = |range: Range, level: BidiLevel| { let dir = if level.is_ltr() { Dir::LTR } else { Dir::RTL }; - let shaped = shape(vt, text, styles, dir); + let shaped = shape(vt, range.start, &bidi.text[range], spans, styles, dir); items.push(Item::Text(shaped)); }; @@ -694,7 +731,7 @@ fn shape_range<'a>( if level != prev_level || !is_compatible(script, prev_script) { if cursor < i { - process(&bidi.text[cursor..i], prev_level); + process(cursor..i, prev_level); } cursor = i; prev_level = level; @@ -704,7 +741,7 @@ fn shape_range<'a>( } } - process(&bidi.text[cursor..range.end], prev_level); + process(cursor..range.end, prev_level); } /// Whether this is not a specific script. @@ -1073,7 +1110,7 @@ fn line<'a>( if hyphen || start + shaped.text.len() > range.end { if hyphen || start < range.end || before.is_empty() { let shifted = start - base..range.end - base; - let mut reshaped = shaped.reshape(vt, shifted); + let mut reshaped = shaped.reshape(vt, &p.spans, shifted); if hyphen || shy { reshaped.push_hyphen(vt); } @@ -1096,7 +1133,7 @@ fn line<'a>( if range.start + shaped.text.len() > end { if range.start < end { let shifted = range.start - base..end - base; - let reshaped = shaped.reshape(vt, shifted); + let reshaped = shaped.reshape(vt, &p.spans, shifted); width += reshaped.width; first = Some(Item::Text(reshaped)); } |