diff options
Diffstat (limited to 'src/library/text/par.rs')
| -rw-r--r-- | src/library/text/par.rs | 76 |
1 files changed, 65 insertions, 11 deletions
diff --git a/src/library/text/par.rs b/src/library/text/par.rs index 812231c2..70cac1be 100644 --- a/src/library/text/par.rs +++ b/src/library/text/par.rs @@ -27,12 +27,17 @@ pub enum ParChild { #[class] impl ParNode { + /// An ISO 639-1 language code. + pub const LANG: Option<EcoString> = None; /// The direction for text and inline objects. pub const DIR: Dir = Dir::LTR; /// How to align text and inline objects in their line. pub const ALIGN: Align = Align::Left; /// Whether to justify text in its line. pub const JUSTIFY: bool = false; + /// Whether to hyphenate text to improve line breaking. When `auto`, words + /// will will be hyphenated if and only if justification is enabled. + pub const HYPHENATE: Smart<bool> = Smart::Auto; /// The spacing between lines (dependent on scaled font size). pub const LEADING: Linear = Relative::new(0.65).into(); /// The extra spacing between paragraphs (dependent on scaled font size). @@ -49,13 +54,14 @@ impl ParNode { } fn set(args: &mut Args, styles: &mut StyleMap) -> TypResult<()> { + let lang = args.named::<Option<EcoString>>("lang")?; + let mut dir = - args.named("lang")? - .map(|iso: EcoString| match iso.to_lowercase().as_str() { - "ar" | "he" | "fa" | "ur" | "ps" | "yi" => Dir::RTL, - "en" | "fr" | "de" => Dir::LTR, - _ => Dir::LTR, - }); + lang.clone().flatten().map(|iso| match iso.to_lowercase().as_str() { + "ar" | "dv" | "fa" | "he" | "ks" | "pa" | "ps" | "sd" | "ug" | "ur" + | "yi" => Dir::RTL, + _ => Dir::LTR, + }); if let Some(Spanned { v, span }) = args.named::<Spanned<Dir>>("dir")? { if v.axis() != SpecAxis::Horizontal { @@ -74,9 +80,11 @@ impl ParNode { dir.map(|dir| dir.start().into()) }; + styles.set_opt(Self::LANG, lang); styles.set_opt(Self::DIR, dir); styles.set_opt(Self::ALIGN, align); styles.set_opt(Self::JUSTIFY, args.named("justify")?); + styles.set_opt(Self::HYPHENATE, args.named("hyphenate")?); styles.set_opt(Self::LEADING, args.named("leading")?); styles.set_opt(Self::SPACING, args.named("spacing")?); styles.set_opt(Self::INDENT, args.named("indent")?); @@ -137,7 +145,7 @@ impl Layout for ParNode { let par = ParLayout::new(ctx, self, bidi, regions, &styles)?; // Break the paragraph into lines. - let lines = break_into_lines(&mut ctx.fonts, &par, regions.first.x); + let lines = break_into_lines(&mut ctx.fonts, &par, regions.first.x, styles); // Stack the lines into one frame per region. Ok(stack_lines(&ctx.fonts, lines, regions, styles)) @@ -278,6 +286,7 @@ impl<'a> ParLayout<'a> { fonts: &mut FontStore, mut range: Range, mandatory: bool, + hyphen: bool, ) -> LineLayout<'a> { // Find the items which bound the text range. let last_idx = self.find(range.end.saturating_sub(1)).unwrap(); @@ -308,7 +317,10 @@ impl<'a> ParLayout<'a> { // empty string. if !shifted.is_empty() || rest.is_empty() { // Reshape that part. - let reshaped = shaped.reshape(fonts, shifted); + let mut reshaped = shaped.reshape(fonts, shifted); + if hyphen { + reshaped.push_hyphen(fonts); + } last = Some(ParItem::Text(reshaped)); } @@ -524,6 +536,7 @@ fn break_into_lines<'a>( fonts: &mut FontStore, par: &'a ParLayout<'a>, width: Length, + styles: StyleChain, ) -> Vec<LineLayout<'a>> { // The already determined lines and the current line attempt. let mut lines = vec![]; @@ -531,9 +544,9 @@ fn break_into_lines<'a>( let mut last = None; // Find suitable line breaks. - for (end, mandatory) in LineBreakIterator::new(&par.bidi.text) { + for (end, mandatory, hyphen) in breakpoints(&par.bidi.text, styles) { // Compute the line and its size. - let mut line = par.line(fonts, start .. end, mandatory); + let mut line = par.line(fonts, start .. end, mandatory, hyphen); // If the line doesn't fit anymore, we push the last fitting attempt // into the stack and rebuild the line from its end. The resulting @@ -542,7 +555,7 @@ fn break_into_lines<'a>( if let Some((last_line, last_end)) = last.take() { lines.push(last_line); start = last_end; - line = par.line(fonts, start .. end, mandatory); + line = par.line(fonts, start .. end, mandatory, hyphen); } } @@ -565,6 +578,47 @@ fn break_into_lines<'a>( lines } +/// Determine all possible points in the text where lines can broken. +fn breakpoints<'a>( + text: &'a str, + styles: StyleChain, +) -> impl Iterator<Item = (usize, bool, bool)> + 'a { + let mut lang = None; + if styles.get(ParNode::HYPHENATE).unwrap_or(styles.get(ParNode::JUSTIFY)) { + lang = styles + .get_ref(ParNode::LANG) + .as_ref() + .and_then(|iso| iso.as_bytes().try_into().ok()) + .and_then(hypher::Lang::from_iso); + } + + let breaks = LineBreakIterator::new(text); + let mut last = 0; + + if let Some(lang) = lang { + Either::Left(breaks.flat_map(move |(end, mandatory)| { + let word = &text[last .. end]; + let trimmed = word.trim_end_matches(|c: char| !c.is_alphabetic()); + let suffix = last + trimmed.len(); + let mut start = std::mem::replace(&mut last, end); + if trimmed.is_empty() { + Either::Left([(end, mandatory, false)].into_iter()) + } else { + Either::Right(hypher::hyphenate(trimmed, lang).map(move |syllable| { + start += syllable.len(); + if start == suffix { + start = end; + } + let hyphen = start < end; + (start, mandatory && !hyphen, hyphen) + })) + } + })) + } else { + Either::Right(breaks.map(|(e, m)| (e, m, false))) + } +} + /// Combine the lines into one frame per region. fn stack_lines( fonts: &FontStore, |