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#[derive(Debug)]
pub struct BidiRun {
pub start: usize,
pub end: usize,
pub dir: rustybuzz::Direction,
}
#[derive(Debug)]
pub enum BidiAlgo {
Nope(rustybuzz::Direction),
Yep {
default_lev: Option<unicode_bidi::Level>,
},
}
impl BidiAlgo {
pub fn start_dir(&self) -> rustybuzz::Direction {
match self {
BidiAlgo::Nope(dir) => *dir,
BidiAlgo::Yep { default_lev } => {
if let Some(lev) = default_lev {
if lev.is_rtl() {
rustybuzz::Direction::RightToLeft
} else {
rustybuzz::Direction::LeftToRight
}
} else {
rustybuzz::Direction::LeftToRight
}
}
}
}
pub fn visual_runs(&mut self, text: &str, start: usize) -> Vec<BidiRun> {
match self {
BidiAlgo::Nope(dir) => vec![BidiRun {
start,
end: start + text.len(),
dir: *dir,
}],
BidiAlgo::Yep { default_lev } => {
let bidi = unicode_bidi::BidiInfo::new(text, *default_lev);
let mut res_runs = Vec::new();
for para in &bidi.paragraphs {
let line = para.range.clone();
let (levels, runs) = bidi.visual_runs(para, line);
for run in runs {
let lev = levels[run.start];
let dir = if lev.is_rtl() {
rustybuzz::Direction::RightToLeft
} else {
rustybuzz::Direction::LeftToRight
};
if default_lev.is_none() {
// assign for following lines
*default_lev = Some(lev);
}
res_runs.push(BidiRun {
start: start + run.start,
end: start + run.end,
dir,
})
}
}
if res_runs.is_empty() {
let dir = if let Some(lev) = default_lev {
if lev.is_rtl() {
rustybuzz::Direction::RightToLeft
} else {
rustybuzz::Direction::LeftToRight
}
} else {
rustybuzz::Direction::LeftToRight
};
res_runs.push(BidiRun {
start,
end: start + text.len(),
dir,
});
}
res_runs
}
}
}
}