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f1fb451791
This is needed in the future to be able to roll back state within the line breaking when we can't fit even a single word into the line and have to go back to fitting glyph by glyph. For the unicode line break iterator the clone is a little more complicated. The iterator is clone, but the type is anonymous. I first had an implementation to moved the iterator into a closure, which was cloned via another control closure. But that's complicated and still involves allocating the various bits & pieces the closure captures. So instead the simpler solution used here is to allocate the breaks into a shared vector.
45 lines
1.3 KiB
Rust
45 lines
1.3 KiB
Rust
// Copyright © SixtyFPS GmbH <info@slint-ui.com>
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// SPDX-License-Identifier: GPL-3.0-only OR LicenseRef-Slint-commercial
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use core::marker::PhantomData;
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pub use unicode_linebreak::BreakOpportunity;
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use crate::SharedVector;
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#[derive(Clone)]
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pub struct LineBreakIterator<'a> {
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breaks: SharedVector<(usize, unicode_linebreak::BreakOpportunity)>,
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pos: usize,
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phantom: PhantomData<&'a str>,
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}
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impl<'a> LineBreakIterator<'a> {
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pub fn new(text: &str) -> Self {
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let iterator = unicode_linebreak::linebreaks(text).filter(|(offset, opportunity)| {
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// unicode-linebreaks emits a mandatory break at the end of the text. We're not interested
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// in that.
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if *offset == text.len() && matches!(opportunity, BreakOpportunity::Mandatory) {
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false
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} else {
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true
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}
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});
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Self { breaks: iterator.collect(), pos: 0, phantom: Default::default() }
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}
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}
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impl<'a> Iterator for LineBreakIterator<'a> {
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type Item = (usize, unicode_linebreak::BreakOpportunity);
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fn next(&mut self) -> Option<Self::Item> {
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if self.pos < self.breaks.len() {
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let i = self.pos;
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self.pos += 1;
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Some(self.breaks[i])
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} else {
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None
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}
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}
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}
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