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remove unnecessary short lived header check

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This commit is contained in:
PgBiel 2025-04-20 13:26:42 -03:00
parent 6e21eae3eb
commit 9a01b9bfe8
1 changed files with 47 additions and 51 deletions
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98
crates/typst-layout/src/grid/layouter.rs
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@ -1462,63 +1462,59 @@ impl<'a> GridLayouter<'a> {
self.current.repeated_header_rows.min(self.lrows.len());
}
let footer_would_be_widow = if let Some(last_header_row) = self
.current
.repeated_header_rows
.checked_sub(1)
.and_then(|last_header_index| self.lrows.get(last_header_index))
{
let last_header_end = last_header_row.index();
if self.grid.rows.len() > last_header_end
&& self
.grid
.footer
.as_ref()
.and_then(Repeatable::as_repeated)
.is_none_or(|footer| footer.start != last_header_end)
&& self.lrows.len() == self.current.repeated_header_rows
&& may_progress_with_offset(
self.regions,
// Since we're trying to find a region where to place all
// repeating + pending headers, it makes sense to use
// 'header_height' and include even non-repeating pending
// headers for this check.
self.current.header_height + self.current.footer_height,
)
{
// Header and footer would be alone in this region, but there are more
// rows beyond the header and the footer. Push an empty region.
self.lrows.clear();
self.current.last_repeated_header_end = 0;
self.current.repeated_header_rows = 0;
true
let footer_would_be_widow =
if !self.lrows.is_empty() && self.current.repeated_header_rows > 0 {
// If headers are repeating, then we already know they are not
// short-lived as that is checked, so they have orphan prevention.
if self.lrows.len() == self.current.repeated_header_rows
&& may_progress_with_offset(
self.regions,
// Since we're trying to find a region where to place all
// repeating + pending headers, it makes sense to use
// 'header_height' and include even non-repeating pending
// headers for this check.
self.current.header_height + self.current.footer_height,
)
{
// Header and footer would be alone in this region, but
// there are more rows beyond the headers and the footer.
// Push an empty region.
self.lrows.clear();
self.current.last_repeated_header_end = 0;
self.current.repeated_header_rows = 0;
true
} else {
false
}
} else if let Some(Repeatable::Repeated(footer)) = &self.grid.footer {
// If no rows other than the footer have been laid out so far,
// and there are rows beside the footer, then don't lay it out
// at all. (Similar check from above, but for the case without
// headers.)
// TODO: widow prevention for non-repeated footers with a
// similar mechanism / when implementing multiple footers.
self.lrows.is_empty()
&& may_progress_with_offset(
self.regions,
// This header height isn't doing much as we just
// confirmed that there are no headers in this region,
// but let's keep it here for correctness. It will add
// zero anyway.
self.current.header_height + self.current.footer_height,
)
&& footer.start != 0
} else {
false
}
} else if let Some(Repeatable::Repeated(footer)) = &self.grid.footer {
// If no rows other than the footer have been laid out so far, and
// there are rows beside the footer, then don't lay it out at all.
// (Similar check from above, but for the case without headers.)
// TODO: widow prevention for non-repeated footers with a similar
// mechanism / when implementing multiple footers.
self.lrows.is_empty()
&& may_progress_with_offset(
self.regions,
// This header height isn't doing much as we just confirmed
// that there are no headers in this region, but let's keep
// it here for correctness. It will add zero anyway.
self.current.header_height + self.current.footer_height,
)
&& footer.start != 0
} else {
false
};
};
let mut laid_out_footer_start = None;
if !footer_would_be_widow {
if let Some(Repeatable::Repeated(footer)) = &self.grid.footer {
// Don't layout the footer if it would be alone with the header in
// the page (hence the widow check), and don't layout it twice.
// Don't layout the footer if it would be alone with the header
// in the page (hence the widow check), and don't layout it
// twice.
// TODO: this check can be replaced by a vector of repeating
// footers in the future.
if self.lrows.iter().all(|row| row.index() < footer.start) {
laid_out_footer_start = Some(footer.start);
self.layout_footer(footer, engine, self.finished.len())?;