diff options
| -rw-r--r-- | crates/typst/src/layout/flow/collect.rs | 25 | ||||
| -rw-r--r-- | tests/ref/issue-5024-spill-backlog.png | bin | 0 -> 270 bytes | |||
| -rw-r--r-- | tests/suite/layout/flow/flow.typ | 4 |
3 files changed, 23 insertions, 6 deletions
diff --git a/crates/typst/src/layout/flow/collect.rs b/crates/typst/src/layout/flow/collect.rs index 9cd9bdc4..9fc64f06 100644 --- a/crates/typst/src/layout/flow/collect.rs +++ b/crates/typst/src/layout/flow/collect.rs @@ -403,6 +403,7 @@ impl<'a> MultiChild<'a> { full: regions.full, first: regions.size.y, backlog: vec![], + min_backlog_len: regions.backlog.len(), }); } @@ -474,6 +475,7 @@ pub struct MultiSpill<'a, 'b> { first: Abs, full: Abs, backlog: Vec<Abs>, + min_backlog_len: usize, } impl MultiSpill<'_, '_> { @@ -483,17 +485,18 @@ impl MultiSpill<'_, '_> { engine: &mut Engine, regions: Regions, ) -> SourceResult<(Frame, Option<Self>)> { - // We build regions for the whole `MultiChild` with the sizes passed to - // earlier parts of it plus the new regions. Then, we layout the - // complete block, but extract only the suffix that interests us. + // The first region becomes unchangable and committed to our backlog. self.backlog.push(regions.size.y); + // The remaining regions are ephemeral and may be replaced. let mut backlog: Vec<_> = self.backlog.iter().chain(regions.backlog).copied().collect(); - // Remove unnecessary backlog items (also to prevent it from growing - // unnecessarily, which would change the region's hash). - while !backlog.is_empty() && backlog.last().copied() == regions.last { + // Remove unnecessary backlog items to prevent it from growing + // unnecessarily, changing the region's hash. + while backlog.len() > self.min_backlog_len + && backlog.last().copied() == regions.last + { backlog.pop(); } @@ -513,6 +516,16 @@ impl MultiSpill<'_, '_> { .into_iter() .skip(self.backlog.len()); + // Ensure that the backlog never shrinks, so that unwrapping below is at + // least fairly safe. Note that the whole region juggling here is + // fundamentally not ideal: It is a compatibility layer between the old + // (all regions provided upfront) & new (each region provided on-demand, + // like an iterator) layout model. This approach is not 100% correct, as + // in the old model later regions could have an effect on earlier + // frames, but it's the best we can do for now, until the multi + // layouters are refactored to the new model. + self.min_backlog_len = self.min_backlog_len.max(backlog.len()); + // Save the first frame. let frame = frames.next().unwrap(); diff --git a/tests/ref/issue-5024-spill-backlog.png b/tests/ref/issue-5024-spill-backlog.png Binary files differnew file mode 100644 index 00000000..76fd9fbb --- /dev/null +++ b/tests/ref/issue-5024-spill-backlog.png diff --git a/tests/suite/layout/flow/flow.typ b/tests/suite/layout/flow/flow.typ index fcbc005b..5a5e8404 100644 --- a/tests/suite/layout/flow/flow.typ +++ b/tests/suite/layout/flow/flow.typ @@ -76,3 +76,7 @@ Hi #block(rect(width: 80%, height: 80pt), breakable: false) #lines(6) ] + +--- issue-5024-spill-backlog --- +#set page(columns: 2, height: 50pt) +#columns(2)[Hello] |
