Split out four new crates (#5302)

1 files changed, 73 insertions, 0 deletions

diff --git a/crates/typst-layout/src/pages/finalize.rs b/crates/typst-layout/src/pages/finalize.rs
new file mode 100644
index 00000000..8df6cb16
--- /dev/null
+++ b/crates/typst-layout/src/pages/finalize.rs
@@ -0,0 +1,73 @@
+use typst_library::diag::SourceResult;
+use typst_library::engine::Engine;
+use typst_library::introspection::{ManualPageCounter, Tag};
+use typst_library::layout::{Frame, FrameItem, Page, Point};
+
+use super::LayoutedPage;
+
+/// Piece together the inner page frame and the marginals. We can only do this
+/// at the very end because inside/outside margins require knowledge of the
+/// physical page number, which is unknown during parallel layout.
+pub fn finalize(
+    engine: &mut Engine,
+    counter: &mut ManualPageCounter,
+    tags: &mut Vec<Tag>,
+    LayoutedPage {
+        inner,
+        mut margin,
+        binding,
+        two_sided,
+        header,
+        footer,
+        background,
+        foreground,
+        fill,
+        numbering,
+    }: LayoutedPage,
+) -> SourceResult<Page> {
+    // If two sided, left becomes inside and right becomes outside.
+    // Thus, for left-bound pages, we want to swap on even pages and
+    // for right-bound pages, we want to swap on odd pages.
+    if two_sided && binding.swap(counter.physical()) {
+        std::mem::swap(&mut margin.left, &mut margin.right);
+    }
+
+    // Create a frame for the full page.
+    let mut frame = Frame::hard(inner.size() + margin.sum_by_axis());
+
+    // Add tags.
+    for tag in tags.drain(..) {
+        frame.push(Point::zero(), FrameItem::Tag(tag));
+    }
+
+    // Add the "before" marginals. The order in which we push things here is
+    // important as it affects the relative ordering of introspectable elements
+    // and thus how counters resolve.
+    if let Some(background) = background {
+        frame.push_frame(Point::zero(), background);
+    }
+    if let Some(header) = header {
+        frame.push_frame(Point::with_x(margin.left), header);
+    }
+
+    // Add the inner contents.
+    frame.push_frame(Point::new(margin.left, margin.top), inner);
+
+    // Add the "after" marginals.
+    if let Some(footer) = footer {
+        let y = frame.height() - footer.height();
+        frame.push_frame(Point::new(margin.left, y), footer);
+    }
+    if let Some(foreground) = foreground {
+        frame.push_frame(Point::zero(), foreground);
+    }
+
+    // Apply counter updates from within the page to the manual page counter.
+    counter.visit(engine, &frame)?;
+
+    // Get this page's number and then bump the counter for the next page.
+    let number = counter.logical();
+    counter.step();
+
+    Ok(Page { frame, fill, numbering, number })
+}