Add bleed support to page layout

crates/typst-layout/src/pages/finalize.rs

@@ -15,6 +15,7 @@ pub fn finalize(
     LayoutedPage {
         inner,
         mut margin,
+        bleed,
         binding,
         two_sided,
         header,
@@ -34,33 +35,36 @@ pub fn finalize(
     }
 
     // Create a frame for the full page.
-    let mut frame = Frame::hard(inner.size() + margin.sum_by_axis());
+    let mut frame =
+        Frame::hard(inner.size() + margin.sum_by_axis() + bleed.sum_by_axis());
 
     // Add tags.
     for tag in tags.drain(..) {
         frame.push(Point::zero(), FrameItem::Tag(tag));
     }
 
+    let bleed_start = Point::new(bleed.left, bleed.top);
+
     // 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);
+        frame.push_frame(bleed_start, background);
     }
     if let Some(header) = header {
-        frame.push_frame(Point::with_x(margin.left), header);
+        frame.push_frame(bleed_start + Point::with_x(margin.left), header);
     }
 
     // Add the inner contents.
-    frame.push_frame(Point::new(margin.left, margin.top), inner);
+    frame.push_frame(bleed_start + 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);
+        let y = frame.height() - footer.height() - bleed.bottom;
+        frame.push_frame(Point::new(margin.left + bleed.left, y), footer);
     }
     if let Some(foreground) = foreground {
-        frame.push_frame(Point::zero(), foreground);
+        frame.push_frame(bleed_start + Point::zero(), foreground);
     }
 
     // Apply counter updates from within the page to the manual page counter.
@@ -70,5 +74,5 @@ pub fn finalize(
     let number = counter.logical();
     counter.step();
 
-    Ok(Page { frame, fill, numbering, supplement, number })
+    Ok(Page { frame, bleed, fill, numbering, supplement, number })
 }

crates/typst-layout/src/pages/run.rs

@@ -28,6 +28,7 @@ use crate::flow::{layout_flow, FlowMode};
 pub struct LayoutedPage {
     pub inner: Frame,
     pub margin: Sides<Abs>,
+    pub bleed: Sides<Abs>,
     pub binding: Binding,
     pub two_sided: bool,
     pub header: Option<Frame>,
@@ -123,6 +124,12 @@ fn layout_page_run_impl(
         .resolve(styles)
         .relative_to(size);
 
+    let bleed = PageElem::bleed_in(styles)
+        .sides
+        .map(|side| side.and_then(Smart::custom).unwrap_or(Rel::zero()))
+        .resolve(styles)
+        .relative_to(size);
+
     let fill = PageElem::fill_in(styles);
     let foreground = PageElem::foreground_in(styles);
     let background = PageElem::background_in(styles);
@@ -215,6 +222,7 @@ fn layout_page_run_impl(
             background: layout_marginal(background, full_size, mid)?,
             foreground: layout_marginal(foreground, full_size, mid)?,
             margin,
+            bleed,
             binding,
             two_sided,
         });

crates/typst-library/src/layout/page.rs

@@ -148,6 +148,46 @@ pub struct PageElem {
     #[ghost]
     pub margin: Margin,
 
+    /// The page's bleed margin.
+    ///
+    /// The bleed is a part of the content that extends beyond the edge of the
+    /// final trimmed page. It ensures that there are no unprinted edges in the
+    /// final product, even if there's a slight misalignment during trimming.
+    ///
+    /// - `{auto}`: The bleed is set to 0mm on each side.
+    /// - A single length: The same bleed on all sides.
+    /// - A dictionary: With a dictionary, the bleed can be set individually.
+    ///   The dictionary can contain the following keys in order of precedence:
+    ///   - `top`: The top bleed.
+    ///   - `right`: The right bleed.
+    ///   - `bottom`: The bottom bleed.
+    ///   - `left`: The left bleed.
+    ///   - `inside`: The bleed at the inner side of the page (where the
+    ///     [binding]($page.binding) is).
+    ///   - `outside`: The bleed at the outer side of the page (opposite to the
+    ///     [binding]($page.binding)).
+    ///   - `x`: The horizontal bleeds.
+    ///   - `y`: The vertical bleeds.
+    ///   - `rest`: The bleeds on all sides except those for which the
+    ///     dictionary explicitly sets a size.
+    ///
+    /// The values for `left` and `right` are mutually exclusive with
+    /// the values for `inside` and `outside`.
+    ///
+    /// On PDF output, if bleed is different of zero, it sets a TrimBox and a
+    /// BleedBox for the page.
+    ///
+    /// ```example
+    /// #set page(
+    ///   width: 3cm,
+    ///   height: 4cm,
+    ///   bleed: 5mm,
+    ///   background: rect(width: 100%, height: 100%, fill: aqua),
+    /// )
+    /// ```
+    #[ghost]
+    pub bleed: Margin,
+
     /// On which side the pages will be bound.
     ///
     /// - `{auto}`: Equivalent to `left` if the [text direction]($text.dir)
@@ -467,6 +507,8 @@ pub struct PagedDocument {
 pub struct Page {
     /// The frame that defines the page.
     pub frame: Frame,
+    /// The bleed amount to be added on each side of the page.
+    pub bleed: Sides<Abs>,
     /// How the page is filled.
     ///
     /// - When `None`, the background is transparent.

crates/typst-pdf/src/convert.rs

@@ -7,7 +7,7 @@ use krilla::configure::{Configuration, ValidationError, Validator};
 use krilla::destination::{NamedDestination, XyzDestination};
 use krilla::embed::EmbedError;
 use krilla::error::KrillaError;
-use krilla::geom::PathBuilder;
+use krilla::geom::{PathBuilder, Rect};
 use krilla::page::{PageLabel, PageSettings};
 use krilla::surface::Surface;
 use krilla::{Document, SerializeSettings};
@@ -16,7 +16,7 @@ use typst_library::diag::{bail, error, SourceDiagnostic, SourceResult};
 use typst_library::foundations::{NativeElement, Repr};
 use typst_library::introspection::Location;
 use typst_library::layout::{
-    Abs, Frame, FrameItem, GroupItem, PagedDocument, Size, Transform,
+    Abs, Frame, FrameItem, GroupItem, PagedDocument, Sides, Size, Transform,
 };
 use typst_library::model::HeadingElem;
 use typst_library::text::{Font, Lang};
@@ -81,6 +81,22 @@ fn convert_pages(gc: &mut GlobalContext, document: &mut Document) -> SourceResul
                 typst_page.frame.height().to_f32(),
             );
 
+            if typst_page.bleed != Sides::splat(Abs::zero()) {
+                settings = settings
+                    .with_bleed_box(Rect::from_xywh(
+                        0.0,
+                        0.0,
+                        typst_page.frame.width().to_f32(),
+                        typst_page.frame.height().to_f32(),
+                    ))
+                    .with_trim_box(Rect::from_ltrb(
+                        typst_page.bleed.left.to_f32(),
+                        typst_page.bleed.top.to_f32(),
+                        (typst_page.frame.width() - typst_page.bleed.right).to_f32(),
+                        (typst_page.frame.height() - typst_page.bleed.bottom).to_f32(),
+                    ));
+            }
+
             if let Some(label) = typst_page
                 .numbering
                 .as_ref()

tests/suite/layout/page.typ

@@ -348,6 +348,26 @@ A
   A
 ]
 
+--- page-bleed ---
+#set page(
+  bleed: 20pt,
+  margin: 20pt,
+  height: 80pt,
+  width: 80pt,
+  background: rect(width: 100%, height: 100%, fill: gray),
+)
+#rect(width: 100%, height: 100%, fill: black)
+
+--- page-bleed-content-bleeding ---
+#set page(
+  bleed: 20pt,
+  margin: 20pt,
+  height: 80pt,
+  width: 80pt,
+)
+#set align(center + horizon)
+#rect(width: 100pt, height: 100pt, fill: black)
+
 --- issue-2631-page-header-ordering ---
 #set text(6pt)
 #show heading: set text(6pt, weight: "regular")