Support transparent page fill (#4586)

Co-authored-by: Martin Haug <mhaug@live.de>

4 files changed, 12 insertions, 7 deletions

diff --git a/crates/typst-pdf/src/color_font.rs b/crates/typst-pdf/src/color_font.rs
index 201915b1..4889d915 100644
--- a/crates/typst-pdf/src/color_font.rs
+++ b/crates/typst-pdf/src/color_font.rs
@@ -243,7 +243,7 @@ impl ColorFontMap<()> {
             let width =
                 font.advance(gid).unwrap_or(Em::new(0.0)).get() * font.units_per_em();
             let instructions =
-                content::build(&mut self.resources, &frame, Some(width as f32));
+                content::build(&mut self.resources, &frame, None, Some(width as f32));
             color_font.glyphs.push(ColorGlyph { gid, instructions });
             color_font.glyph_indices.insert(gid, index);
 
diff --git a/crates/typst-pdf/src/content.rs b/crates/typst-pdf/src/content.rs
index da9e4ed4..d9830e43 100644
--- a/crates/typst-pdf/src/content.rs
+++ b/crates/typst-pdf/src/content.rs
@@ -36,6 +36,7 @@ use crate::{deflate_deferred, AbsExt, EmExt};
 pub fn build(
     resources: &mut Resources<()>,
     frame: &Frame,
+    fill: Option<Paint>,
     color_glyph_width: Option<f32>,
 ) -> Encoded {
     let size = frame.size();
@@ -53,6 +54,11 @@ pub fn build(
             .post_concat(Transform::translate(Abs::zero(), size.y)),
     );
 
+    if let Some(fill) = fill {
+        let shape = Geometry::Rect(frame.size()).filled(fill);
+        write_shape(&mut ctx, Point::zero(), &shape);
+    }
+
     // Encode the frame into the content stream.
     write_frame(&mut ctx, frame);
 
diff --git a/crates/typst-pdf/src/page.rs b/crates/typst-pdf/src/page.rs
index 2983f504..b07490cc 100644
--- a/crates/typst-pdf/src/page.rs
+++ b/crates/typst-pdf/src/page.rs
@@ -8,7 +8,7 @@ use pdf_writer::{
 };
 use typst::foundations::Label;
 use typst::introspection::Location;
-use typst::layout::{Abs, Frame};
+use typst::layout::{Abs, Page};
 use typst::model::{Destination, Numbering};
 use typst::text::Case;
 
@@ -33,7 +33,7 @@ pub fn traverse_pages(
             pages.push(None);
             skipped_pages += 1;
         } else {
-            let mut encoded = construct_page(&mut resources, &page.frame);
+            let mut encoded = construct_page(&mut resources, page);
             encoded.label = page
                 .numbering
                 .as_ref()
@@ -60,9 +60,8 @@ pub fn traverse_pages(
 
 /// Construct a page object.
 #[typst_macros::time(name = "construct page")]
-fn construct_page(out: &mut Resources<()>, frame: &Frame) -> EncodedPage {
-    let content = content::build(out, frame, None);
-
+fn construct_page(out: &mut Resources<()>, page: &Page) -> EncodedPage {
+    let content = content::build(out, &page.frame, page.fill_or_transparent(), None);
     EncodedPage { content, label: None }
 }
 
diff --git a/crates/typst-pdf/src/pattern.rs b/crates/typst-pdf/src/pattern.rs
index e06c04f8..d4f5a6e0 100644
--- a/crates/typst-pdf/src/pattern.rs
+++ b/crates/typst-pdf/src/pattern.rs
@@ -103,7 +103,7 @@ fn register_pattern(
     };
 
     // Render the body.
-    let content = content::build(&mut patterns.resources, pattern.frame(), None);
+    let content = content::build(&mut patterns.resources, pattern.frame(), None, None);
 
     let pdf_pattern = PdfPattern {
         transform,