Refactor PDF export a bit

8 files changed, 132 insertions, 160 deletions

diff --git a/crates/typst/src/export/pdf/color.rs b/crates/typst/src/export/pdf/color.rs
index eb27f969..fccaafab 100644
--- a/crates/typst/src/export/pdf/color.rs
+++ b/crates/typst/src/export/pdf/color.rs
@@ -1,5 +1,4 @@
-use std::sync::Arc;
-
+use once_cell::sync::Lazy;
 use pdf_writer::types::DeviceNSubtype;
 use pdf_writer::{writers, Chunk, Dict, Filter, Name, Ref};
 
@@ -27,13 +26,18 @@ const HSL_S: Name<'static> = Name(b"S");
 const HSL_L: Name<'static> = Name(b"L");
 
 // The ICC profiles.
-const SRGB_ICC: &[u8] = include_bytes!("./icc/sRGB-v4.icc");
-const GRAY_ICC: &[u8] = include_bytes!("./icc/sGrey-v4.icc");
+static SRGB_ICC_DEFLATED: Lazy<Vec<u8>> =
+    Lazy::new(|| deflate(include_bytes!("icc/sRGB-v4.icc")));
+static GRAY_ICC_DEFLATED: Lazy<Vec<u8>> =
+    Lazy::new(|| deflate(include_bytes!("icc/sGrey-v4.icc")));
 
 // The PostScript functions for color spaces.
-const OKLAB_SOURCE: &str = include_str!("./postscript/oklab.ps");
-const HSL_SOURCE: &str = include_str!("./postscript/hsl.ps");
-const HSV_SOURCE: &str = include_str!("./postscript/hsv.ps");
+static OKLAB_DEFLATED: Lazy<Vec<u8>> =
+    Lazy::new(|| deflate(minify(include_str!("postscript/oklab.ps")).as_bytes()));
+static HSV_DEFLATED: Lazy<Vec<u8>> =
+    Lazy::new(|| deflate(minify(include_str!("postscript/hsl.ps")).as_bytes()));
+static HSL_DEFLATED: Lazy<Vec<u8>> =
+    Lazy::new(|| deflate(minify(include_str!("postscript/hsv.ps")).as_bytes()));
 
 /// The color spaces present in the PDF document
 #[derive(Default)]
@@ -161,87 +165,54 @@ impl ColorSpaces {
 
     /// Write the necessary color spaces functions and ICC profiles to the
     /// PDF file.
-    pub fn write_functions(&self, writer: &mut Chunk) {
-        // Write the Oklab function & color space
+    pub fn write_functions(&self, chunk: &mut Chunk) {
+        // Write the Oklab function & color space.
         if let Some(oklab) = self.oklab {
-            let code = oklab_function();
-            writer
-                .post_script_function(oklab, &code)
+            chunk
+                .post_script_function(oklab, &OKLAB_DEFLATED)
                 .domain([0.0, 1.0, 0.0, 1.0, 0.0, 1.0])
                 .range([0.0, 1.0, 0.0, 1.0, 0.0, 1.0])
                 .filter(Filter::FlateDecode);
         }
 
-        // Write the HSV function & color space
+        // Write the HSV function & color space.
         if let Some(hsv) = self.hsv {
-            let code = hsv_function();
-            writer
-                .post_script_function(hsv, &code)
+            chunk
+                .post_script_function(hsv, &HSV_DEFLATED)
                 .domain([0.0, 1.0, 0.0, 1.0, 0.0, 1.0])
                 .range([0.0, 1.0, 0.0, 1.0, 0.0, 1.0])
                 .filter(Filter::FlateDecode);
         }
 
-        // Write the HSL function & color space
+        // Write the HSL function & color space.
         if let Some(hsl) = self.hsl {
-            let code = hsl_function();
-            writer
-                .post_script_function(hsl, &code)
+            chunk
+                .post_script_function(hsl, &HSL_DEFLATED)
                 .domain([0.0, 1.0, 0.0, 1.0, 0.0, 1.0])
                 .range([0.0, 1.0, 0.0, 1.0, 0.0, 1.0])
                 .filter(Filter::FlateDecode);
         }
 
-        // Write the sRGB color space
+        // Write the sRGB color space.
         if let Some(srgb) = self.srgb {
-            let profile = srgb_icc();
-            writer
-                .icc_profile(srgb, &profile)
+            chunk
+                .icc_profile(srgb, &SRGB_ICC_DEFLATED)
                 .n(3)
-                .range([0.0, 1.0, 0.0, 1.0, 0.0, 1.0]);
+                .range([0.0, 1.0, 0.0, 1.0, 0.0, 1.0])
+                .filter(Filter::FlateDecode);
         }
 
-        // Write the gray color space
+        // Write the gray color space.
         if let Some(gray) = self.d65_gray {
-            let profile = gray_icc();
-            writer.icc_profile(gray, &profile).n(1).range([0.0, 1.0]);
+            chunk
+                .icc_profile(gray, &GRAY_ICC_DEFLATED)
+                .n(1)
+                .range([0.0, 1.0])
+                .filter(Filter::FlateDecode);
         }
     }
 }
 
-/// Deflated sRGB ICC profile
-#[comemo::memoize]
-fn srgb_icc() -> Arc<Vec<u8>> {
-    Arc::new(deflate(SRGB_ICC))
-}
-
-/// Deflated gray ICC profile
-#[comemo::memoize]
-fn gray_icc() -> Arc<Vec<u8>> {
-    Arc::new(deflate(GRAY_ICC))
-}
-
-/// Deflated Oklab PostScript function
-#[comemo::memoize]
-fn oklab_function() -> Arc<Vec<u8>> {
-    let code = minify(OKLAB_SOURCE);
-    Arc::new(deflate(code.as_bytes()))
-}
-
-/// Deflated HSV PostScript function
-#[comemo::memoize]
-fn hsv_function() -> Arc<Vec<u8>> {
-    let code = minify(HSV_SOURCE);
-    Arc::new(deflate(code.as_bytes()))
-}
-
-/// Deflated HSL PostScript function
-#[comemo::memoize]
-fn hsl_function() -> Arc<Vec<u8>> {
-    let code = minify(HSL_SOURCE);
-    Arc::new(deflate(code.as_bytes()))
-}
-
 /// This function removes comments, line spaces and carriage returns from a
 /// PostScript program. This is necessary to optimize the size of the PDF file.
 fn minify(source: &str) -> String {
diff --git a/crates/typst/src/export/pdf/extg.rs b/crates/typst/src/export/pdf/extg.rs
index 47393b54..f7bd116d 100644
--- a/crates/typst/src/export/pdf/extg.rs
+++ b/crates/typst/src/export/pdf/extg.rs
@@ -1,23 +1,21 @@
-use pdf_writer::Finish;
-
-use crate::export::pdf::PdfContext;
+use super::PdfContext;
 
 /// A PDF external graphics state.
 #[derive(Clone, Copy, Debug, Eq, PartialEq, Hash)]
-pub struct ExternalGraphicsState {
+pub struct ExtGState {
     // In the range 0-255, needs to be divided before being written into the graphics state!
     pub stroke_opacity: u8,
     // In the range 0-255, needs to be divided before being written into the graphics state!
     pub fill_opacity: u8,
 }
 
-impl Default for ExternalGraphicsState {
+impl Default for ExtGState {
     fn default() -> Self {
         Self { stroke_opacity: 255, fill_opacity: 255 }
     }
 }
 
-impl ExternalGraphicsState {
+impl ExtGState {
     pub fn uses_opacities(&self) -> bool {
         self.stroke_opacity != 255 || self.fill_opacity != 255
     }
@@ -26,13 +24,12 @@ impl ExternalGraphicsState {
 /// Embed all used external graphics states into the PDF.
 #[tracing::instrument(skip_all)]
 pub fn write_external_graphics_states(ctx: &mut PdfContext) {
-    for external_gs in ctx.ext_gs_map.items() {
-        let gs_ref = ctx.alloc.bump();
-        ctx.ext_gs_refs.push(gs_ref);
-
-        let mut gs = ctx.writer.ext_graphics(gs_ref);
-        gs.non_stroking_alpha(external_gs.fill_opacity as f32 / 255.0)
+    for external_gs in ctx.extg_map.items() {
+        let id = ctx.alloc.bump();
+        ctx.ext_gs_refs.push(id);
+        ctx.pdf
+            .ext_graphics(id)
+            .non_stroking_alpha(external_gs.fill_opacity as f32 / 255.0)
             .stroking_alpha(external_gs.stroke_opacity as f32 / 255.0);
-        gs.finish();
     }
 }
diff --git a/crates/typst/src/export/pdf/font.rs b/crates/typst/src/export/pdf/font.rs
index e1faf1b1..bd7cfb31 100644
--- a/crates/typst/src/export/pdf/font.rs
+++ b/crates/typst/src/export/pdf/font.rs
@@ -58,7 +58,7 @@ pub fn write_fonts(ctx: &mut PdfContext) {
         };
 
         // Write the base font object referencing the CID font.
-        ctx.writer
+        ctx.pdf
             .type0_font(type0_ref)
             .base_font(Name(base_font_type0.as_bytes()))
             .encoding_predefined(Name(b"Identity-H"))
@@ -66,7 +66,7 @@ pub fn write_fonts(ctx: &mut PdfContext) {
             .to_unicode(cmap_ref);
 
         // Write the CID font referencing the font descriptor.
-        let mut cid = ctx.writer.cid_font(cid_ref);
+        let mut cid = ctx.pdf.cid_font(cid_ref);
         cid.subtype(if is_cff { CidFontType::Type0 } else { CidFontType::Type2 });
         cid.base_font(Name(base_font.as_bytes()));
         cid.system_info(SYSTEM_INFO);
@@ -125,7 +125,7 @@ pub fn write_fonts(ctx: &mut PdfContext) {
         let stem_v = 10.0 + 0.244 * (f32::from(ttf.weight().to_number()) - 50.0);
 
         // Write the font descriptor (contains metrics about the font).
-        let mut font_descriptor = ctx.writer.font_descriptor(descriptor_ref);
+        let mut font_descriptor = ctx.pdf.font_descriptor(descriptor_ref);
         font_descriptor
             .name(Name(base_font.as_bytes()))
             .flags(flags)
@@ -147,13 +147,13 @@ pub fn write_fonts(ctx: &mut PdfContext) {
         // Write the /ToUnicode character map, which maps glyph ids back to
         // unicode codepoints to enable copying out of the PDF.
         let cmap = create_cmap(ttf, glyph_set);
-        ctx.writer.cmap(cmap_ref, &cmap.finish());
+        ctx.pdf.cmap(cmap_ref, &cmap.finish());
 
         // Subset and write the font's bytes.
         let glyphs: Vec<_> = glyph_set.keys().copied().collect();
         let data = subset_font(font, &glyphs);
 
-        let mut stream = ctx.writer.stream(data_ref, &data);
+        let mut stream = ctx.pdf.stream(data_ref, &data);
         stream.filter(Filter::FlateDecode);
         if is_cff {
             stream.pair(Name(b"Subtype"), Name(b"CIDFontType0C"));
diff --git a/crates/typst/src/export/pdf/gradient.rs b/crates/typst/src/export/pdf/gradient.rs
index 23ab687c..842c7666 100644
--- a/crates/typst/src/export/pdf/gradient.rs
+++ b/crates/typst/src/export/pdf/gradient.rs
@@ -35,7 +35,7 @@ pub fn write_gradients(ctx: &mut PdfContext) {
         let mut shading_pattern = match &gradient {
             Gradient::Linear(linear) => {
                 let shading_function = shading_function(ctx, &gradient);
-                let mut shading_pattern = ctx.writer.shading_pattern(shading);
+                let mut shading_pattern = ctx.pdf.shading_pattern(shading);
                 let mut shading = shading_pattern.function_shading();
                 shading.shading_type(FunctionShadingType::Axial);
 
@@ -108,7 +108,7 @@ fn shading_function(ctx: &mut PdfContext, gradient: &Gradient) -> Ref {
 
                     // These need to be individual function to encode 360.0 correctly.
                     let func1 = ctx.alloc.bump();
-                    ctx.writer
+                    ctx.pdf
                         .exponential_function(func1)
                         .range(gradient.space().range())
                         .c0(gradient.space().convert(first.0))
@@ -117,7 +117,7 @@ fn shading_function(ctx: &mut PdfContext, gradient: &Gradient) -> Ref {
                         .n(1.0);
 
                     let func2 = ctx.alloc.bump();
-                    ctx.writer
+                    ctx.pdf
                         .exponential_function(func2)
                         .range(gradient.space().range())
                         .c0([1.0, s1 * (1.0 - t) + s2 * t, x1 * (1.0 - t) + x2 * t])
@@ -126,7 +126,7 @@ fn shading_function(ctx: &mut PdfContext, gradient: &Gradient) -> Ref {
                         .n(1.0);
 
                     let func3 = ctx.alloc.bump();
-                    ctx.writer
+                    ctx.pdf
                         .exponential_function(func3)
                         .range(gradient.space().range())
                         .c0([0.0, s1 * (1.0 - t) + s2 * t, x1 * (1.0 - t) + x2 * t])
@@ -157,7 +157,7 @@ fn shading_function(ctx: &mut PdfContext, gradient: &Gradient) -> Ref {
     bounds.pop();
 
     // Create the stitching function.
-    ctx.writer
+    ctx.pdf
         .stitching_function(function)
         .domain([0.0, 1.0])
         .range(gradient.space().range())
@@ -178,7 +178,7 @@ fn single_gradient(
 ) -> Ref {
     let reference = ctx.alloc.bump();
 
-    ctx.writer
+    ctx.pdf
         .exponential_function(reference)
         .range(color_space.range())
         .c0(color_space.convert(first_color))
diff --git a/crates/typst/src/export/pdf/image.rs b/crates/typst/src/export/pdf/image.rs
index 12c5fb34..cce75bc3 100644
--- a/crates/typst/src/export/pdf/image.rs
+++ b/crates/typst/src/export/pdf/image.rs
@@ -15,26 +15,28 @@ use crate::{
 pub fn write_images(ctx: &mut PdfContext) {
     for image in ctx.image_map.items() {
         let image_ref = ctx.alloc.bump();
-        let icc_ref = ctx.alloc.bump();
         ctx.image_refs.push(image_ref);
 
-        let width = image.width();
-        let height = image.height();
-
         // Add the primary image.
         match image.kind() {
             ImageKind::Raster(raster) => {
                 // TODO: Error if image could not be encoded.
-                let (data, filter, has_color) = encode_image(raster);
-                let mut image = ctx.writer.image_xobject(image_ref, &data);
+                let (data, filter, has_color) = encode_raster_image(raster);
+                let width = image.width();
+                let height = image.height();
+
+                let mut image = ctx.pdf.image_xobject(image_ref, &data);
                 image.filter(filter);
                 image.width(width as i32);
                 image.height(height as i32);
                 image.bits_per_component(8);
 
+                let mut icc_ref = None;
                 let space = image.color_space();
                 if raster.icc().is_some() {
-                    space.icc_based(icc_ref);
+                    let id = ctx.alloc.bump();
+                    space.icc_based(id);
+                    icc_ref = Some(id);
                 } else if has_color {
                     ctx.colors.write(ColorSpace::Srgb, space, &mut ctx.alloc);
                 } else {
@@ -49,7 +51,7 @@ pub fn write_images(ctx: &mut PdfContext) {
                     image.s_mask(mask_ref);
                     image.finish();
 
-                    let mut mask = ctx.writer.image_xobject(mask_ref, &alpha_data);
+                    let mut mask = ctx.pdf.image_xobject(mask_ref, &alpha_data);
                     mask.filter(alpha_filter);
                     mask.width(width as i32);
                     mask.height(height as i32);
@@ -59,9 +61,9 @@ pub fn write_images(ctx: &mut PdfContext) {
                     image.finish();
                 }
 
-                if let Some(icc) = raster.icc() {
+                if let (Some(icc), Some(icc_ref)) = (raster.icc(), icc_ref) {
                     let compressed = deflate(icc);
-                    let mut stream = ctx.writer.icc_profile(icc_ref, &compressed);
+                    let mut stream = ctx.pdf.icc_profile(icc_ref, &compressed);
                     stream.filter(Filter::FlateDecode);
                     if has_color {
                         stream.n(3);
@@ -79,7 +81,7 @@ pub fn write_images(ctx: &mut PdfContext) {
                     let next_ref = svg2pdf::convert_tree_into(
                         tree,
                         svg2pdf::Options::default(),
-                        &mut ctx.writer,
+                        &mut ctx.pdf,
                         image_ref,
                     );
                     ctx.alloc = next_ref;
@@ -95,7 +97,7 @@ pub fn write_images(ctx: &mut PdfContext) {
 /// Skips the alpha channel as that's encoded separately.
 #[comemo::memoize]
 #[tracing::instrument(skip_all)]
-fn encode_image(image: &RasterImage) -> (Arc<Vec<u8>>, Filter, bool) {
+fn encode_raster_image(image: &RasterImage) -> (Arc<Vec<u8>>, Filter, bool) {
     let dynamic = image.dynamic();
     match (image.format(), dynamic) {
         // 8-bit gray JPEG.
diff --git a/crates/typst/src/export/pdf/mod.rs b/crates/typst/src/export/pdf/mod.rs
index 587c5361..51784fbc 100644
--- a/crates/typst/src/export/pdf/mod.rs
+++ b/crates/typst/src/export/pdf/mod.rs
@@ -30,7 +30,7 @@ use crate::geom::{Abs, Dir, Em};
 use crate::image::Image;
 use crate::model::Introspector;
 
-use extg::ExternalGraphicsState;
+use extg::ExtGState;
 
 /// Export a document into a PDF file.
 ///
@@ -45,36 +45,57 @@ pub fn pdf(document: &Document) -> Vec<u8> {
     extg::write_external_graphics_states(&mut ctx);
     page::write_page_tree(&mut ctx);
     write_catalog(&mut ctx);
-    ctx.writer.finish()
+    ctx.pdf.finish()
 }
 
 /// Context for exporting a whole PDF document.
 pub struct PdfContext<'a> {
+    /// The document that we're currently exporting.
     document: &'a Document,
+    /// An introspector for the document, used to resolve locations links and
+    /// the document outline.
     introspector: Introspector,
-    writer: Pdf,
-    colors: ColorSpaces,
+
+    /// The writer we are writing the PDF into.
+    pdf: Pdf,
+    /// Content of exported pages.
     pages: Vec<Page>,
-    page_heights: Vec<f32>,
+    /// For each font a mapping from used glyphs to their text representation.
+    /// May contain multiple chars in case of ligatures or similar things. The
+    /// same glyph can have a different text representation within one document,
+    /// then we just save the first one. The resulting strings are used for the
+    /// PDF's /ToUnicode map for glyphs that don't have an entry in the font's
+    /// cmap. This is important for copy-paste and searching.
+    glyph_sets: HashMap<Font, BTreeMap<u16, EcoString>>,
+    /// The number of glyphs for all referenced languages in the document.
+    /// We keep track of this to determine the main document language.
+    languages: HashMap<Lang, usize>,
+
+    /// Allocator for indirect reference IDs.
     alloc: Ref,
+    /// The ID of the page tree.
     page_tree_ref: Ref,
+    /// The IDs of written pages.
+    page_refs: Vec<Ref>,
+    /// The IDs of written fonts.
     font_refs: Vec<Ref>,
+    /// The IDs of written images.
     image_refs: Vec<Ref>,
+    /// The IDs of written gradients.
     gradient_refs: Vec<Ref>,
+    /// The IDs of written external graphics states.
     ext_gs_refs: Vec<Ref>,
-    page_refs: Vec<Ref>,
+    /// Handles color space writing.
+    colors: ColorSpaces,
+
+    /// Deduplicates fonts used across the document.
     font_map: Remapper<Font>,
+    /// Deduplicates images used across the document.
     image_map: Remapper<Image>,
+    /// Deduplicates gradients used across the document.
     gradient_map: Remapper<PdfGradient>,
-    ext_gs_map: Remapper<ExternalGraphicsState>,
-    /// For each font a mapping from used glyphs to their text representation.
-    /// May contain multiple chars in case of ligatures or similar things. The
-    /// same glyph can have a different text representation within one document,
-    /// then we just save the first one. The resulting strings are used for the
-    /// PDF's /ToUnicode map for glyphs that don't have an entry in the font's
-    /// cmap. This is important for copy-paste and searching.
-    glyph_sets: HashMap<Font, BTreeMap<u16, EcoString>>,
-    languages: HashMap<Lang, usize>,
+    /// Deduplicates external graphics states used across the document.
+    extg_map: Remapper<ExtGState>,
 }
 
 impl<'a> PdfContext<'a> {
@@ -84,10 +105,10 @@ impl<'a> PdfContext<'a> {
         Self {
             document,
             introspector: Introspector::new(&document.pages),
-            writer: Pdf::new(),
-            colors: ColorSpaces::default(),
+            pdf: Pdf::new(),
             pages: vec![],
-            page_heights: vec![],
+            glyph_sets: HashMap::new(),
+            languages: HashMap::new(),
             alloc,
             page_tree_ref,
             page_refs: vec![],
@@ -95,12 +116,11 @@ impl<'a> PdfContext<'a> {
             image_refs: vec![],
             gradient_refs: vec![],
             ext_gs_refs: vec![],
+            colors: ColorSpaces::default(),
             font_map: Remapper::new(),
             image_map: Remapper::new(),
             gradient_map: Remapper::new(),
-            ext_gs_map: Remapper::new(),
-            glyph_sets: HashMap::new(),
-            languages: HashMap::new(),
+            extg_map: Remapper::new(),
         }
     }
 }
@@ -127,7 +147,7 @@ fn write_catalog(ctx: &mut PdfContext) {
     let page_labels = write_page_labels(ctx);
 
     // Write the document information.
-    let mut info = ctx.writer.document_info(ctx.alloc.bump());
+    let mut info = ctx.pdf.document_info(ctx.alloc.bump());
     let mut xmp = XmpWriter::new();
     if let Some(title) = &ctx.document.title {
         info.title(TextStr(title));
@@ -160,13 +180,13 @@ fn write_catalog(ctx: &mut PdfContext) {
 
     let xmp_buf = xmp.finish(None);
     let meta_ref = ctx.alloc.bump();
-    let mut meta_stream = ctx.writer.stream(meta_ref, xmp_buf.as_bytes());
-    meta_stream.pair(Name(b"Type"), Name(b"Metadata"));
-    meta_stream.pair(Name(b"Subtype"), Name(b"XML"));
-    meta_stream.finish();
+    ctx.pdf
+        .stream(meta_ref, xmp_buf.as_bytes())
+        .pair(Name(b"Type"), Name(b"Metadata"))
+        .pair(Name(b"Subtype"), Name(b"XML"));
 
     // Write the document catalog.
-    let mut catalog = ctx.writer.catalog(ctx.alloc.bump());
+    let mut catalog = ctx.pdf.catalog(ctx.alloc.bump());
     catalog.pages(ctx.page_tree_ref);
     catalog.viewer_preferences().direction(dir);
     catalog.pair(Name(b"Metadata"), meta_ref);
@@ -215,7 +235,7 @@ fn write_page_labels(ctx: &mut PdfContext) -> Vec<(NonZeroUsize, Ref)> {
         }
 
         let id = ctx.alloc.bump();
-        let mut entry = ctx.writer.indirect(id).start::<PageLabel>();
+        let mut entry = ctx.pdf.indirect(id).start::<PageLabel>();
 
         // Only add what is actually provided. Don't add empty prefix string if
         // it wasn't given for example.
@@ -309,17 +329,3 @@ impl EmExt for Em {
         1000.0 * self.get() as f32
     }
 }
-
-/// Additional methods for [`Ref`].
-trait RefExt {
-    /// Bump the reference up by one and return the previous one.
-    fn bump(&mut self) -> Self;
-}
-
-impl RefExt for Ref {
-    fn bump(&mut self) -> Self {
-        let prev = *self;
-        *self = Self::new(prev.get() + 1);
-        prev
-    }
-}
diff --git a/crates/typst/src/export/pdf/outline.rs b/crates/typst/src/export/pdf/outline.rs
index 58db7a93..7aa15c41 100644
--- a/crates/typst/src/export/pdf/outline.rs
+++ b/crates/typst/src/export/pdf/outline.rs
@@ -92,7 +92,7 @@ pub fn write_outline(ctx: &mut PdfContext) -> Option<Ref> {
         prev_ref = Some(write_outline_item(ctx, node, root_id, prev_ref, i + 1 == len));
     }
 
-    ctx.writer
+    ctx.pdf
         .outline(root_id)
         .first(start_ref)
         .last(Ref::new(ctx.alloc.get() - 1))
@@ -140,7 +140,7 @@ fn write_outline_item(
     let id = ctx.alloc.bump();
     let next_ref = Ref::new(id.get() + node.len() as i32);
 
-    let mut outline = ctx.writer.outline_item(id);
+    let mut outline = ctx.pdf.outline_item(id);
     outline.parent(parent_ref);
 
     if !is_last {
@@ -164,11 +164,11 @@ fn write_outline_item(
     let loc = node.element.location().unwrap();
     let pos = ctx.introspector.position(loc);
     let index = pos.page.get() - 1;
-    if let Some(&height) = ctx.page_heights.get(index) {
+    if let Some(page) = ctx.pages.get(index) {
         let y = (pos.point.y - Abs::pt(10.0)).max(Abs::zero());
         outline.dest().page(ctx.page_refs[index]).xyz(
             pos.point.x.to_f32(),
-            height - y.to_f32(),
+            (page.size.y - y).to_f32(),
             None,
         );
     }
diff --git a/crates/typst/src/export/pdf/page.rs b/crates/typst/src/export/pdf/page.rs
index ef023f22..412d753d 100644
--- a/crates/typst/src/export/pdf/page.rs
+++ b/crates/typst/src/export/pdf/page.rs
@@ -8,7 +8,7 @@ use pdf_writer::types::{
 use pdf_writer::{Content, Filter, Finish, Name, Rect, Ref, Str};
 
 use super::color::PaintEncode;
-use super::extg::ExternalGraphicsState;
+use super::extg::ExtGState;
 use super::{deflate, AbsExt, EmExt, PdfContext};
 use crate::doc::{Destination, Frame, FrameItem, GroupItem, Meta, TextItem};
 use crate::eval::Repr;
@@ -32,7 +32,6 @@ pub fn construct_pages(ctx: &mut PdfContext, frames: &[Frame]) {
 pub fn construct_page(ctx: &mut PdfContext, frame: &Frame) {
     let page_ref = ctx.alloc.bump();
     ctx.page_refs.push(page_ref);
-    ctx.page_heights.push(frame.height().to_f32());
 
     let mut ctx = PageContext {
         parent: ctx,
@@ -81,7 +80,7 @@ pub fn write_page_tree(ctx: &mut PdfContext) {
         write_page(ctx, i);
     }
 
-    let mut pages = ctx.writer.pages(ctx.page_tree_ref);
+    let mut pages = ctx.pdf.pages(ctx.page_tree_ref);
     pages
         .count(ctx.page_refs.len() as i32)
         .kids(ctx.page_refs.iter().copied());
@@ -115,7 +114,7 @@ pub fn write_page_tree(ctx: &mut PdfContext) {
     patterns.finish();
 
     let mut ext_gs_states = resources.ext_g_states();
-    for (gs_ref, gs) in ctx.ext_gs_map.pdf_indices(&ctx.ext_gs_refs) {
+    for (gs_ref, gs) in ctx.extg_map.pdf_indices(&ctx.ext_gs_refs) {
         let name = eco_format!("Gs{}", gs);
         ext_gs_states.pair(Name(name.as_bytes()), gs_ref);
     }
@@ -125,7 +124,7 @@ pub fn write_page_tree(ctx: &mut PdfContext) {
     pages.finish();
 
     // Write all of the functions used by the document.
-    ctx.colors.write_functions(&mut ctx.writer);
+    ctx.colors.write_functions(&mut ctx.pdf);
 }
 
 /// Write a page tree node.
@@ -134,7 +133,7 @@ fn write_page(ctx: &mut PdfContext, i: usize) {
     let page = &ctx.pages[i];
     let content_id = ctx.alloc.bump();
 
-    let mut page_writer = ctx.writer.page(page.id);
+    let mut page_writer = ctx.pdf.page(page.id);
     page_writer.parent(ctx.page_tree_ref);
 
     let w = page.size.x.to_f32();
@@ -172,13 +171,13 @@ fn write_page(ctx: &mut PdfContext, i: usize) {
 
         let index = pos.page.get() - 1;
         let y = (pos.point.y - Abs::pt(10.0)).max(Abs::zero());
-        if let Some(&height) = ctx.page_heights.get(index) {
+        if let Some(page) = ctx.pages.get(index) {
             annotation
                 .action()
                 .action_type(ActionType::GoTo)
                 .destination()
                 .page(ctx.page_refs[index])
-                .xyz(pos.point.x.to_f32(), height - y.to_f32(), None);
+                .xyz(pos.point.x.to_f32(), (page.size.y - y).to_f32(), None);
         }
     }
 
@@ -186,7 +185,7 @@ fn write_page(ctx: &mut PdfContext, i: usize) {
     page_writer.finish();
 
     let data = deflate(&page.content);
-    ctx.writer.stream(content_id, &data).filter(Filter::FlateDecode);
+    ctx.pdf.stream(content_id, &data).filter(Filter::FlateDecode);
 }
 
 /// Data for an exported page.
@@ -231,7 +230,7 @@ struct State {
     font: Option<(Font, Abs)>,
     fill: Option<Paint>,
     fill_space: Option<Name<'static>>,
-    external_graphics_state: Option<ExternalGraphicsState>,
+    external_graphics_state: Option<ExtGState>,
     stroke: Option<FixedStroke>,
     stroke_space: Option<Name<'static>>,
 }
@@ -287,11 +286,11 @@ impl PageContext<'_, '_> {
         self.state = self.saves.pop().expect("missing state save");
     }
 
-    fn set_external_graphics_state(&mut self, graphics_state: &ExternalGraphicsState) {
+    fn set_external_graphics_state(&mut self, graphics_state: &ExtGState) {
         let current_state = self.state.external_graphics_state.as_ref();
         if current_state != Some(graphics_state) {
-            self.parent.ext_gs_map.insert(*graphics_state);
-            let name = eco_format!("Gs{}", self.parent.ext_gs_map.map(graphics_state));
+            self.parent.extg_map.insert(*graphics_state);
+            let name = eco_format!("Gs{}", self.parent.extg_map.map(graphics_state));
             self.content.set_parameters(Name(name.as_bytes()));
 
             if graphics_state.uses_opacities() {
@@ -321,10 +320,7 @@ impl PageContext<'_, '_> {
                 color.alpha().map_or(255, |v| (v * 255.0).round() as u8)
             })
             .unwrap_or(255);
-        self.set_external_graphics_state(&ExternalGraphicsState {
-            stroke_opacity,
-            fill_opacity,
-        });
+        self.set_external_graphics_state(&ExtGState { stroke_opacity, fill_opacity });
     }
 
     fn transform(&mut self, transform: Transform) {