test: snapshot testing of pdf tag trees

Cargo.lock

@@ -1430,7 +1430,7 @@ dependencies = [
 [[package]]
 name = "krilla"
 version = "0.4.0"
-source = "git+https://github.com/LaurenzV/krilla?branch=main#9bfd3adc167080017c6e90a5447b83b376c881ff"
+source = "git+https://github.com/LaurenzV/krilla?branch=main#576fb4f95d975ce366f18ad552a62286f6fbd0ec"
 dependencies = [
  "base64",
  "bumpalo",
@@ -1460,7 +1460,7 @@ dependencies = [
 [[package]]
 name = "krilla-svg"
 version = "0.1.0"
-source = "git+https://github.com/LaurenzV/krilla?branch=main#9bfd3adc167080017c6e90a5447b83b376c881ff"
+source = "git+https://github.com/LaurenzV/krilla?branch=main#576fb4f95d975ce366f18ad552a62286f6fbd0ec"
 dependencies = [
  "flate2",
  "fontdb",
@@ -3306,6 +3306,7 @@ dependencies = [
  "clap",
  "comemo",
  "ecow",
+ "krilla",
  "oxipng",
  "parking_lot",
  "rayon",

crates/typst-pdf/src/convert.rs

@@ -9,7 +9,7 @@ use krilla::geom::PathBuilder;
 use krilla::page::{PageLabel, PageSettings};
 use krilla::pdf::PdfError;
 use krilla::surface::Surface;
-use krilla::tagging::TagId;
+use krilla::tagging::{TagId, TagTree};
 use krilla::{Document, SerializeSettings};
 use krilla_svg::render_svg_glyph;
 use typst_library::diag::{SourceDiagnostic, SourceResult, bail, error};
@@ -40,6 +40,31 @@ pub fn convert(
     typst_document: &PagedDocument,
     options: &PdfOptions,
 ) -> SourceResult<Vec<u8>> {
+    let (mut document, mut gc) = setup(typst_document, options);
+
+    convert_pages(&mut gc, &mut document)?;
+    embed_files(typst_document, &mut document)?;
+
+    document.set_outline(build_outline(&gc));
+    document.set_metadata(build_metadata(&gc));
+    document.set_tag_tree(gc.tags.build_tree());
+
+    finish(document, gc, options.standards.config)
+}
+
+pub fn tag_tree(
+    typst_document: &PagedDocument,
+    options: &PdfOptions,
+) -> SourceResult<TagTree> {
+    let (mut document, mut gc) = setup(typst_document, options);
+    convert_pages(&mut gc, &mut document)?;
+    Ok(gc.tags.build_tree())
+}
+
+fn setup<'a>(
+    typst_document: &'a PagedDocument,
+    options: &'a PdfOptions,
+) -> (Document, GlobalContext<'a>) {
     let settings = SerializeSettings {
         compress_content_streams: true,
         no_device_cs: true,
@@ -51,26 +76,19 @@ pub fn convert(
         render_svg_glyph_fn: render_svg_glyph,
     };
 
-    let mut document = Document::new_with(settings);
+    let document = Document::new_with(settings);
     let page_index_converter = PageIndexConverter::new(typst_document, options);
     let named_destinations =
         collect_named_destinations(typst_document, &page_index_converter);
 
-    let mut gc = GlobalContext::new(
+    let gc = GlobalContext::new(
         typst_document,
         options,
         named_destinations,
         page_index_converter,
     );
 
-    convert_pages(&mut gc, &mut document)?;
-    embed_files(typst_document, &mut document)?;
-
-    document.set_outline(build_outline(&gc));
-    document.set_metadata(build_metadata(&gc));
-    document.set_tag_tree(gc.tags.build_tree());
-
-    finish(document, gc, options.standards.config)
+    (document, gc)
 }
 
 fn convert_pages(gc: &mut GlobalContext, document: &mut Document) -> SourceResult<()> {

crates/typst-pdf/src/lib.rs

@@ -18,6 +18,7 @@ pub use self::metadata::{Timestamp, Timezone};
 use std::fmt::{self, Debug, Formatter};
 
 use ecow::eco_format;
+use krilla::tagging::TagTree;
 use serde::{Deserialize, Serialize};
 use typst_library::diag::{SourceResult, StrResult, bail};
 use typst_library::foundations::Smart;
@@ -31,6 +32,12 @@ pub fn pdf(document: &PagedDocument, options: &PdfOptions) -> SourceResult<Vec<u
     convert::convert(document, options)
 }
 
+/// Generate the document tag tree and display it in a human readable form.
+#[doc(hidden)]
+pub fn pdf_tags(document: &PagedDocument, options: &PdfOptions) -> SourceResult<TagTree> {
+    convert::tag_tree(document, options)
+}
+
 /// Settings for PDF export.
 #[derive(Debug, Default)]
 pub struct PdfOptions<'a> {

tests/Cargo.toml

@@ -25,6 +25,7 @@ default = [
     "typst-render",
     "typst-svg",
     "typst-svg",
+    "krilla",
 ]
 
 [dependencies]
@@ -39,6 +40,7 @@ typst-library = { workspace = true, optional = true }
 typst-pdf = { workspace = true, optional = true }
 typst-render = { workspace = true, optional = true }
 typst-svg = { workspace = true, optional = true }
+krilla = { workspace = true, optional = true }
 clap = { workspace = true }
 comemo = { workspace = true }
 ecow = { workspace = true }

tests/src/collect.rs

@@ -66,6 +66,7 @@ pub enum Attr {
     Html,
     Render,
     Large,
+    Pdftags,
 }
 
 /// The size of a file.
@@ -304,6 +305,7 @@ impl<'a> Parser<'a> {
                 "large" => Attr::Large,
                 "html" => Attr::Html,
                 "render" => Attr::Render,
+                "pdftags" => Attr::Pdftags,
                 found => {
                     self.error(format!(
                         "expected attribute or closing ---, found `{found}`"

tests/src/run.rs

@@ -3,13 +3,15 @@ use std::ops::Range;
 use std::path::PathBuf;
 
 use ecow::eco_vec;
+use krilla::tagging::TagTree;
+use krilla::tagging::fmt::Output;
 use tiny_skia as sk;
 use typst::diag::{SourceDiagnostic, SourceResult, Warned};
 use typst::layout::{Abs, Frame, FrameItem, PagedDocument, Transform};
 use typst::visualize::Color;
-use typst::{Document, WorldExt};
+use typst::{World, WorldExt};
 use typst_html::HtmlDocument;
-use typst_pdf::PdfOptions;
+use typst_pdf::{PdfOptions, PdfStandard, PdfStandards};
 use typst_syntax::{FileId, Lines};
 
 use crate::collect::{Attr, FileSize, NoteKind, Test};
@@ -65,13 +67,17 @@ impl<'a> Runner<'a> {
         }
 
         let html = self.test.attrs.contains(&Attr::Html);
-        let render = !html || self.test.attrs.contains(&Attr::Render);
+        let pdftags = self.test.attrs.contains(&Attr::Pdftags);
+        let render = !html && !pdftags || self.test.attrs.contains(&Attr::Render);
         if render {
             self.run_test::<PagedDocument>();
         }
         if html {
             self.run_test::<HtmlDocument>();
         }
+        if pdftags {
+            self.run_test::<TagTree>();
+        }
 
         self.handle_not_emitted();
         self.handle_not_annotated();
@@ -81,7 +87,7 @@ impl<'a> Runner<'a> {
 
     /// Run test specific to document format.
     fn run_test<D: OutputType>(&mut self) {
-        let Warned { output, warnings } = typst::compile(&self.world);
+        let Warned { output, warnings } = D::compile(&self.world);
         let (doc, mut errors) = match output {
             Ok(doc) => (Some(doc), eco_vec![]),
             Err(errors) => (None, errors),
@@ -89,7 +95,7 @@ impl<'a> Runner<'a> {
 
         D::check_custom(self, doc.as_ref());
 
-        let output = doc.and_then(|doc: D| match doc.make_live() {
+        let output = doc.and_then(|doc| match doc.make_live() {
             Ok(live) => Some((doc, live)),
             Err(list) => {
                 errors.extend(list);
@@ -357,13 +363,15 @@ impl<'a> Runner<'a> {
 }
 
 /// An output type we can test.
-trait OutputType: Document {
+trait OutputType: Sized {
     /// The type that represents live output.
     type Live;
 
     /// The path at which the live output is stored.
     fn live_path(name: &str) -> PathBuf;
 
+    fn compile(world: &dyn World) -> Warned<SourceResult<Self>>;
+
     /// The path at which the reference output is stored.
     fn ref_path(name: &str) -> PathBuf;
 
@@ -400,6 +408,10 @@ impl OutputType for PagedDocument {
         format!("{}/{}.png", crate::REF_PATH, name).into()
     }
 
+    fn compile(world: &dyn World) -> Warned<SourceResult<Self>> {
+        typst::compile(world)
+    }
+
     fn is_skippable(&self) -> Result<bool, ()> {
         /// Whether rendering of a frame can be skipped.
         fn skippable_frame(frame: &Frame) -> bool {
@@ -485,6 +497,10 @@ impl OutputType for HtmlDocument {
         format!("{}/html/{}.html", crate::REF_PATH, name).into()
     }
 
+    fn compile(world: &dyn World) -> Warned<SourceResult<Self>> {
+        typst::compile(world)
+    }
+
     fn make_live(&self) -> SourceResult<Self::Live> {
         typst_html::html(self)
     }
@@ -502,6 +518,50 @@ impl OutputType for HtmlDocument {
     }
 }
 
+impl OutputType for TagTree {
+    type Live = String;
+
+    fn live_path(name: &str) -> PathBuf {
+        format!("{}/pdftags/{}.yml", crate::STORE_PATH, name).into()
+    }
+
+    fn ref_path(name: &str) -> PathBuf {
+        format!("{}/pdftags/{}.yml", crate::REF_PATH, name).into()
+    }
+
+    fn compile(world: &dyn World) -> Warned<SourceResult<Self>> {
+        let Warned { output, warnings } = typst::compile::<PagedDocument>(world);
+        let doc = match output {
+            Ok(doc) => doc,
+            Err(errors) => return Warned { output: Err(errors), warnings },
+        };
+        let mut options = PdfOptions::default();
+        options.standards = PdfStandards::new(&[PdfStandard::Ua_1]).unwrap();
+        let output = typst_pdf::pdf_tags(&doc, &options);
+        Warned { warnings, output }
+    }
+
+    fn is_skippable(&self) -> Result<bool, ()> {
+        Ok(self.children.is_empty())
+    }
+
+    fn make_live(&self) -> SourceResult<Self::Live> {
+        Ok(self.display().to_string())
+    }
+
+    fn save_live(&self, name: &str, live: &Self::Live) {
+        std::fs::write(Self::live_path(name), live).unwrap();
+    }
+
+    fn make_ref(live: Self::Live) -> Vec<u8> {
+        live.into_bytes()
+    }
+
+    fn matches(live: &Self::Live, ref_data: &[u8]) -> bool {
+        live.as_bytes() == ref_data
+    }
+}
+
 /// Draw all frames into one image with padding in between.
 fn render(document: &PagedDocument, pixel_per_pt: f32) -> sk::Pixmap {
     for page in &document.pages {

tests/src/tests.rs

@@ -64,7 +64,7 @@ fn setup() {
     std::env::set_current_dir(workspace_dir).unwrap();
 
     // Create the storage.
-    for ext in ["render", "html", "pdf", "svg"] {
+    for ext in ["render", "html", "pdf", "pdftags", "svg"] {
         std::fs::create_dir_all(Path::new(STORE_PATH).join(ext)).unwrap();
     }