From 042330cd66dfbeaa4ee31c2d8615af95f01c9d27 Mon Sep 17 00:00:00 2001
From: Tobias Schmitz <tobiasschmitz2001@gmail.com>
Date: Wed, 23 Jul 2025 15:21:35 +0200
Subject: [PATCH] feat: add alt field to figure

---
 crates/typst-layout/src/rules.rs              | 3 ++-
 crates/typst-library/src/model/figure.rs      | 3 +++
 crates/typst-library/src/pdf/accessibility.rs | 7 ++++---
 crates/typst-pdf/src/tags/mod.rs              | 9 ++++++---
 4 files changed, 15 insertions(+), 7 deletions(-)

diff --git a/crates/typst-layout/src/rules.rs b/crates/typst-layout/src/rules.rs
index eb3d10b14..456c73b71 100644
--- a/crates/typst-layout/src/rules.rs
+++ b/crates/typst-layout/src/rules.rs
@@ -282,7 +282,8 @@ const HEADING_RULE: ShowFn<HeadingElem> = |elem, engine, styles| {
 
 const FIGURE_RULE: ShowFn<FigureElem> = |elem, _, styles| {
     let span = elem.span();
-    let mut realized = PdfMarkerTag::FigureBody(elem.body.clone());
+    let mut realized =
+        PdfMarkerTag::FigureBody(elem.alt.get_cloned(styles), elem.body.clone());
 
     // Build the caption, if any.
     if let Some(caption) = elem.caption.get_cloned(styles) {
diff --git a/crates/typst-library/src/model/figure.rs b/crates/typst-library/src/model/figure.rs
index f4b45f897..11d775b69 100644
--- a/crates/typst-library/src/model/figure.rs
+++ b/crates/typst-library/src/model/figure.rs
@@ -103,6 +103,9 @@ use crate::visualize::ImageElem;
 /// ```
 #[elem(scope, Locatable, Synthesize, Count, ShowSet, Refable, Outlinable)]
 pub struct FigureElem {
+    /// An alternative description of the figure.
+    pub alt: Option<EcoString>,
+
     /// The content of the figure. Often, an [image].
     #[required]
     pub body: Content,
diff --git a/crates/typst-library/src/pdf/accessibility.rs b/crates/typst-library/src/pdf/accessibility.rs
index 53ae4d4f0..5705eabe8 100644
--- a/crates/typst-library/src/pdf/accessibility.rs
+++ b/crates/typst-library/src/pdf/accessibility.rs
@@ -1,5 +1,6 @@
 use std::num::NonZeroU32;
 
+use ecow::EcoString;
 use typst_macros::{Cast, elem, func};
 use typst_utils::NonZeroExt;
 
@@ -118,8 +119,8 @@ impl Construct for PdfMarkerTag {
 }
 
 macro_rules! pdf_marker_tag {
-    ($(#[doc = $doc:expr] $variant:ident$(($($name:ident: $ty:ident)+))?,)+) => {
-        #[derive(Debug, Copy, Clone, PartialEq, Eq, Hash)]
+    ($(#[doc = $doc:expr] $variant:ident$(($($name:ident: $ty:ty)+))?,)+) => {
+        #[derive(Debug, Clone, PartialEq, Eq, Hash)]
         pub enum PdfMarkerTagKind {
             $(
                 #[doc = $doc]
@@ -147,7 +148,7 @@ pdf_marker_tag! {
     /// `TOC`
     OutlineBody,
     /// `Figure`
-    FigureBody,
+    FigureBody(alt: Option<EcoString>),
     /// `L` bibliography list
     Bibliography(numbered: bool),
     /// `LBody` wrapping `BibEntry`
diff --git a/crates/typst-pdf/src/tags/mod.rs b/crates/typst-pdf/src/tags/mod.rs
index 0d8df6fb6..a07721048 100644
--- a/crates/typst-pdf/src/tags/mod.rs
+++ b/crates/typst-pdf/src/tags/mod.rs
@@ -59,15 +59,18 @@ pub(crate) fn handle_start(
     }
 
     let mut tag: TagKind = if let Some(tag) = elem.to_packed::<PdfMarkerTag>() {
-        match tag.kind {
+        match &tag.kind {
             PdfMarkerTagKind::OutlineBody => {
                 push_stack(gc, loc, StackEntryKind::Outline(OutlineCtx::new()))?;
                 return Ok(());
             }
-            PdfMarkerTagKind::FigureBody => Tag::Figure(None).into(),
+            PdfMarkerTagKind::FigureBody(alt) => {
+                let alt = alt.as_ref().map(|s| s.to_string());
+                Tag::Figure(alt).into()
+            }
             PdfMarkerTagKind::Bibliography(numbered) => {
                 let numbering =
-                    if numbered { ListNumbering::Decimal } else { ListNumbering::None };
+                    if *numbered { ListNumbering::Decimal } else { ListNumbering::None };
                 push_stack(gc, loc, StackEntryKind::List(ListCtx::new(numbering)))?;
                 return Ok(());
             }