Initial support for breakable figures (#1121)

library/src/meta/figure.rs

@@ -70,9 +70,14 @@ use crate::visualize::ImageElem;
 /// )
 /// ```
 ///
+/// If your figure is too large and its contents are breakable across pages
+/// (e.g. if it contains a large table), then you can make the figure breakable
+/// across pages as well by using `#show figure: set block(breakable: true)`
+/// (see the [block]($func/block) documentation for more information).
+///
 /// Display: Figure
 /// Category: meta
-#[element(Locatable, Synthesize, Count, Show, Refable)]
+#[element(Locatable, Synthesize, Count, Show, Finalize, Refable)]
 pub struct FigureElem {
     /// The content of the figure. Often, an [image]($func/image).
     #[required]
@@ -254,12 +259,18 @@ impl Show for FigureElem {
         // We wrap the contents in a block.
         Ok(BlockElem::new()
             .with_body(Some(realized))
-            .with_breakable(false)
             .pack()
             .aligned(Axes::with_x(Some(Align::Center.into()))))
     }
 }
 
+impl Finalize for FigureElem {
+    fn finalize(&self, realized: Content, _: StyleChain) -> Content {
+        // Allow breakable figures with `show figure: set block(breakable: true)`.
+        realized.styled(BlockElem::set_breakable(false))
+    }
+}
+
 impl Count for FigureElem {
     fn update(&self) -> Option<CounterUpdate> {
         // If the figure is numbered, step the counter by one.

tests/typ/meta/figure.typ

@@ -101,4 +101,11 @@ We can clearly see that @fig-cylinder and
     println!("Hello, world!");
   }
   ```
-]
+]
+
+---
+// Test breakable figures
+#set page(width: 200pt, height: 6em)
+#show figure: set block(breakable: true)
+
+#figure(table[a][b][c][d][e], caption: [A table])