Levels

4 files changed, 37 insertions, 9 deletions

diff --git a/src/layout/incremental.rs b/src/layout/incremental.rs
index 427df079..7857f33c 100644
--- a/src/layout/incremental.rs
+++ b/src/layout/incremental.rs
@@ -20,6 +20,19 @@ impl LayoutCache {
     pub fn clear(&mut self) {
         self.frames.clear();
     }
+
+    /// Retains all elements for which the closure on the level returns `true`.
+    pub fn retain<F>(&mut self, mut f: F)
+    where
+        F: FnMut(usize) -> bool,
+    {
+        self.frames.retain(|_, b| f(b.level));
+    }
+
+    /// Amount of items in the cache.
+    pub fn len(&self) -> usize {
+        self.frames.len()
+    }
 }
 
 #[derive(Debug, Clone)]
@@ -27,6 +40,8 @@ impl LayoutCache {
 pub struct FramesEntry {
     /// The cached frames for a node.
     pub frames: Vec<Constrained<Frame>>,
+    /// How nested the frame was in the context is was originally appearing in.
+    pub level: usize,
 }
 
 impl FramesEntry {
diff --git a/src/layout/mod.rs b/src/layout/mod.rs
index 15c80017..28e83da9 100644
--- a/src/layout/mod.rs
+++ b/src/layout/mod.rs
@@ -32,7 +32,7 @@ use crate::loading::Loader;
 
 /// Layout a tree into a collection of frames.
 pub fn layout(loader: &mut dyn Loader, cache: &mut Cache, tree: &Tree) -> Vec<Frame> {
-    tree.layout(&mut LayoutContext { loader, cache })
+    tree.layout(&mut LayoutContext { loader, cache, level: 0 })
 }
 
 /// A tree of layout nodes.
@@ -98,19 +98,23 @@ impl Layout for AnyNode {
         ctx: &mut LayoutContext,
         regions: &Regions,
     ) -> Vec<Constrained<Frame>> {
-        ctx.cache
+        ctx.level += 1;
+        let frames = ctx
+            .cache
             .layout
             .frames
             .get(&self.hash)
             .and_then(|x| x.check(regions.clone()))
             .unwrap_or_else(|| {
                 let frames = self.node.layout(ctx, regions);
-                ctx.cache
-                    .layout
-                    .frames
-                    .insert(self.hash, FramesEntry { frames: frames.clone() });
+                ctx.cache.layout.frames.insert(self.hash, FramesEntry {
+                    frames: frames.clone(),
+                    level: ctx.level - 1,
+                });
                 frames
-            })
+            });
+        ctx.level -= 1;
+        frames
     }
 }
 
@@ -184,6 +188,8 @@ pub struct LayoutContext<'a> {
     pub loader: &'a mut dyn Loader,
     /// A cache for loaded fonts and artifacts from past layouting.
     pub cache: &'a mut Cache,
+    /// How deeply nested is the current layout tree position.
+    pub level: usize,
 }
 
 /// A sequence of regions to layout into.
diff --git a/src/library/image.rs b/src/library/image.rs
index bd7f2f67..f8c04cbe 100644
--- a/src/library/image.rs
+++ b/src/library/image.rs
@@ -2,7 +2,9 @@ use ::image::GenericImageView;
 
 use super::*;
 use crate::image::ImageId;
-use crate::layout::{AnyNode, Constrained, Constraints, Element, Frame, Layout, LayoutContext, Regions};
+use crate::layout::{
+    AnyNode, Constrained, Constraints, Element, Frame, Layout, LayoutContext, Regions,
+};
 
 /// `image`: An image.
 ///
@@ -52,7 +54,11 @@ struct ImageNode {
 }
 
 impl Layout for ImageNode {
-    fn layout(&self, _: &mut LayoutContext, regions: &Regions) -> Vec<Constrained<Frame>> {
+    fn layout(
+        &self,
+        _: &mut LayoutContext,
+        regions: &Regions,
+    ) -> Vec<Constrained<Frame>> {
         let Regions { current, base, .. } = regions;
         let mut constraints = Constraints::new(regions.expand);
         constraints.set_base_using_linears(Spec::new(self.width, self.height), regions);
diff --git a/tests/typeset.rs b/tests/typeset.rs
index f4e74bc1..c6d3e8f1 100644
--- a/tests/typeset.rs
+++ b/tests/typeset.rs
@@ -225,6 +225,7 @@ fn test_part(
     state.page.margins = Sides::splat(Some(Length::pt(10.0).into()));
 
     let mut pass = typst::typeset(loader, cache, Some(src_path), &src, &scope, state);
+
     if !compare_ref {
         pass.output.clear();
     }