Align set rule

9 files changed, 36 insertions, 94 deletions

diff --git a/library/src/layout/align.rs b/library/src/layout/align.rs
index ae60b4c6..506ef684 100644
--- a/library/src/layout/align.rs
+++ b/library/src/layout/align.rs
@@ -1,62 +1,22 @@
-use super::{HorizontalAlign, ParNode};
 use crate::prelude::*;
 
-/// Align content along the layouting axes.
+/// Just an empty shell to scope styles.
 #[derive(Debug, Hash)]
-pub struct AlignNode {
-    /// How to align the content horizontally and vertically.
-    pub aligns: Axes<Option<GenAlign>>,
-    /// The content to be aligned.
-    pub body: Content,
-}
+pub enum AlignNode {}
 
-#[node(Layout)]
+#[node]
 impl AlignNode {
-    fn construct(_: &Vm, args: &mut Args) -> SourceResult<Content> {
-        let aligns: Axes<Option<GenAlign>> = args.find()?.unwrap_or_default();
-        let body: Content = args.expect("body")?;
+    /// The alignment.
+    #[property(fold, skip)]
+    pub const ALIGNS: Axes<Option<GenAlign>> =
+        Axes::new(GenAlign::Start, GenAlign::Specific(Align::Top));
 
-        if let Axes { x: Some(x), y: None } = aligns {
-            if !body.has::<dyn Layout>() || body.has::<dyn Inline>() {
-                return Ok(body.styled(ParNode::ALIGN, HorizontalAlign(x)));
-            }
-        }
-
-        Ok(Self { aligns, body }.pack())
+    fn construct(_: &Vm, args: &mut Args) -> SourceResult<Content> {
+        args.expect("body")
     }
-}
 
-impl Layout for AlignNode {
-    fn layout(
-        &self,
-        vt: &mut Vt,
-        styles: StyleChain,
-        regions: Regions,
-    ) -> SourceResult<Fragment> {
-        // The child only needs to expand along an axis if there's no alignment.
-        let mut pod = regions.clone();
-        pod.expand &= self.aligns.as_ref().map(Option::is_none);
-
-        // Align paragraphs inside the child.
-        let mut map = StyleMap::new();
-        if let Some(align) = self.aligns.x {
-            map.set(ParNode::ALIGN, HorizontalAlign(align));
-        }
-
-        // Layout the child.
-        let mut fragment = self.body.layout(vt, styles.chain(&map), pod)?;
-        for (region, frame) in regions.iter().zip(&mut fragment) {
-            // Align in the target size. The target size depends on whether we
-            // should expand.
-            let target = regions.expand.select(region, frame.size());
-            let aligns = self
-                .aligns
-                .map(|align| align.resolve(styles))
-                .unwrap_or(Axes::new(Align::Left, Align::Top));
-
-            frame.resize(target, aligns);
-        }
-
-        Ok(fragment)
+    fn set(...) {
+        let aligns: Axes<Option<GenAlign>> = args.find()?.unwrap_or_default();
+        styles.set(Self::ALIGNS, aligns);
     }
 }
diff --git a/library/src/layout/flow.rs b/library/src/layout/flow.rs
index 0b6454a0..b78f3932 100644
--- a/library/src/layout/flow.rs
+++ b/library/src/layout/flow.rs
@@ -125,7 +125,7 @@ impl<'a> FlowLayouter<'a> {
         par: &ParNode,
         styles: StyleChain,
     ) -> SourceResult<()> {
-        let aligns = Axes::new(styles.get(ParNode::ALIGN), Align::Top);
+        let aligns = styles.get(AlignNode::ALIGNS).resolve(styles);
         let leading = styles.get(ParNode::LEADING);
         let consecutive = self.last_was_par;
         let fragment = par.layout(
@@ -172,17 +172,7 @@ impl<'a> FlowLayouter<'a> {
         }
 
         // How to align the block.
-        let aligns = Axes::new(
-            // For non-expanding paragraphs it is crucial that we align the
-            // whole paragraph as it is itself aligned.
-            styles.get(ParNode::ALIGN),
-            // Vertical align node alignment is respected by the flow.
-            block
-                .to::<AlignNode>()
-                .and_then(|aligned| aligned.aligns.y)
-                .map(|align| align.resolve(styles))
-                .unwrap_or(Align::Top),
-        );
+        let aligns = styles.get(AlignNode::ALIGNS).resolve(styles);
 
         // Layout the block itself.
         let sticky = styles.get(BlockNode::STICKY);
diff --git a/library/src/layout/mod.rs b/library/src/layout/mod.rs
index 00b1f9be..afa1344f 100644
--- a/library/src/layout/mod.rs
+++ b/library/src/layout/mod.rs
@@ -412,7 +412,9 @@ impl<'a, 'v, 't> Builder<'a, 'v, 't> {
                 bail!(span, "not allowed here");
             }
             self.interrupt_page(styles)?;
-        } else if map.interruption::<ParNode>().is_some() {
+        } else if map.interruption::<ParNode>().is_some()
+            || map.interruption::<AlignNode>().is_some()
+        {
             self.interrupt_par()?;
         } else if map.interruption::<ListNode>().is_some()
             || map.interruption::<EnumNode>().is_some()
diff --git a/library/src/layout/par.rs b/library/src/layout/par.rs
index c0e7c6c9..d93bfba7 100644
--- a/library/src/layout/par.rs
+++ b/library/src/layout/par.rs
@@ -5,6 +5,7 @@ use xi_unicode::LineBreakIterator;
 use typst::model::Key;
 
 use super::{HNode, RepeatNode, Spacing};
+use crate::layout::AlignNode;
 use crate::prelude::*;
 use crate::text::{
     shape, LinebreakNode, Quoter, Quotes, ShapedText, SmartQuoteNode, SpaceNode, TextNode,
@@ -22,9 +23,6 @@ impl ParNode {
     /// The spacing between lines.
     #[property(resolve)]
     pub const LEADING: Length = Em::new(0.65).into();
-    /// How to align text and inline objects in their line.
-    #[property(resolve)]
-    pub const ALIGN: HorizontalAlign = HorizontalAlign(GenAlign::Start);
     /// Whether to justify text in its line.
     pub const JUSTIFY: bool = false;
     /// How to determine line breaks.
@@ -554,7 +552,7 @@ fn prepare<'a>(
         styles,
         hyphenate: shared_get(styles, &par.0, TextNode::HYPHENATE),
         lang: shared_get(styles, &par.0, TextNode::LANG),
-        align: styles.get(ParNode::ALIGN),
+        align: styles.get(AlignNode::ALIGNS).x.resolve(styles),
         justify: styles.get(ParNode::JUSTIFY),
     })
 }
diff --git a/library/src/layout/place.rs b/library/src/layout/place.rs
index 2e2c81a1..28d231b7 100644
--- a/library/src/layout/place.rs
+++ b/library/src/layout/place.rs
@@ -1,9 +1,8 @@
-use super::AlignNode;
 use crate::prelude::*;
 
 /// Place content at an absolute position.
 #[derive(Debug, Hash)]
-pub struct PlaceNode(pub Content);
+pub struct PlaceNode(pub Content, bool);
 
 #[node(Layout, Behave)]
 impl PlaceNode {
@@ -12,7 +11,8 @@ impl PlaceNode {
         let dx = args.named("dx")?.unwrap_or_default();
         let dy = args.named("dy")?.unwrap_or_default();
         let body = args.expect::<Content>("body")?;
-        Ok(Self(body.moved(Axes::new(dx, dy)).aligned(aligns)).pack())
+        let out_of_flow = aligns.y.is_some();
+        Ok(Self(body.moved(Axes::new(dx, dy)).aligned(aligns), out_of_flow).pack())
     }
 }
 
@@ -49,7 +49,7 @@ impl PlaceNode {
     /// origin. Instead of relative to the parent's current flow/cursor
     /// position.
     pub fn out_of_flow(&self) -> bool {
-        self.0.to::<AlignNode>().map_or(false, |node| node.aligns.y.is_some())
+        self.1
     }
 }
 
diff --git a/library/src/layout/stack.rs b/library/src/layout/stack.rs
index 6432f4ac..d44dcb48 100644
--- a/library/src/layout/stack.rs
+++ b/library/src/layout/stack.rs
@@ -1,6 +1,6 @@
 use typst::model::StyledNode;
 
-use super::{AlignNode, ParNode, Spacing};
+use super::{AlignNode, Spacing};
 use crate::prelude::*;
 
 /// Arrange content and spacing along an axis.
@@ -180,21 +180,13 @@ impl<'a> StackLayouter<'a> {
 
         // Block-axis alignment of the `AlignNode` is respected
         // by the stack node.
-        let align = block
-            .to::<AlignNode>()
-            .and_then(|node| node.aligns.get(self.axis))
-            .map(|align| align.resolve(styles))
-            .unwrap_or_else(|| {
-                if let Some(styled) = block.to::<StyledNode>() {
-                    let map = &styled.map;
-                    if map.contains(ParNode::ALIGN) {
-                        return StyleChain::new(map).get(ParNode::ALIGN);
-                    }
-                }
-
-                self.dir.start().into()
-            });
+        let aligns = if let Some(styled) = block.to::<StyledNode>() {
+            styles.chain(&styled.map).get(AlignNode::ALIGNS)
+        } else {
+            styles.get(AlignNode::ALIGNS)
+        };
 
+        let align = aligns.get(self.axis).resolve(styles);
         let fragment = block.layout(vt, styles, self.regions)?;
         let len = fragment.len();
         for (i, frame) in fragment.into_iter().enumerate() {
diff --git a/library/src/lib.rs b/library/src/lib.rs
index e41e7c0d..86bef0b9 100644
--- a/library/src/lib.rs
+++ b/library/src/lib.rs
@@ -208,6 +208,6 @@ fn items() -> LangItems {
         math_atom: |atom| math::AtomNode(atom).pack(),
         math_script: |base, sub, sup| math::ScriptNode { base, sub, sup }.pack(),
         math_frac: |num, denom| math::FracNode { num, denom }.pack(),
-        math_align: |count| math::AlignNode(count).pack(),
+        math_align_point: |count| math::AlignPointNode(count).pack(),
     }
 }
diff --git a/library/src/math/mod.rs b/library/src/math/mod.rs
index 1139296c..62432b12 100644
--- a/library/src/math/mod.rs
+++ b/library/src/math/mod.rs
@@ -442,14 +442,14 @@ impl Texify for ScriptNode {
     }
 }
 
-/// A math alignment indicator: `&`, `&&`.
+/// A math alignment point: `&`, `&&`.
 #[derive(Debug, Hash)]
-pub struct AlignNode(pub usize);
+pub struct AlignPointNode(pub usize);
 
 #[node(Texify)]
-impl AlignNode {}
+impl AlignPointNode {}
 
-impl Texify for AlignNode {
+impl Texify for AlignPointNode {
     fn texify(&self, _: &mut Texifier) -> SourceResult<()> {
         Ok(())
     }
diff --git a/library/src/shared/ext.rs b/library/src/shared/ext.rs
index 811ae757..23db71f9 100644
--- a/library/src/shared/ext.rs
+++ b/library/src/shared/ext.rs
@@ -57,7 +57,7 @@ impl ContentExt for Content {
     }
 
     fn aligned(self, aligns: Axes<Option<GenAlign>>) -> Self {
-        crate::layout::AlignNode { aligns, body: self }.pack()
+        self.styled(crate::layout::AlignNode::ALIGNS, aligns)
     }
 
     fn padded(self, padding: Sides<Rel<Length>>) -> Self {