Start & end alignment

src/eval/layout.rs

@@ -5,7 +5,7 @@ use std::fmt::{self, Debug, Formatter};
 use std::hash::Hash;
 use std::sync::Arc;
 
-use super::{Barrier, StyleChain};
+use super::{Barrier, RawAlign, StyleChain};
 use crate::diag::TypResult;
 use crate::frame::{Element, Frame, Geometry, Shape, Stroke};
 use crate::geom::{
@@ -182,7 +182,7 @@ impl LayoutNode {
     }
 
     /// Set alignments for this node.
-    pub fn aligned(self, aligns: Spec<Option<Align>>) -> Self {
+    pub fn aligned(self, aligns: Spec<Option<RawAlign>>) -> Self {
         if aligns.any(Option::is_some) {
             AlignNode { aligns, child: self }.pack()
         } else {

src/eval/mod.rs

@@ -17,6 +17,7 @@ mod func;
 mod layout;
 mod module;
 mod ops;
+mod raw;
 mod scope;
 mod show;
 mod str;
@@ -32,6 +33,7 @@ pub use dict::*;
 pub use func::*;
 pub use layout::*;
 pub use module::*;
+pub use raw::*;
 pub use scope::*;
 pub use show::*;
 pub use styles::*;

src/eval/ops.rs

@@ -1,8 +1,8 @@
 use std::cmp::Ordering;
 
-use super::{Dynamic, StrExt, Value};
+use super::{Dynamic, RawAlign, StrExt, Value};
 use crate::diag::StrResult;
-use crate::geom::{Align, Numeric, Spec, SpecAxis};
+use crate::geom::{Numeric, Spec, SpecAxis};
 use Value::*;
 
 /// Bail with a type mismatch error.
@@ -94,7 +94,7 @@ pub fn add(lhs: Value, rhs: Value) -> StrResult<Value> {
             if let (Dyn(a), Dyn(b)) = (&a, &b) {
                 // 1D alignments can be summed into 2D alignments.
                 if let (Some(&a), Some(&b)) =
-                    (a.downcast::<Align>(), b.downcast::<Align>())
+                    (a.downcast::<RawAlign>(), b.downcast::<RawAlign>())
                 {
                     return if a.axis() != b.axis() {
                         Ok(Dyn(Dynamic::new(match a.axis() {

src/eval/raw.rs

@@ -0,0 +1,49 @@
+use std::fmt::{self, Debug, Formatter};
+
+use super::{Resolve, StyleChain};
+use crate::geom::{Align, SpecAxis};
+use crate::library::text::ParNode;
+
+/// The unresolved alignment representation.
+#[derive(Copy, Clone, Eq, PartialEq, Ord, PartialOrd, Hash)]
+pub enum RawAlign {
+    /// Align at the start side of the text direction.
+    Start,
+    /// Align at the end side of the text direction.
+    End,
+    /// Align at a specific alignment.
+    Specific(Align),
+}
+
+impl Resolve for RawAlign {
+    type Output = Align;
+
+    fn resolve(self, styles: StyleChain) -> Self::Output {
+        let dir = styles.get(ParNode::DIR);
+        match self {
+            Self::Start => dir.start().into(),
+            Self::End => dir.end().into(),
+            Self::Specific(align) => align,
+        }
+    }
+}
+
+impl RawAlign {
+    /// The axis this alignment belongs to.
+    pub const fn axis(self) -> SpecAxis {
+        match self {
+            Self::Start | Self::End => SpecAxis::Horizontal,
+            Self::Specific(align) => align.axis(),
+        }
+    }
+}
+
+impl Debug for RawAlign {
+    fn fmt(&self, f: &mut Formatter) -> fmt::Result {
+        match self {
+            Self::Start => f.pad("left"),
+            Self::End => f.pad("center"),
+            Self::Specific(align) => align.fmt(f),
+        }
+    }
+}

src/frame.rs

@@ -79,8 +79,8 @@ impl Frame {
     pub fn resize(&mut self, target: Size, aligns: Spec<Align>) {
         if self.size != target {
             let offset = Point::new(
-                aligns.x.resolve(target.x - self.size.x),
-                aligns.y.resolve(target.y - self.size.y),
+                aligns.x.position(target.x - self.size.x),
+                aligns.y.position(target.y - self.size.y),
             );
             self.size = target;
             self.translate(offset);

src/geom/align.rs

@@ -45,7 +45,7 @@ impl Align {
     }
 
     /// Returns the position of this alignment in the given length.
-    pub fn resolve(self, length: Length) -> Length {
+    pub fn position(self, length: Length) -> Length {
         match self {
             Self::Left | Self::Top => Length::zero(),
             Self::Center | Self::Horizon => length / 2.0,

src/library/graphics/transform.rs

@@ -22,7 +22,8 @@ pub type ScaleNode = TransformNode<SCALE>;
 #[node]
 impl<const T: TransformKind> TransformNode<T> {
     /// The origin of the transformation.
-    pub const ORIGIN: Spec<Option<Align>> = Spec::default();
+    #[property(resolve)]
+    pub const ORIGIN: Spec<Option<RawAlign>> = Spec::default();
 
     fn construct(_: &mut Context, args: &mut Args) -> TypResult<Content> {
         let transform = match T {
@@ -61,7 +62,7 @@ impl<const T: TransformKind> Layout for TransformNode<T> {
         let mut frames = self.child.layout(ctx, regions, styles)?;
 
         for frame in &mut frames {
-            let Spec { x, y } = origin.zip(frame.size).map(|(o, s)| o.resolve(s));
+            let Spec { x, y } = origin.zip(frame.size).map(|(o, s)| o.position(s));
             let transform = Transform::translate(x, y)
                 .pre_concat(self.transform)
                 .pre_concat(Transform::translate(-x, -y));

src/library/layout/align.rs

@@ -5,7 +5,7 @@ use crate::library::text::ParNode;
 #[derive(Debug, Hash)]
 pub struct AlignNode {
     /// How to align the node horizontally and vertically.
-    pub aligns: Spec<Option<Align>>,
+    pub aligns: Spec<Option<RawAlign>>,
     /// The node to be aligned.
     pub child: LayoutNode,
 }
@@ -42,30 +42,14 @@ impl Layout for AlignNode {
             // Align in the target size. The target size depends on whether we
             // should expand.
             let target = regions.expand.select(region, frame.size);
-            let default = Spec::new(Align::Left, Align::Top);
-            let aligns = self.aligns.unwrap_or(default);
+            let aligns = self
+                .aligns
+                .map(|align| align.resolve(styles))
+                .unwrap_or(Spec::new(Align::Left, Align::Top));
+
             Arc::make_mut(frame).resize(target, aligns);
         }
 
         Ok(frames)
     }
 }
-
-dynamic! {
-    Align: "alignment",
-}
-
-dynamic! {
-    Spec<Align>: "2d alignment",
-}
-
-castable! {
-    Spec<Option<Align>>,
-    Expected: "1d or 2d alignment",
-    @align: Align => {
-        let mut aligns = Spec::default();
-        aligns.set(align.axis(), Some(*align));
-        aligns
-    },
-    @aligns: Spec<Align> => aligns.map(Some),
-}

src/library/layout/flow.rs

@@ -189,6 +189,7 @@ impl FlowLayouter {
             // Vertical align node alignment is respected by the flow node.
             node.downcast::<AlignNode>()
                 .and_then(|aligned| aligned.aligns.y)
+                .map(|align| align.resolve(styles))
                 .unwrap_or(Align::Top),
         );
 
@@ -238,8 +239,8 @@ impl FlowLayouter {
                 }
                 FlowItem::Frame(frame, aligns) => {
                     ruler = ruler.max(aligns.y);
-                    let x = aligns.x.resolve(size.x - frame.size.x);
-                    let y = offset + ruler.resolve(size.y - self.used.y);
+                    let x = aligns.x.position(size.x - frame.size.x);
+                    let y = offset + ruler.position(size.y - self.used.y);
                     let pos = Point::new(x, y);
                     offset += frame.size.y;
                     output.push_frame(pos, frame);

src/library/layout/place.rs

@@ -8,9 +8,9 @@ pub struct PlaceNode(pub LayoutNode);
 #[node]
 impl PlaceNode {
     fn construct(_: &mut Context, args: &mut Args) -> TypResult<Content> {
-        let aligns = args.find()?.unwrap_or(Spec::with_x(Some(Align::Left)));
         let tx = args.named("dx")?.unwrap_or_default();
         let ty = args.named("dy")?.unwrap_or_default();
+        let aligns = args.find()?.unwrap_or(Spec::with_x(Some(RawAlign::Start)));
         let body: LayoutNode = args.expect("body")?;
         Ok(Content::block(Self(
             body.moved(Point::new(tx, ty)).aligned(aligns),

src/library/layout/stack.rs

@@ -175,6 +175,7 @@ impl StackLayouter {
         let align = node
             .downcast::<AlignNode>()
             .and_then(|node| node.aligns.get(self.axis))
+            .map(|align| align.resolve(styles))
             .unwrap_or(self.dir.start().into());
 
         let frames = node.layout(ctx, &self.regions, styles)?;
@@ -229,7 +230,7 @@ impl StackLayouter {
                     // Align along the block axis.
                     let parent = size.get(self.axis);
                     let child = frame.size.get(self.axis);
-                    let block = ruler.resolve(parent - self.used.main)
+                    let block = ruler.position(parent - self.used.main)
                         + if self.dir.is_positive() {
                             cursor
                         } else {

src/library/mod.rs

@@ -113,12 +113,14 @@ pub fn new() -> Scope {
     std.def_const("rtl", Dir::RTL);
     std.def_const("ttb", Dir::TTB);
     std.def_const("btt", Dir::BTT);
-    std.def_const("left", Align::Left);
-    std.def_const("center", Align::Center);
-    std.def_const("right", Align::Right);
-    std.def_const("top", Align::Top);
-    std.def_const("horizon", Align::Horizon);
-    std.def_const("bottom", Align::Bottom);
+    std.def_const("start", RawAlign::Start);
+    std.def_const("end", RawAlign::End);
+    std.def_const("left", RawAlign::Specific(Align::Left));
+    std.def_const("center", RawAlign::Specific(Align::Center));
+    std.def_const("right", RawAlign::Specific(Align::Right));
+    std.def_const("top", RawAlign::Specific(Align::Top));
+    std.def_const("horizon", RawAlign::Specific(Align::Horizon));
+    std.def_const("bottom", RawAlign::Specific(Align::Bottom));
 
     std
 }
@@ -127,6 +129,25 @@ dynamic! {
     Dir: "direction",
 }
 
+dynamic! {
+    RawAlign: "alignment",
+}
+
+dynamic! {
+    Spec<RawAlign>: "2d alignment",
+}
+
+castable! {
+    Spec<Option<RawAlign>>,
+    Expected: "1d or 2d alignment",
+    @align: RawAlign => {
+        let mut aligns = Spec::default();
+        aligns.set(align.axis(), Some(*align));
+        aligns
+    },
+    @aligns: Spec<RawAlign> => aligns.map(Some),
+}
+
 castable! {
     usize,
     Expected: "non-negative integer",

src/library/prelude.rs

@@ -10,7 +10,8 @@ pub use typst_macros::node;
 pub use crate::diag::{with_alternative, At, Error, StrResult, TypError, TypResult};
 pub use crate::eval::{
     Arg, Args, Array, Cast, Content, Dict, Fold, Func, Key, Layout, LayoutNode, Merge,
-    Node, Regions, Scope, Show, ShowNode, Smart, StyleChain, StyleMap, StyleVec, Value,
+    Node, RawAlign, Regions, Resolve, Scope, Show, ShowNode, Smart, StyleChain, StyleMap,
+    StyleVec, Value,
 };
 pub use crate::frame::*;
 pub use crate::geom::*;

src/library/text/par.rs

@@ -33,7 +33,8 @@ impl ParNode {
     /// The direction for text and inline objects.
     pub const DIR: Dir = Dir::LTR;
     /// How to align text and inline objects in their line.
-    pub const ALIGN: Align = Align::Left;
+    #[property(resolve)]
+    pub const ALIGN: RawAlign = RawAlign::Start;
     /// Whether to justify text in its line.
     pub const JUSTIFY: bool = false;
     /// How to determine line breaks.
@@ -74,15 +75,13 @@ impl ParNode {
             dir = Some(v);
         }
 
-        let align =
-            if let Some(Spanned { v, span }) = args.named::<Spanned<Align>>("align")? {
-                if v.axis() != SpecAxis::Horizontal {
-                    bail!(span, "must be horizontal");
-                }
-                Some(v)
-            } else {
-                dir.map(|dir| dir.start().into())
-            };
+        let mut align = None;
+        if let Some(Spanned { v, span }) = args.named::<Spanned<RawAlign>>("align")? {
+            if v.axis() != SpecAxis::Horizontal {
+                bail!(span, "must be horizontal");
+            }
+            align = Some(v);
+        };
 
         styles.set_opt(Self::LANG, lang);
         styles.set_opt(Self::DIR, dir);
@@ -880,7 +879,7 @@ fn commit(
     // Construct the line's frame from left to right.
     for item in reordered {
         let mut position = |frame: Frame| {
-            let x = offset + align.resolve(remaining);
+            let x = offset + align.position(remaining);
             let y = line.baseline - frame.baseline();
             offset += frame.size.x;
             output.merge_frame(Point::new(x, y), frame);

tests/typ/layout/align.typ

@@ -14,12 +14,25 @@
 ))
 
 ---
+// Test that multiple paragraphs in subflow also respect alignment.
 #align(center)[
   Lorem Ipsum
 
   Dolor
 ]
 
+---
+// Test start and end alignment.
+#rotate(-30deg, origin: end + horizon)[Hello]
+
+#set par(lang: "de")
+#align(start)[Start]
+#align(end)[Ende]
+
+#set par(lang: "ar")
+#align(start)[يبدأ]
+#align(end)[نهاية]
+
 ---
 // Ref: false
 #test(type(center), "alignment")