From 89f2e71852e96062ea9b756bf92fbf4e894871b1 Mon Sep 17 00:00:00 2001
From: Laurenz <laurmaedje@gmail.com>
Date: Wed, 17 Nov 2021 17:09:19 +0100
Subject: Align node

---
 src/library/align.rs | 106 ++++++++++++++++++++++++++++++++-------------------
 src/library/flow.rs  |  69 +++++++++++++++++++--------------
 src/library/image.rs |   4 +-
 src/library/mod.rs   |   6 +--
 src/library/par.rs   |  56 +++++++++++++--------------
 src/library/shape.rs |  14 ++++++-
 src/library/sized.rs |   2 +-
 src/library/stack.rs |  36 +++++++++++------
 8 files changed, 176 insertions(+), 117 deletions(-)

(limited to 'src/library')

diff --git a/src/library/align.rs b/src/library/align.rs
index c6f96a13..591a4085 100644
--- a/src/library/align.rs
+++ b/src/library/align.rs
@@ -1,51 +1,77 @@
 use super::prelude::*;
 
 /// `align`: Configure the alignment along the layouting axes.
-pub fn align(ctx: &mut EvalContext, args: &mut Args) -> TypResult<Value> {
-    let first = args.find::<Align>();
-    let second = args.find::<Align>();
-    let body = args.find::<Template>();
-
-    let mut horizontal = args.named("horizontal")?;
-    let mut vertical = args.named("vertical")?;
-
-    for value in first.into_iter().chain(second) {
-        match value.axis() {
-            Some(SpecAxis::Horizontal) | None if horizontal.is_none() => {
-                horizontal = Some(value);
-            }
-            Some(SpecAxis::Vertical) | None if vertical.is_none() => {
-                vertical = Some(value);
-            }
-            _ => {}
+pub fn align(_: &mut EvalContext, args: &mut Args) -> TypResult<Value> {
+    let mut x = args.named("horizontal")?;
+    let mut y = args.named("vertical")?;
+    for Spanned { v, span } in args.all::<Spanned<Align>>() {
+        match v.axis() {
+            None | Some(SpecAxis::Horizontal) if x.is_none() => x = Some(v),
+            None | Some(SpecAxis::Vertical) if y.is_none() => y = Some(v),
+            _ => bail!(span, "unexpected argument"),
         }
     }
 
-    let realign = |template: &mut Template| {
-        template.modify(move |style| {
-            if let Some(horizontal) = horizontal {
-                style.aligns.inline = horizontal;
-            }
+    let body = args.expect::<Template>("body")?;
+
+    Ok(Value::Template(Template::from_block(move |style| {
+        let mut style = style.clone();
+        if let Some(x) = x {
+            style.par_mut().align = x;
+        }
+
+        body.pack(&style).aligned(x, y)
+    })))
+}
+
+/// A node that aligns its child.
+#[derive(Debug, Hash)]
+pub struct AlignNode {
+    /// The node to be aligned.
+    pub child: PackedNode,
+    /// How to align the node horizontally and vertically.
+    pub aligns: Spec<Option<Align>>,
+}
+
+impl Layout for AlignNode {
+    fn layout(
+        &self,
+        ctx: &mut LayoutContext,
+        regions: &Regions,
+    ) -> Vec<Constrained<Rc<Frame>>> {
+        // Along axes with specified alignment, the child doesn't need to expand.
+        let mut pod = regions.clone();
+        pod.expand.x &= self.aligns.x.is_none();
+        pod.expand.y &= self.aligns.y.is_none();
+
+        let mut frames = self.child.layout(ctx, &pod);
+
+        for (Constrained { item: frame, cts }, (current, _)) in
+            frames.iter_mut().zip(regions.iter())
+        {
+            let canvas = Size::new(
+                if regions.expand.x { current.w } else { frame.size.w },
+                if regions.expand.y { current.h } else { frame.size.h },
+            );
 
-            if let Some(vertical) = vertical {
-                style.aligns.block = vertical;
+            let aligns = self.aligns.unwrap_or(Spec::new(Align::Left, Align::Top));
+            let offset = Point::new(
+                aligns.x.resolve(Length::zero() .. canvas.w - frame.size.w),
+                aligns.y.resolve(Length::zero() .. canvas.h - frame.size.h),
+            );
+
+            let frame = Rc::make_mut(frame);
+            frame.size = canvas;
+            frame.baseline += offset.y;
+
+            for (point, _) in &mut frame.elements {
+                *point += offset;
             }
-        });
 
-        if vertical.is_some() {
-            template.parbreak();
+            cts.expand = regions.expand;
+            cts.exact = current.to_spec().map(Some);
         }
-    };
-
-    Ok(if let Some(body) = body {
-        let mut template = Template::new();
-        template.save();
-        realign(&mut template);
-        template += body;
-        template.restore();
-        Value::Template(template)
-    } else {
-        realign(&mut ctx.template);
-        Value::None
-    })
+
+        frames
+    }
 }
diff --git a/src/library/flow.rs b/src/library/flow.rs
index 9fe8b95d..f58df536 100644
--- a/src/library/flow.rs
+++ b/src/library/flow.rs
@@ -1,7 +1,7 @@
 use std::fmt::{self, Debug, Formatter};
 
 use super::prelude::*;
-use super::Spacing;
+use super::{AlignNode, ParNode, Spacing};
 
 /// `flow`: A vertical flow of paragraphs and other layout nodes.
 pub fn flow(_: &mut EvalContext, args: &mut Args) -> TypResult<Value> {
@@ -27,7 +27,7 @@ pub fn flow(_: &mut EvalContext, args: &mut Args) -> TypResult<Value> {
             .iter()
             .map(|child| match child {
                 Child::Spacing(spacing) => FlowChild::Spacing(*spacing),
-                Child::Any(node) => FlowChild::Node(node.pack(style), style.aligns.block),
+                Child::Any(node) => FlowChild::Node(node.pack(style)),
             })
             .collect();
 
@@ -62,14 +62,14 @@ pub enum FlowChild {
     /// Vertical spacing between other children.
     Spacing(Spacing),
     /// A node and how to align it in the flow.
-    Node(PackedNode, Align),
+    Node(PackedNode),
 }
 
 impl Debug for FlowChild {
     fn fmt(&self, f: &mut Formatter) -> fmt::Result {
         match self {
             Self::Spacing(v) => write!(f, "Spacing({:?})", v),
-            Self::Node(node, _) => node.fmt(f),
+            Self::Node(node) => node.fmt(f),
         }
     }
 }
@@ -101,8 +101,8 @@ enum FlowItem {
     Absolute(Length),
     /// Fractional spacing between other items.
     Fractional(Fractional),
-    /// A layouted child node.
-    Frame(Rc<Frame>, Align),
+    /// A layouted child node and how to align it vertically.
+    Frame(Rc<Frame>, Spec<Align>),
 }
 
 impl<'a> FlowLayouter<'a> {
@@ -135,8 +135,8 @@ impl<'a> FlowLayouter<'a> {
                     self.items.push(FlowItem::Fractional(v));
                     self.fr += v;
                 }
-                FlowChild::Node(ref node, align) => {
-                    self.layout_node(ctx, node, align);
+                FlowChild::Node(ref node) => {
+                    self.layout_node(ctx, node);
                 }
             }
         }
@@ -156,7 +156,17 @@ impl<'a> FlowLayouter<'a> {
     }
 
     /// Layout a node.
-    fn layout_node(&mut self, ctx: &mut LayoutContext, node: &PackedNode, align: Align) {
+    fn layout_node(&mut self, ctx: &mut LayoutContext, node: &PackedNode) {
+        let aligns = Spec::new(
+            // For non-expanding paragraphs it is crucial that we align the
+            // whole paragraph according to its internal alignment.
+            node.downcast::<ParNode>().map_or(Align::Left, |node| node.align),
+            // Vertical align node alignment is respected by the flow node.
+            node.downcast::<AlignNode>()
+                .and_then(|node| node.aligns.y)
+                .unwrap_or(Align::Top),
+        );
+
         let frames = node.layout(ctx, &self.regions);
         let len = frames.len();
         for (i, frame) in frames.into_iter().enumerate() {
@@ -165,7 +175,7 @@ impl<'a> FlowLayouter<'a> {
             self.used.h += size.h;
             self.used.w.set_max(size.w);
             self.regions.current.h -= size.h;
-            self.items.push(FlowItem::Frame(frame.item, align));
+            self.items.push(FlowItem::Frame(frame.item, aligns));
 
             if i + 1 < len {
                 self.finish_region();
@@ -177,43 +187,44 @@ impl<'a> FlowLayouter<'a> {
     fn finish_region(&mut self) {
         // Determine the size of the flow in this region dependening on whether
         // the region expands.
-        let size = Size::new(
+        let mut size = Size::new(
             if self.expand.x { self.full.w } else { self.used.w },
-            if self.expand.y || (self.fr.get() > 0.0 && self.full.h.is_finite()) {
-                self.full.h
-            } else {
-                self.used.h
-            },
+            if self.expand.y { self.full.h } else { self.used.h },
         );
 
+        // Account for fractional spacing in the size calculation.
+        let remaining = self.full.h - self.used.h;
+        if self.fr.get() > 0.0 && self.full.h.is_finite() {
+            self.used.h = self.full.h;
+            size.h = self.full.h;
+        }
+
         let mut output = Frame::new(size, size.h);
         let mut before = Length::zero();
-        let mut ruler = Align::Start;
+        let mut ruler = Align::Top;
         let mut first = true;
 
         // Place all frames.
         for item in self.items.drain(..) {
             match item {
                 FlowItem::Absolute(v) => before += v,
-                FlowItem::Fractional(v) => {
-                    let remaining = self.full.h - self.used.h;
-                    before += v.resolve(self.fr, remaining);
-                }
-                FlowItem::Frame(frame, align) => {
-                    ruler = ruler.max(align);
-
-                    // Align vertically.
-                    let range = before .. before + size.h - self.used.h;
-                    let y = ruler.resolve(Dir::TTB, range);
+                FlowItem::Fractional(v) => before += v.resolve(self.fr, remaining),
+                FlowItem::Frame(frame, aligns) => {
+                    ruler = ruler.max(aligns.y);
+
+                    // Align horizontally and vertically.
+                    let x = aligns.x.resolve(Length::zero() .. size.w - frame.size.w);
+                    let y = ruler.resolve(before .. before + size.h - self.used.h);
+                    let pos = Point::new(x, y);
                     before += frame.size.h;
 
                     // The baseline of the flow is that of the first frame.
                     if first {
-                        output.baseline = y + frame.baseline;
+                        output.baseline = pos.y + frame.baseline;
                         first = false;
                     }
 
-                    output.push_frame(Point::new(Length::zero(), y), frame);
+                    output.push_frame(pos, frame);
                 }
             }
         }
diff --git a/src/library/image.rs b/src/library/image.rs
index ea9a050c..ea4f775c 100644
--- a/src/library/image.rs
+++ b/src/library/image.rs
@@ -54,9 +54,9 @@ impl Layout for ImageNode {
         let canvas = if expand.x && expand.y {
             current
         } else if expand.x || (wide && current.w.is_finite()) {
-            Size::new(current.w, current.w.safe_div(pixel_ratio))
+            Size::new(current.w, current.h.min(current.w.safe_div(pixel_ratio)))
         } else if current.h.is_finite() {
-            Size::new(current.h * pixel_ratio, current.h)
+            Size::new(current.w.min(current.h * pixel_ratio), current.h)
         } else {
             Size::new(Length::pt(pixel_w), Length::pt(pixel_h))
         };
diff --git a/src/library/mod.rs b/src/library/mod.rs
index fdede8bd..4f33b715 100644
--- a/src/library/mod.rs
+++ b/src/library/mod.rs
@@ -117,12 +117,10 @@ 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("start", Align::Start);
-    std.def_const("center", Align::Center);
-    std.def_const("end", Align::End);
     std.def_const("left", Align::Left);
-    std.def_const("right", Align::Right);
     std.def_const("top", Align::Top);
+    std.def_const("center", Align::Center);
+    std.def_const("right", Align::Right);
     std.def_const("bottom", Align::Bottom);
     std.def_const("serif", FontFamily::Serif);
     std.def_const("sans-serif", FontFamily::SansSerif);
diff --git a/src/library/par.rs b/src/library/par.rs
index 64b68c68..67c2969b 100644
--- a/src/library/par.rs
+++ b/src/library/par.rs
@@ -36,6 +36,7 @@ pub fn par(ctx: &mut EvalContext, args: &mut Args) -> TypResult<Value> {
 
         if let Some(dir) = dir {
             par.dir = dir;
+            par.align = if dir == Dir::LTR { Align::Left } else { Align::Right };
         }
 
         if let Some(leading) = leading {
@@ -55,8 +56,10 @@ pub fn par(ctx: &mut EvalContext, args: &mut Args) -> TypResult<Value> {
 /// A node that arranges its children into a paragraph.
 #[derive(Debug, Hash)]
 pub struct ParNode {
-    /// The inline direction of this paragraph.
+    /// The text direction (either LTR or RTL).
     pub dir: Dir,
+    /// How to align text in its line.
+    pub align: Align,
     /// The spacing to insert between each line.
     pub leading: Length,
     /// The children to be arranged in a paragraph.
@@ -124,9 +127,9 @@ pub enum ParChild {
     /// Spacing between other nodes.
     Spacing(Spacing),
     /// A run of text and how to align it in its line.
-    Text(EcoString, Align, Rc<TextStyle>),
+    Text(EcoString, Rc<TextStyle>),
     /// Any child node and how to align it in its line.
-    Node(PackedNode, Align),
+    Node(PackedNode),
     /// A decoration that applies until a matching `Undecorate`.
     Decorate(Decoration),
     /// The end of a decoration.
@@ -137,8 +140,8 @@ impl Debug for ParChild {
     fn fmt(&self, f: &mut Formatter) -> fmt::Result {
         match self {
             Self::Spacing(v) => write!(f, "Spacing({:?})", v),
-            Self::Text(text, ..) => write!(f, "Text({:?})", text),
-            Self::Node(node, ..) => node.fmt(f),
+            Self::Text(text, _) => write!(f, "Text({:?})", text),
+            Self::Node(node) => node.fmt(f),
             Self::Decorate(deco) => write!(f, "Decorate({:?})", deco),
             Self::Undecorate => write!(f, "Undecorate"),
         }
@@ -148,9 +151,9 @@ impl Debug for ParChild {
 /// A paragraph representation in which children are already layouted and text
 /// is separated into shapable runs.
 struct ParLayouter<'a> {
-    /// The top-level direction.
-    dir: Dir,
-    /// The line spacing.
+    /// How to align text in its line.
+    align: Align,
+    /// The spacing to insert between each line.
     leading: Length,
     /// Bidirectional text embedding levels for the paragraph.
     bidi: BidiInfo<'a>,
@@ -172,9 +175,9 @@ enum ParItem<'a> {
     /// Fractional spacing between other items.
     Fractional(Fractional),
     /// A shaped text run with consistent direction.
-    Text(ShapedText<'a>, Align),
+    Text(ShapedText<'a>),
     /// A layouted child node.
-    Frame(Frame, Align),
+    Frame(Frame),
 }
 
 impl<'a> ParLayouter<'a> {
@@ -202,7 +205,7 @@ impl<'a> ParLayouter<'a> {
                     items.push(ParItem::Fractional(v));
                     ranges.push(range);
                 }
-                ParChild::Text(_, align, ref style) => {
+                ParChild::Text(_, ref style) => {
                     // TODO: Also split by language and script.
                     let mut cursor = range.start;
                     for (level, group) in bidi.levels[range].group_by_key(|&lvl| lvl) {
@@ -211,16 +214,16 @@ impl<'a> ParLayouter<'a> {
                         let subrange = start .. cursor;
                         let text = &bidi.text[subrange.clone()];
                         let shaped = shape(ctx, text, style, level.dir());
-                        items.push(ParItem::Text(shaped, align));
+                        items.push(ParItem::Text(shaped));
                         ranges.push(subrange);
                     }
                 }
-                ParChild::Node(ref node, align) => {
+                ParChild::Node(ref node) => {
                     let size = Size::new(regions.current.w, regions.base.h);
                     let expand = Spec::splat(false);
                     let pod = Regions::one(size, regions.base, expand);
                     let frame = node.layout(ctx, &pod).remove(0);
-                    items.push(ParItem::Frame(Rc::take(frame.item), align));
+                    items.push(ParItem::Frame(Rc::take(frame.item)));
                     ranges.push(range);
                 }
                 ParChild::Decorate(ref deco) => {
@@ -234,7 +237,7 @@ impl<'a> ParLayouter<'a> {
         }
 
         Self {
-            dir: par.dir,
+            align: par.align,
             leading: par.leading,
             bidi,
             items,
@@ -392,7 +395,7 @@ impl<'a> LineLayout<'a> {
 
         // Reshape the last item if it's split in half.
         let mut last = None;
-        if let Some((ParItem::Text(shaped, align), rest)) = items.split_last() {
+        if let Some((ParItem::Text(shaped), rest)) = items.split_last() {
             // Compute the range we want to shape, trimming whitespace at the
             // end of the line.
             let base = par.ranges[last_idx].start;
@@ -408,7 +411,7 @@ impl<'a> LineLayout<'a> {
                 if !range.is_empty() || rest.is_empty() {
                     // Reshape that part.
                     let reshaped = shaped.reshape(ctx, range);
-                    last = Some(ParItem::Text(reshaped, *align));
+                    last = Some(ParItem::Text(reshaped));
                 }
 
                 items = rest;
@@ -418,7 +421,7 @@ impl<'a> LineLayout<'a> {
 
         // Reshape the start item if it's split in half.
         let mut first = None;
-        if let Some((ParItem::Text(shaped, align), rest)) = items.split_first() {
+        if let Some((ParItem::Text(shaped), rest)) = items.split_first() {
             // Compute the range we want to shape.
             let Range { start: base, end: first_end } = par.ranges[first_idx];
             let start = line.start;
@@ -429,7 +432,7 @@ impl<'a> LineLayout<'a> {
             if range.len() < shaped.text.len() {
                 if !range.is_empty() {
                     let reshaped = shaped.reshape(ctx, range);
-                    first = Some(ParItem::Text(reshaped, *align));
+                    first = Some(ParItem::Text(reshaped));
                 }
 
                 items = rest;
@@ -446,8 +449,8 @@ impl<'a> LineLayout<'a> {
             match *item {
                 ParItem::Absolute(v) => width += v,
                 ParItem::Fractional(v) => fr += v,
-                ParItem::Text(ShapedText { size, baseline, .. }, _)
-                | ParItem::Frame(Frame { size, baseline, .. }, _) => {
+                ParItem::Text(ShapedText { size, baseline, .. })
+                | ParItem::Frame(Frame { size, baseline, .. }) => {
                     width += size.w;
                     top.set_max(baseline);
                     bottom.set_max(size.h - baseline);
@@ -475,10 +478,9 @@ impl<'a> LineLayout<'a> {
 
         let mut output = Frame::new(size, self.baseline);
         let mut offset = Length::zero();
-        let mut ruler = Align::Start;
 
         for (range, item) in self.reordered() {
-            let mut position = |mut frame: Frame, align: Align| {
+            let mut position = |mut frame: Frame| {
                 // Decorate.
                 for (deco_range, deco) in &self.par.decos {
                     if deco_range.contains(&range.start) {
@@ -486,9 +488,7 @@ impl<'a> LineLayout<'a> {
                     }
                 }
 
-                // FIXME: Ruler alignment for RTL.
-                ruler = ruler.max(align);
-                let x = ruler.resolve(self.par.dir, offset .. remaining + offset);
+                let x = self.par.align.resolve(offset .. remaining + offset);
                 let y = self.baseline - frame.baseline;
                 offset += frame.size.w;
 
@@ -499,8 +499,8 @@ impl<'a> LineLayout<'a> {
             match *item {
                 ParItem::Absolute(v) => offset += v,
                 ParItem::Fractional(v) => offset += v.resolve(self.fr, remaining),
-                ParItem::Text(ref shaped, align) => position(shaped.build(), align),
-                ParItem::Frame(ref frame, align) => position(frame.clone(), align),
+                ParItem::Text(ref shaped) => position(shaped.build()),
+                ParItem::Frame(ref frame) => position(frame.clone()),
             }
         }
 
diff --git a/src/library/shape.rs b/src/library/shape.rs
index dbd6eea7..5d9b4152 100644
--- a/src/library/shape.rs
+++ b/src/library/shape.rs
@@ -140,7 +140,7 @@ impl Layout for ShapeNode {
             // When there's no child, fill the area if expansion is on,
             // otherwise fall back to a default size.
             let default = Length::pt(30.0);
-            let size = Size::new(
+            let mut size = Size::new(
                 if regions.expand.x {
                     regions.current.w
                 } else {
@@ -154,6 +154,11 @@ impl Layout for ShapeNode {
                 if regions.expand.y { regions.current.h } else { default },
             );
 
+            if matches!(self.kind, ShapeKind::Square | ShapeKind::Circle) {
+                size.w = size.w.min(size.h);
+                size.h = size.w;
+            }
+
             Frame::new(size, size.h)
         };
 
@@ -171,6 +176,13 @@ impl Layout for ShapeNode {
             frame.prepend(pos, Element::Geometry(geometry, fill));
         }
 
+        // Ensure frame size matches regions size if expansion is on.
+        let expand = regions.expand;
+        frame.size = Size::new(
+            if expand.x { regions.current.w } else { frame.size.w },
+            if expand.y { regions.current.h } else { frame.size.h },
+        );
+
         // Return tight constraints for now.
         let mut cts = Constraints::new(regions.expand);
         cts.exact = regions.current.to_spec().map(Some);
diff --git a/src/library/sized.rs b/src/library/sized.rs
index 6394b0f4..3089f90b 100644
--- a/src/library/sized.rs
+++ b/src/library/sized.rs
@@ -23,7 +23,7 @@ pub fn block(_: &mut EvalContext, args: &mut Args) -> TypResult<Value> {
 /// A node that sizes its child.
 #[derive(Debug, Hash)]
 pub struct SizedNode {
-    /// The node to-be-sized.
+    /// The node to be sized.
     pub child: PackedNode,
     /// How to size the node horizontally and vertically.
     pub sizing: Spec<Option<Linear>>,
diff --git a/src/library/stack.rs b/src/library/stack.rs
index 61406e8e..7ac7e6ee 100644
--- a/src/library/stack.rs
+++ b/src/library/stack.rs
@@ -1,7 +1,7 @@
 use std::fmt::{self, Debug, Formatter};
 
 use super::prelude::*;
-use super::Spacing;
+use super::{AlignNode, Spacing};
 
 /// `stack`: Stack children along an axis.
 pub fn stack(_: &mut EvalContext, args: &mut Args) -> TypResult<Value> {
@@ -118,7 +118,7 @@ enum StackItem {
     /// Fractional spacing between other items.
     Fractional(Fractional),
     /// A layouted child node.
-    Frame(Rc<Frame>),
+    Frame(Rc<Frame>, Align),
 }
 
 impl<'a> StackLayouter<'a> {
@@ -176,6 +176,12 @@ impl<'a> StackLayouter<'a> {
 
     /// Layout a node.
     fn layout_node(&mut self, ctx: &mut LayoutContext, node: &PackedNode) {
+        // Align nodes' block-axis alignment is respected by the stack node.
+        let align = node
+            .downcast::<AlignNode>()
+            .and_then(|node| node.aligns.get(self.axis))
+            .unwrap_or(self.stack.dir.start().into());
+
         let frames = node.layout(ctx, &self.regions);
         let len = frames.len();
         for (i, frame) in frames.into_iter().enumerate() {
@@ -184,7 +190,7 @@ impl<'a> StackLayouter<'a> {
             self.used.block += size.block;
             self.used.inline.set_max(size.inline);
             *self.regions.current.get_mut(self.axis) -= size.block;
-            self.items.push(StackItem::Frame(frame.item));
+            self.items.push(StackItem::Frame(frame.item, align));
 
             if i + 1 < len {
                 self.finish_region();
@@ -204,29 +210,35 @@ impl<'a> StackLayouter<'a> {
 
         // Expand fully if there are fr spacings.
         let full = self.full.get(self.axis);
+        let remaining = full - self.used.block;
         if self.fr.get() > 0.0 && full.is_finite() {
+            self.used.block = full;
             size.set(self.axis, full);
         }
 
         let mut output = Frame::new(size, size.h);
         let mut before = Length::zero();
+        let mut ruler: Align = self.stack.dir.start().into();
 
         // Place all frames.
         for item in self.items.drain(..) {
             match item {
                 StackItem::Absolute(v) => before += v,
-                StackItem::Fractional(v) => {
-                    let remaining = self.full.get(self.axis) - self.used.block;
-                    before += v.resolve(self.fr, remaining)
-                }
-                StackItem::Frame(frame) => {
+                StackItem::Fractional(v) => before += v.resolve(self.fr, remaining),
+                StackItem::Frame(frame, align) => {
+                    ruler = ruler.max(align);
+
+                    // Align along the block axis.
                     let parent = size.get(self.axis);
                     let child = frame.size.get(self.axis);
-                    let block = if self.stack.dir.is_positive() {
-                        before
+                    let block = ruler.resolve(if self.stack.dir.is_positive() {
+                        let after = self.used.block - before;
+                        before .. parent - after
                     } else {
-                        parent - (before + child)
-                    };
+                        let before_with_self = before + child;
+                        let after = self.used.block - before_with_self;
+                        after .. parent - before_with_self
+                    });
 
                     before += child;
 
-- 
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