Hanging indent

5 files changed, 74 insertions, 50 deletions

diff --git a/library/src/layout/par.rs b/library/src/layout/par.rs
index 2d7c5d62..244a61a9 100644
--- a/library/src/layout/par.rs
+++ b/library/src/layout/par.rs
@@ -20,7 +20,7 @@ use crate::text::{
 ///
 /// ## Example
 /// ```example
-/// #set par(indent: 1em, justify: true)
+/// #set par(first-line-indent: 1em, justify: true)
 /// #show par: set block(spacing: 0.65em)
 ///
 /// We proceed by contradiction.
@@ -39,17 +39,6 @@ use crate::text::{
 /// Category: layout
 #[node(Construct)]
 pub struct ParNode {
-    /// The indent the first line of a consecutive paragraph should have.
-    ///
-    /// The first paragraph on a page will never be indented.
-    ///
-    /// By typographic convention, paragraph breaks are indicated by either some
-    /// space between paragraphs or indented first lines. Consider turning the
-    /// [paragraph spacing]($func/block.spacing) off when using this property
-    /// (e.g. using `[#show par: set block(spacing: 0pt)]`).
-    #[resolve]
-    pub indent: Length,
-
     /// The spacing between lines.
     ///
     /// The default value is `{0.65em}`.
@@ -95,6 +84,21 @@ pub struct ParNode {
     #[default]
     pub linebreaks: Smart<Linebreaks>,
 
+    /// The indent the first line of a consecutive paragraph should have.
+    ///
+    /// The first paragraph on a page will never be indented.
+    ///
+    /// By typographic convention, paragraph breaks are indicated by either some
+    /// space between paragraphs or indented first lines. Consider turning the
+    /// [paragraph spacing]($func/block.spacing) off when using this property
+    /// (e.g. using `[#show par: set block(spacing: 0pt)]`).
+    #[resolve]
+    pub first_line_indent: Length,
+
+    /// The indent all but the first line of a paragraph should have.
+    #[resolve]
+    pub hanging_indent: Length,
+
     /// The contents of the paragraph.
     #[external]
     pub body: Content,
@@ -153,7 +157,7 @@ impl ParNode {
             let p = prepare(&mut vt, &children, &text, segments, spans, styles, region)?;
 
             // Break the paragraph into lines.
-            let lines = linebreak(&vt, &p, region.x);
+            let lines = linebreak(&vt, &p, region.x - p.hang);
 
             // Stack the lines into one frame per region.
             finalize(&mut vt, &p, &lines, region, expand)
@@ -261,6 +265,8 @@ struct Preparation<'a> {
     align: Align,
     /// Whether to justify the paragraph.
     justify: bool,
+    /// The paragraph's hanging indent.
+    hang: Abs,
 }
 
 impl<'a> Preparation<'a> {
@@ -509,8 +515,8 @@ fn collect<'a>(
     let mut iter = children.iter().peekable();
 
     if consecutive {
-        let indent = ParNode::indent_in(*styles);
-        if !indent.is_zero()
+        let first_line_indent = ParNode::first_line_indent_in(*styles);
+        if !first_line_indent.is_zero()
             && children
                 .iter()
                 .find_map(|child| {
@@ -527,10 +533,16 @@ fn collect<'a>(
                 .unwrap_or_default()
         {
             full.push(SPACING_REPLACE);
-            segments.push((Segment::Spacing(indent.into()), *styles));
+            segments.push((Segment::Spacing(first_line_indent.into()), *styles));
         }
     }
 
+    let hang = ParNode::hanging_indent_in(*styles);
+    if !hang.is_zero() {
+        full.push(SPACING_REPLACE);
+        segments.push((Segment::Spacing((-hang).into()), *styles));
+    }
+
     while let Some(mut child) = iter.next() {
         let outer = styles;
         let mut styles = *styles;
@@ -681,6 +693,7 @@ fn prepare<'a>(
         lang: shared_get(styles, children, TextNode::lang_in),
         align: AlignNode::alignment_in(styles).x.resolve(styles),
         justify: ParNode::justify_in(styles),
+        hang: ParNode::hanging_indent_in(styles),
     })
 }
 
@@ -1158,7 +1171,7 @@ fn finalize(
     let width = if !region.x.is_finite()
         || (!expand && lines.iter().all(|line| line.fr().is_zero()))
     {
-        lines.iter().map(|line| line.width).max().unwrap_or_default()
+        p.hang + lines.iter().map(|line| line.width).max().unwrap_or_default()
     } else {
         region.x
     };
@@ -1204,11 +1217,14 @@ fn commit(
     width: Abs,
     full: Abs,
 ) -> SourceResult<Frame> {
-    let mut remaining = width - line.width;
+    let mut remaining = width - line.width - p.hang;
     let mut offset = Abs::zero();
 
     // Reorder the line from logical to visual order.
-    let reordered = reorder(line);
+    let (reordered, starts_rtl) = reorder(line);
+    if !starts_rtl {
+        offset += p.hang;
+    }
 
     // Handle hanging punctuation to the left.
     if let Some(Item::Text(text)) = reordered.first() {
@@ -1308,12 +1324,12 @@ fn commit(
 }
 
 /// Return a line's items in visual order.
-fn reorder<'a>(line: &'a Line<'a>) -> Vec<&Item<'a>> {
+fn reorder<'a>(line: &'a Line<'a>) -> (Vec<&Item<'a>>, bool) {
     let mut reordered = vec![];
 
     // The bidi crate doesn't like empty lines.
     if line.trimmed.is_empty() {
-        return line.slice(line.trimmed.clone()).collect();
+        return (line.slice(line.trimmed.clone()).collect(), false);
     }
 
     // Find the paragraph that contains the line.
@@ -1326,6 +1342,7 @@ fn reorder<'a>(line: &'a Line<'a>) -> Vec<&Item<'a>> {
 
     // Compute the reordered ranges in visual order (left to right).
     let (levels, runs) = line.bidi.visual_runs(para, line.trimmed.clone());
+    let starts_rtl = levels.first().map_or(false, |level| level.is_rtl());
 
     // Collect the reordered items.
     for run in runs {
@@ -1343,7 +1360,7 @@ fn reorder<'a>(line: &'a Line<'a>) -> Vec<&Item<'a>> {
         }
     }
 
-    reordered
+    (reordered, starts_rtl)
 }
 
 /// How much a character should hang into the end margin.
diff --git a/library/src/layout/terms.rs b/library/src/layout/terms.rs
index b2f45446..853dd32d 100644
--- a/library/src/layout/terms.rs
+++ b/library/src/layout/terms.rs
@@ -1,4 +1,5 @@
-use crate::layout::{BlockNode, GridLayouter, HNode, ParNode, Sizing, Spacing};
+use super::{HNode, VNode};
+use crate::layout::{BlockNode, ParNode, Spacing};
 use crate::prelude::*;
 use crate::text::{SpaceNode, TextNode};
 
@@ -42,7 +43,6 @@ pub struct TermsNode {
     pub tight: bool,
 
     /// The indentation of each item's term.
-    #[resolve]
     pub indent: Length,
 
     /// The hanging indent of the description.
@@ -52,7 +52,6 @@ pub struct TermsNode {
     /// / Term: This term list does not
     ///   make use of hanging indents.
     /// ```
-    #[resolve]
     #[default(Em::new(1.0).into())]
     pub hanging_indent: Length,
 
@@ -85,7 +84,7 @@ impl Layout for TermsNode {
         regions: Regions,
     ) -> SourceResult<Fragment> {
         let indent = self.indent(styles);
-        let body_indent = self.hanging_indent(styles);
+        let hanging_indent = self.hanging_indent(styles);
         let gutter = if self.tight(styles) {
             ParNode::leading_in(styles).into()
         } else {
@@ -93,29 +92,22 @@ impl Layout for TermsNode {
                 .unwrap_or_else(|| BlockNode::below_in(styles).amount())
         };
 
-        let mut cells = vec![];
-        for child in self.children() {
-            let body = Content::sequence(vec![
-                HNode::new((-body_indent).into()).pack(),
-                (child.term() + TextNode::packed(':')).strong(),
-                SpaceNode::new().pack(),
-                child.description(),
-            ]);
-
-            cells.push(Content::empty());
-            cells.push(body);
+        let mut seq = vec![];
+        for (i, child) in self.children().into_iter().enumerate() {
+            if i > 0 {
+                seq.push(VNode::new(gutter).with_weakness(1).pack());
+            }
+            if indent.is_zero() {
+                seq.push(HNode::new(indent.into()).pack());
+            }
+            seq.push((child.term() + TextNode::packed(':')).strong());
+            seq.push(SpaceNode::new().pack());
+            seq.push(child.description());
         }
 
-        let layouter = GridLayouter::new(
-            vt,
-            Axes::with_x(&[Sizing::Rel((indent + body_indent).into()), Sizing::Auto]),
-            Axes::with_y(&[gutter.into()]),
-            &cells,
-            regions,
-            styles,
-        );
-
-        Ok(layouter.layout()?.fragment)
+        Content::sequence(seq)
+            .styled(ParNode::set_hanging_indent(hanging_indent + indent))
+            .layout(vt, styles, regions)
     }
 }
 
diff --git a/tests/ref/layout/par-indent.png b/tests/ref/layout/par-indent.png
index 269c0024..6e5e25b6 100644
--- a/tests/ref/layout/par-indent.png
+++ b/tests/ref/layout/par-indent.png
diff --git a/tests/typ/layout/par-indent.typ b/tests/typ/layout/par-indent.typ
index 0cb937bf..4890e5dc 100644
--- a/tests/typ/layout/par-indent.typ
+++ b/tests/typ/layout/par-indent.typ
@@ -1,7 +1,7 @@
 // Test paragraph indent.
 
 ---
-#set par(indent: 12pt, leading: 5pt)
+#set par(first-line-indent: 12pt, leading: 5pt)
 #set block(spacing: 5pt)
 #show heading: set text(size: 10pt)
 
@@ -31,7 +31,22 @@ starts a paragraph without indent.
 
 ---
 // This is madness.
-#set par(indent: 12pt)
+#set par(first-line-indent: 12pt)
 Why would anybody ever ...
 
 ... want spacing and indent?
+
+---
+// Test hanging indent.
+#set par(hanging-indent: 15pt, justify: true)
+#lorem(10)
+
+---
+#set par(hanging-indent: 1em)
+Welcome \ here. Does this work well?
+
+---
+#set par(hanging-indent: 2em)
+#set text(dir: rtl)
+لآن وقد أظلم الليل وبدأت النجوم
+تنضخ وجه الطبيعة التي أعْيَتْ من طول ما انبعثت في النهار
diff --git a/tests/typ/layout/par-justify.typ b/tests/typ/layout/par-justify.typ
index 5a9012d1..24d3ab38 100644
--- a/tests/typ/layout/par-justify.typ
+++ b/tests/typ/layout/par-justify.typ
@@ -2,7 +2,7 @@
 ---
 #set page(width: 180pt)
 #set block(spacing: 5pt)
-#set par(justify: true, indent: 14pt, leading: 5pt)
+#set par(justify: true, first-line-indent: 14pt, leading: 5pt)
 
 This text is justified, meaning that spaces are stretched so that the text
 forms a "block" with flush edges at both sides.