Merge 4aa6dcf578ce3fde6209369c358bde012150146c into 78355421ad73fdcbe93b4acca890b439c4b6f98d

crates/typst-layout/src/inline/shaping.rs

@@ -10,6 +10,7 @@ use typst_library::World;
 use typst_library::engine::Engine;
 use typst_library::foundations::{Smart, StyleChain};
 use typst_library::layout::{Abs, Dir, Em, Frame, FrameItem, Point, Size};
+use typst_library::model::{Microtype, ParElem};
 use typst_library::text::{
     Font, FontFamily, FontVariant, Glyph, Lang, Region, ShiftSettings, TextEdgeBounds,
     TextElem, TextItem, families, features, is_default_ignorable, language, variant,
@@ -144,7 +145,11 @@ impl ShapedGlyph {
             || self.c.is_ascii_digit()
     }
 
-    pub fn base_adjustability(&self, style: CjkPunctStyle) -> Adjustability {
+    pub fn base_adjustability(
+        &self,
+        style: CjkPunctStyle,
+        microtype: Microtype,
+    ) -> Adjustability {
         let width = self.x_advance;
         if self.is_space() {
             Adjustability {
@@ -168,7 +173,10 @@ impl ShapedGlyph {
                 shrinkability: (width / 4.0, width / 4.0),
             }
         } else {
-            Adjustability::default()
+            Adjustability {
+                stretchability: (Em::zero(), microtype.max_expand.em),
+                shrinkability: (Em::zero(), microtype.max_retract.em),
+            }
         }
     }
 
@@ -1106,9 +1114,10 @@ fn track_and_space(ctx: &mut ShapingContext) {
 /// and CJK punctuation adjustments according to Chinese Layout Requirements.
 fn calculate_adjustability(ctx: &mut ShapingContext, lang: Lang, region: Option<Region>) {
     let style = cjk_punct_style(lang, region);
+    let microtype = ParElem::microtype_in(ctx.styles);
 
     for glyph in &mut ctx.glyphs {
-        glyph.adjustability = glyph.base_adjustability(style);
+        glyph.adjustability = glyph.base_adjustability(style, microtype);
     }
 
     let mut glyphs = ctx.glyphs.iter_mut().peekable();

crates/typst-library/src/model/par.rs

@@ -136,6 +136,9 @@ pub struct ParElem {
     #[default(false)]
     pub justify: bool,
 
+    /// Microtypographical settings that are used during justification.
+    pub microtype: Microtype,
+
     /// How to determine line breaks.
     ///
     /// When this property is set to `{auto}`, its default value, optimized line
@@ -224,6 +227,36 @@ impl ParElem {
     type ParLine;
 }
 
+/// Configuration for microtypographical settings to be used during
+/// justification.
+#[derive(Debug, Default, Copy, Clone, PartialEq, Hash)]
+pub struct Microtype {
+    /// How much a glyph is allowed to translate into its neighbor.
+    pub max_retract: Length,
+    /// How much a glyph is allowed to translate away from its neighbor.
+    pub max_expand: Length,
+}
+
+cast! {
+    Microtype,
+    self => Value::Dict(self.into()),
+    mut dict: Dict => {
+        let max_retract = dict.take("max-retract")?.cast()?;
+        let max_expand = dict.take("max-expand")?.cast()?;
+        dict.finish(&["max-retract", "max-expand"])?;
+        Self { max_retract, max_expand }
+    },
+}
+
+impl From<Microtype> for Dict {
+    fn from(microtype: Microtype) -> Self {
+        dict! {
+            "max-retract" => microtype.max_retract,
+            "max-expand" => microtype.max_expand,
+        }
+    }
+}
+
 /// How to determine line breaks in a paragraph.
 #[derive(Debug, Copy, Clone, Eq, PartialEq, Hash, Cast)]
 pub enum Linebreaks {