Expand text link boxes vertically by half the leading spacing (#6252)

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

@@ -20,7 +20,7 @@ use unicode_bidi::{BidiInfo, Level as BidiLevel};
 use unicode_script::{Script, UnicodeScript};
 
 use super::{decorate, Item, Range, SpanMapper};
-use crate::modifiers::{FrameModifiers, FrameModify};
+use crate::modifiers::FrameModifyText;
 
 /// The result of shaping text.
 ///
@@ -327,7 +327,7 @@ impl<'a> ShapedText<'a> {
             offset += width;
         }
 
-        frame.modify(&FrameModifiers::get_in(self.styles));
+        frame.modify_text(self.styles);
         frame
     }
 

crates/typst-layout/src/modifiers.rs

@@ -1,6 +1,6 @@
 use typst_library::foundations::StyleChain;
-use typst_library::layout::{Fragment, Frame, FrameItem, HideElem, Point};
-use typst_library::model::{Destination, LinkElem};
+use typst_library::layout::{Abs, Fragment, Frame, FrameItem, HideElem, Point, Sides};
+use typst_library::model::{Destination, LinkElem, ParElem};
 
 /// Frame-level modifications resulting from styles that do not impose any
 /// layout structure.
@@ -52,14 +52,7 @@ pub trait FrameModify {
 
 impl FrameModify for Frame {
     fn modify(&mut self, modifiers: &FrameModifiers) {
-        if let Some(dest) = &modifiers.dest {
-            let size = self.size();
-            self.push(Point::zero(), FrameItem::Link(dest.clone(), size));
-        }
-
-        if modifiers.hidden {
-            self.hide();
-        }
+        modify_frame(self, modifiers, None);
     }
 }
 
@@ -82,6 +75,41 @@ where
     }
 }
 
+pub trait FrameModifyText {
+    /// Resolve and apply [`FrameModifiers`] for this text frame.
+    fn modify_text(&mut self, styles: StyleChain);
+}
+
+impl FrameModifyText for Frame {
+    fn modify_text(&mut self, styles: StyleChain) {
+        let modifiers = FrameModifiers::get_in(styles);
+        let expand_y = 0.5 * ParElem::leading_in(styles);
+        let outset = Sides::new(Abs::zero(), expand_y, Abs::zero(), expand_y);
+        modify_frame(self, &modifiers, Some(outset));
+    }
+}
+
+fn modify_frame(
+    frame: &mut Frame,
+    modifiers: &FrameModifiers,
+    link_box_outset: Option<Sides<Abs>>,
+) {
+    if let Some(dest) = &modifiers.dest {
+        let mut pos = Point::zero();
+        let mut size = frame.size();
+        if let Some(outset) = link_box_outset {
+            pos.y -= outset.top;
+            pos.x -= outset.left;
+            size += outset.sum_by_axis();
+        }
+        frame.push(pos, FrameItem::Link(dest.clone(), size));
+    }
+
+    if modifiers.hidden {
+        frame.hide();
+    }
+}
+
 /// Performs layout and modification in one step.
 ///
 /// This just runs `layout(styles).modified(&FrameModifiers::get_in(styles))`,