Resolve lengths in math with scaled font size (#5168)

Author: EpicEricEE

crates/typst/src/layout/rel.rs

@@ -86,6 +86,12 @@ impl Rel<Length> {
             None
         }
     }
+
+    /// Convert to a relative length with the absolute part resolved at the
+    /// given font size.
+    pub fn at(self, font_size: Abs) -> Rel<Abs> {
+        self.map(|abs| abs.at(font_size))
+    }
 }
 
 impl<T: Numeric + Debug> Debug for Rel<T> {

crates/typst/src/math/accent.rs

@@ -1,11 +1,11 @@
 use crate::diag::{bail, SourceResult};
 use crate::foundations::{
-    cast, elem, func, Content, NativeElement, Packed, Resolve, Smart, StyleChain, Value,
+    cast, elem, func, Content, NativeElement, Packed, Smart, StyleChain, Value,
 };
 use crate::layout::{Em, Frame, Length, Point, Rel, Size};
 use crate::math::{
-    style_cramped, FrameFragment, GlyphFragment, LayoutMath, MathContext, MathFragment,
-    Scaled,
+    scaled_font_size, style_cramped, FrameFragment, GlyphFragment, LayoutMath,
+    MathContext, MathFragment, Scaled,
 };
 use crate::text::TextElem;
 
@@ -123,7 +123,7 @@ impl LayoutMath for Packed<AccentElem> {
         let width = self
             .size(styles)
             .unwrap_or(Rel::one())
-            .resolve(styles)
+            .at(scaled_font_size(ctx, styles))
             .relative_to(base.width());
 
         // Forcing the accent to be at least as large as the base makes it too

crates/typst/src/math/cancel.rs

@@ -1,13 +1,11 @@
 use comemo::Track;
 
 use crate::diag::{At, SourceResult};
-use crate::foundations::{
-    cast, elem, Content, Context, Func, Packed, Resolve, Smart, StyleChain,
-};
+use crate::foundations::{cast, elem, Content, Context, Func, Packed, Smart, StyleChain};
 use crate::layout::{
     Abs, Angle, Frame, FrameItem, Length, Point, Ratio, Rel, Size, Transform,
 };
-use crate::math::{FrameFragment, LayoutMath, MathContext};
+use crate::math::{scaled_font_size, FrameFragment, LayoutMath, MathContext};
 use crate::syntax::Span;
 use crate::text::TextElem;
 use crate::visualize::{FixedStroke, Geometry, Stroke};
@@ -120,7 +118,7 @@ impl LayoutMath for Packed<CancelElem> {
         let mut body = body.into_frame();
         let body_size = body.size();
         let span = self.span();
-        let length = self.length(styles).resolve(styles);
+        let length = self.length(styles).at(scaled_font_size(ctx, styles));
 
         let stroke = self.stroke(styles).unwrap_or(FixedStroke {
             paint: TextElem::fill_in(styles).as_decoration(),

crates/typst/src/math/ctx.rs

@@ -11,7 +11,7 @@ use unicode_segmentation::UnicodeSegmentation;
 
 use crate::diag::SourceResult;
 use crate::engine::Engine;
-use crate::foundations::{Content, Packed, Resolve, StyleChain, StyleVec};
+use crate::foundations::{Content, Packed, StyleChain, StyleVec};
 use crate::introspection::{SplitLocator, TagElem};
 use crate::layout::{
     layout_frame, Abs, Axes, BoxElem, Em, Frame, HElem, PlaceElem, Region, Size, Spacing,
@@ -220,7 +220,7 @@ impl MathContext<'_, '_, '_> {
             if let Spacing::Rel(rel) = elem.amount() {
                 if rel.rel.is_zero() {
                     self.push(MathFragment::Spacing(
-                        rel.abs.resolve(styles),
+                        rel.abs.at(scaled_font_size(self, styles)),
                         elem.weak(styles),
                     ));
                 }

crates/typst/src/math/matrix.rs

@@ -63,7 +63,6 @@ pub struct VecElem {
     /// #set math.vec(gap: 1em)
     /// $ vec(1, 2) $
     /// ```
-    #[resolve]
     #[default(DEFAULT_ROW_GAP.into())]
     pub gap: Rel<Length>,
 
@@ -81,7 +80,7 @@ impl LayoutMath for Packed<VecElem> {
             styles,
             self.children(),
             self.align(styles),
-            self.gap(styles),
+            self.gap(styles).at(scaled_font_size(ctx, styles)),
             LeftRightAlternator::Right,
         )?;
 
@@ -182,7 +181,6 @@ pub struct MatElem {
     /// #set math.mat(row-gap: 1em)
     /// $ mat(1, 2; 3, 4) $
     /// ```
-    #[resolve]
     #[parse(
         let gap = args.named("gap")?;
         args.named("row-gap")?.or(gap)
@@ -196,7 +194,6 @@ pub struct MatElem {
     /// #set math.mat(column-gap: 1em)
     /// $ mat(1, 2; 3, 4) $
     /// ```
-    #[resolve]
     #[parse(args.named("column-gap")?.or(gap))]
     #[default(DEFAULT_COL_GAP.into())]
     pub column_gap: Rel<Length>,
@@ -268,14 +265,17 @@ impl LayoutMath for Packed<MatElem> {
             }
         }
 
+        let font_size = scaled_font_size(ctx, styles);
+        let column_gap = self.column_gap(styles).at(font_size);
+        let row_gap = self.row_gap(styles).at(font_size);
         let delim = self.delim(styles);
         let frame = layout_mat_body(
             ctx,
             styles,
             rows,
             self.align(styles),
             augment,
-            Axes::new(self.column_gap(styles), self.row_gap(styles)),
+            Axes::new(column_gap, row_gap),
             self.span(),
         )?;
 
@@ -322,7 +322,6 @@ pub struct CasesElem {
     /// #set math.cases(gap: 1em)
     /// $ x = cases(1, 2) $
     /// ```
-    #[resolve]
     #[default(DEFAULT_ROW_GAP.into())]
     pub gap: Rel<Length>,
 
@@ -340,7 +339,7 @@ impl LayoutMath for Packed<CasesElem> {
             styles,
             self.children(),
             FixedAlignment::Start,
-            self.gap(styles),
+            self.gap(styles).at(scaled_font_size(ctx, styles)),
             LeftRightAlternator::None,
         )?;
 

crates/typst/src/math/stretch.rs

@@ -2,10 +2,11 @@ use ttf_parser::math::{GlyphAssembly, GlyphConstruction, GlyphPart};
 use ttf_parser::LazyArray16;
 
 use crate::diag::SourceResult;
-use crate::foundations::{elem, Content, Packed, Resolve, Smart, StyleChain};
+use crate::foundations::{elem, Content, Packed, Smart, StyleChain};
 use crate::layout::{Abs, Axis, Frame, Length, Point, Rel, Size, VAlignment};
 use crate::math::{
-    GlyphFragment, LayoutMath, MathContext, MathFragment, Scaled, VariantFragment,
+    scaled_font_size, GlyphFragment, LayoutMath, MathContext, MathFragment, Scaled,
+    VariantFragment,
 };
 use crate::utils::Get;
 
@@ -91,7 +92,7 @@ pub(super) fn stretch_fragment(
         glyph,
         stretch
             .unwrap_or(Rel::one())
-            .resolve(styles)
+            .at(scaled_font_size(ctx, styles))
             .relative_to(relative_to_size),
         short_fall,
         axis,

tests/ref/math-accent-sized-script.png

@@ -31,3 +31,7 @@ $ tilde(integral), tilde(integral)_a^b, tilde(integral_a^b) $
 --- math-accent-sized ---
 // Test accent size.
 $tilde(sum), tilde(sum, size: #50%), accent(H, hat, size: #200%)$
+
+--- math-accent-sized-script ---
+// Test accent size in script size.
+$tilde(U, size: #1.1em), x^tilde(U, size: #1.1em), sscript(tilde(U, size: #1.1em))$

tests/ref/math-spacing-script.png

@@ -49,6 +49,10 @@ $integral f(x) thin dif x$,
 // Both are weak, collide
 $integral f(x) #h(0.166em, weak: true)dif x$
 
+--- math-spacing-script ---
+// Test spacing in script size
+$x^(a #h(1em) b) + x^x^(a #h(1em) b) + sscript(a #h(1em) b)$
+
 --- math-spacing-ignorant ---
 // Test spacing with ignorant elements
 $#metadata(none) "text"$ \