Treat italics correction differently

library/src/math/attach.rs

@@ -192,11 +192,8 @@ fn scripts(
     }
 
     let italics = base.italics_correction();
+    let sup_delta = Abs::zero();
     let sub_delta = -italics;
-    let sup_delta = match base.class() {
-        Some(MathClass::Large) => Abs::zero(),
-        _ => italics,
-    };
 
     let mut width = Abs::zero();
     let mut ascent = base.ascent();

library/src/math/fragment.rs

@@ -152,13 +152,19 @@ impl GlyphFragment {
             x_max: 0,
             y_max: 0,
         });
+
+        let mut width = advance.scaled(ctx);
+        if !is_extended_shape(ctx, id) {
+            width += italics;
+        }
+
         Self {
             id,
             c,
             lang: ctx.styles().get(TextNode::LANG),
             fill: ctx.styles().get(TextNode::FILL),
             font_size: ctx.size,
-            width: advance.scaled(ctx),
+            width,
             ascent: bbox.y_max.scaled(ctx),
             descent: -bbox.y_min.scaled(ctx),
             italics_correction: italics,
@@ -249,6 +255,15 @@ fn italics_correction(ctx: &MathContext, id: GlyphId) -> Option<Abs> {
     Some(ctx.table.glyph_info?.italic_corrections?.get(id)?.scaled(ctx))
 }
 
+/// Look up the italics correction for a glyph.
+fn is_extended_shape(ctx: &MathContext, id: GlyphId) -> bool {
+    ctx.table
+        .glyph_info
+        .and_then(|info| info.extended_shapes)
+        .and_then(|info| info.get(id))
+        .is_some()
+}
+
 /// Look up a kerning value at a specific corner and height.
 ///
 /// This can be integrated once we've found a font that actually provides this

library/src/math/row.rs

@@ -59,10 +59,6 @@ impl MathRow {
             }
 
             let mut amount = Abs::zero();
-            if let MathFragment::Glyph(glyph) = *prev {
-                amount += glyph.italics_correction;
-            }
-
             amount += spacing(prev, &fragment, style, space, space_width).at(font_size);
 
             if !amount.is_zero() {