Vertically center non-math content in math by default

library/src/math/mod.rs

@@ -294,7 +294,11 @@ impl LayoutMath for Content {
             return node.layout_math(ctx);
         }
 
-        let frame = ctx.layout_content(self)?;
+        let mut frame = ctx.layout_content(self)?;
+        if !frame.has_baseline() {
+            let axis = scaled!(ctx, axis_height);
+            frame.set_baseline(frame.height() / 2.0 + axis);
+        }
         ctx.push(FrameFragment::new(ctx, frame).with_spaced(true));
 
         Ok(())

src/doc.rs

@@ -85,6 +85,11 @@ impl Frame {
         self.baseline.unwrap_or(self.size.y)
     }
 
+    /// Whether the frame has a non-default baseline.
+    pub fn has_baseline(&mut self) -> bool {
+        self.baseline.is_some()
+    }
+
     /// Set the frame's baseline from the top.
     pub fn set_baseline(&mut self, baseline: Abs) {
         self.baseline = Some(baseline);

tests/typ/math/content.typ

@@ -6,9 +6,9 @@
 $ sum_(i=#emoji.apple)^#emoji.apple.red i + monkey/2 $
 
 ---
-// Test table above fraction.
-$ x := #table(columns: 2)[x][y]/mat(1, 2, 3) $
-
+// Test tables.
+$ x := #table(columns: 2)[x][y]/mat(1, 2, 3)
+     = #table[A][B][C] $
 ---
 // Test non-formula math directly in content.
 #math.attach($a$, top: [b])