typography and documents: an exported formula frames its outlined text; rendered modes have no source selection

src/typography/math.rs

@@ -125,13 +125,20 @@ pub fn formula_svg(source: &str, display: bool) -> Result<String, MathError> {
         font: 1600,
         scale: 100,
     };
+    let (svg, width, height) = laid(&formula)?;
     // RaTeX writes text where it has no outline.
-    let (svg, _) = svg(&formula)?;
-    crate::documents::flatten(&svg).map_err(MathError::said)
+    let outlined = crate::documents::flatten(&svg).map_err(MathError::said)?;
+    framed(&outlined, width, height).map(|(svg, _)| svg)
 }
 
 /// The formula as outlined SVG holding all ink; its size.
 fn svg(formula: &Formula) -> Result<(String, Size<Pixels>), MathError> {
+    let (svg, width, height) = laid(formula)?;
+    framed(&svg, width, height)
+}
+
+/// RaTeX's SVG and the layout box's width and height.
+fn laid(formula: &Formula) -> Result<(String, f32, f32), MathError> {
     let ast = parsed(&formula.source)?;
     let [r, g, b, a] = formula
         .rgba
@@ -144,7 +151,7 @@ fn svg(formula: &Formula) -> Result<(String, Size<Pixels>), MathError> {
         })
         .with_color(Color::new(r, g, b, a));
     let font = f64::from(formula.font) / 100.0;
-    let laid = guarded(|| {
+    let typeset = guarded(|| {
         let list = to_display_list(&layout(&ast, &options));
         let svg = render_to_svg(
             &list,
@@ -158,8 +165,8 @@ fn svg(formula: &Formula) -> Result<(String, Size<Pixels>), MathError> {
         );
         (list.width * font, (list.height + list.depth) * font, svg)
     })?;
-    let (width, height, svg) = laid;
-    framed(&svg, width as f32, height as f32)
+    let (width, height, svg) = typeset;
+    Ok((svg, width as f32, height as f32))
 }
 
 /// Runs RaTeX's layout; a panic becomes an error.

src/typography/math/tests.rs

@@ -193,3 +193,21 @@ fn an_exported_formula_outlines_its_text_or_says_why() {
     let why = formula_svg("\\text{\u{F0000}}", false).expect_err("no font");
     assert!(why.to_string().contains("font"), "{why}");
 }
+
+#[test]
+fn an_exported_formula_frames_its_outlined_text() {
+    // Wide or tall faces from the system, where fonts have them.
+    for source in [r"\text{한글}", r"\text{𓀀} + x"] {
+        let Ok(svg) = formula_svg(source, false) else {
+            continue;
+        };
+        let tree =
+            usvg::Tree::from_data(svg.as_bytes(), &usvg::Options::default()).expect("parses");
+        let (ink, shape) = (tree.root().abs_stroke_bounding_box(), tree.size());
+        let inside = ink.left() >= -0.01
+            && ink.top() >= -0.01
+            && ink.right() <= shape.width() + 0.01
+            && ink.bottom() <= shape.height() + 0.01;
+        assert!(inside, "{source}: {ink:?} in {shape:?}");
+    }
+}