Merge main into feat/live-rasterize-effect

crates/render/src/lib.rs

@@ -136,6 +136,10 @@ pub struct RenderOptions {
     pub mask_view: Option<NodeId>,
     /// Screen view: highlight substituted fonts and glyphs as Document Setup asks.
     pub highlight_substitutions: bool,
+    /// Screen view: Preferences › Type › Highlight Alternate Glyphs. Pink behind glyphs OpenType
+    /// features substituted (ligatures, contextual forms), not Document Setup's missing-glyph
+    /// highlights.
+    pub highlight_alternate_glyphs: bool,
     /// Edge smoothing (raster export option).
     pub anti_alias: AntiAlias,
     /// Screen view: placed documents draw from cached bitmaps made in the background (see
@@ -240,6 +244,7 @@ impl Default for RenderOptions {
             guide: ([0x4a, 0xd8, 0xff], false),
             mask_view: None,
             highlight_substitutions: false,
+            highlight_alternate_glyphs: false,
             anti_alias: AntiAlias::Art,
             progressive_placed: false,
             trace_views: false,
@@ -1802,8 +1807,11 @@ impl Renderer {
         }
         if f.opts.highlight_substitutions {
             let setup = &f.doc.setup;
-            for (on, path) in [(setup.highlight_substituted_fonts, &g.substituted_fonts), (setup.highlight_substituted_glyphs, &g.substituted_glyphs)]
-            {
+            for (on, path) in [
+                (setup.highlight_substituted_fonts, &g.substituted_fonts),
+                (setup.highlight_substituted_glyphs, &g.substituted_glyphs),
+                (f.opts.highlight_alternate_glyphs, &g.alternate_glyphs),
+            ] {
                 if on && !path.elements().is_empty() {
                     ctx.set_transform(xf);
                     ctx.set_fill_rule(peniko::Fill::NonZero);
@@ -2231,6 +2239,9 @@ struct TextGeom {
     /// font lacks (drawn from a fallback font): Document Setup's substitution highlights.
     substituted_fonts: BezPath,
     substituted_glyphs: BezPath,
+    /// Boxes of glyphs OpenType features substituted (ligatures, contextual forms): Preferences ›
+    /// Highlight Alternate Glyphs.
+    alternate_glyphs: BezPath,
     /// Inline graphics placed by the layout.
     inlines: Vec<vectorcraft_text::InlineGlyph>,
 }
@@ -2256,12 +2267,18 @@ impl TextGeom {
     /// Approximate heap bytes, for the cache's budget.
     fn bytes(&self) -> usize {
         size_of::<Self>()
-            + [&self.all, &self.substituted_fonts, &self.substituted_glyphs].into_iter().map(lru::path_bytes).sum::<usize>()
+            + [&self.all, &self.substituted_fonts, &self.substituted_glyphs, &self.alternate_glyphs].into_iter().map(lru::path_bytes).sum::<usize>()
             + self.spans.len() * size_of::<(usize, usize, usize)>()
             + self.inlines.len() * size_of::<vectorcraft_text::InlineGlyph>()
     }
 }
 
+/// OpenType-substituted form: a ligature (several source characters → one glyph) or a glyph whose
+/// id is not the face's cmap mapping for its first character (contextual / stylistic alternate).
+pub(crate) fn is_opentype_alternate(nominal_gid: u32, shaped_gid: u32, cluster_chars: usize) -> bool {
+    shaped_gid != 0 && (cluster_chars > 1 || shaped_gid != nominal_gid)
+}
+
 fn text_geom(t: &TextObject) -> TextGeom {
     text_geom_snapped(t, None)
 }
@@ -2301,30 +2318,39 @@ fn text_geom_snapped(t: &TextObject, snap: Option<Affine>) -> TextGeom {
             None => (true, None),
         })
         .collect();
-    let (mut substituted_fonts, mut substituted_glyphs) = (BezPath::new(), BezPath::new());
+    let (mut substituted_fonts, mut substituted_glyphs, mut alternate_glyphs) = (BezPath::new(), BezPath::new(), BezPath::new());
+    let plain = t.plain_text();
     for g in &layout.glyphs {
         push(&mut all, g.run, &g.outline);
         let Some(&(missing, face)) = faces.get(g.run) else { continue };
-        let target = if missing {
-            &mut substituted_fonts
-        } else if face.is_some_and(|f| f != g.font_id) {
-            &mut substituted_glyphs
-        } else {
-            continue;
-        };
         let Some(line) = layout.lines.get(g.line) else { continue };
         let mut cell = Rect::new(g.origin.x, g.origin.y - line.ascent, g.origin.x + g.advance, g.origin.y + line.descent).to_path(0.1);
         cell.apply_affine(Affine::rotate_about(g.angle, g.origin));
-        target.extend(cell.iter());
+        if missing {
+            substituted_fonts.extend(cell.iter());
+            continue;
+        }
+        if face.is_some_and(|f| f != g.font_id) {
+            substituted_glyphs.extend(cell.iter());
+            continue;
+        }
+        // Same face: OpenType may have swapped the glyph (liga, calt, …).
+        let Some(cluster) = plain.get(g.byte..g.byte.saturating_add(g.len)) else { continue };
+        let cluster_chars = cluster.chars().count();
+        let Some(first) = cluster.chars().next() else { continue };
+        let nominal = db.face_by_id(g.font_id).map(|f| f.glyph_for(first)).unwrap_or(0);
+        if is_opentype_alternate(nominal, g.gid, cluster_chars) {
+            alternate_glyphs.extend(cell.iter());
+        }
     }
     // Underline and strikethrough bars, painted as their run's type is (#847).
     for (run, bar) in vectorcraft_text::decorations(&layout, db, t) {
         push(&mut all, run, &bar);
     }
-    TextGeom { all, spans, bounds: layout.bounds, substituted_fonts, substituted_glyphs, inlines: layout.inlines }
+    TextGeom { all, spans, bounds: layout.bounds, substituted_fonts, substituted_glyphs, alternate_glyphs, inlines: layout.inlines }
 }
 
-/// Document Setup's highlight behind substituted fonts and glyphs (screen only).
+/// Document Setup's and Preferences › Highlight Alternate Glyphs pink (screen only).
 const SUBSTITUTED: peniko::Color = peniko::Color::from_rgba8(255, 120, 190, 110);
 /// The pixel size of `region` rendered at `scale` pixels per point (at least 1×1).
 pub fn region_pixels(region: Rect, scale: f64) -> (u32, u32) {
@@ -2380,6 +2406,8 @@ mod tests;
 #[cfg(test)]
 mod tests_adjust;
 #[cfg(test)]
+mod tests_alternate;
+#[cfg(test)]
 mod tests_blend;
 #[cfg(test)]
 mod tests_charstroke;

crates/render/src/tests_alternate.rs

@@ -0,0 +1,42 @@
+//! Preferences › Type › Highlight Alternate Glyphs (#394): OpenType substitutions get a pink
+//! cell behind them on screen when the preference is on.
+
+use super::*;
+
+#[test]
+fn is_opentype_alternate_marks_ligatures_and_forms() {
+    assert!(is_opentype_alternate(100, 100, 2), "ligature cluster");
+    assert!(is_opentype_alternate(50, 99, 1), "contextual / stylistic form");
+    assert!(!is_opentype_alternate(50, 50, 1), "nominal cmap glyph");
+    assert!(!is_opentype_alternate(50, 0, 2), "missing glyph");
+}
+
+#[test]
+fn highlight_alternate_glyphs_paints_pink_behind_a_ligature() {
+    use vectorcraft_doc::text::{CharStyle, TextObject};
+    use vectorcraft_doc::{Node, NodeKind};
+    use vectorcraft_geom::Point;
+
+    // Source Serif 4 ships with standard ligatures for "fi".
+    let mut d = Document::new(200.0, 100.0);
+    let style = CharStyle { size: 48.0, font_family: "Source Serif 4".into(), ..Default::default() };
+    let mut n = Node::new(NodeId(0), NodeKind::Text(Box::new(TextObject::point(Point::new(20.0, 70.0), "fi", style))));
+    n.id = d.alloc_id();
+    let l = d.layers[0].id;
+    d.insert(Some(l), 0, n).unwrap();
+
+    let off = RenderOptions {
+        background: Some([255, 255, 255, 255]),
+        highlight_substitutions: true,
+        highlight_alternate_glyphs: false,
+        ..Default::default()
+    };
+    let on = RenderOptions { highlight_alternate_glyphs: true, ..off.clone() };
+    let mut r = Renderer::new();
+    let without = r.render(&d, 200, 100, Affine::IDENTITY, &off);
+    let with = r.render(&d, 200, 100, Affine::IDENTITY, &on);
+    assert_ne!(without.pixels, with.pixels, "the preference changes the frame");
+    // Pink SUBSTITUTED = (255, 120, 190) at alpha 110, blended over white / ink.
+    let pinkish = with.pixels.chunks(4).filter(|p| p[0] > 200 && p[1] < 180 && p[2] > 150 && p[2] < 230).count();
+    assert!(pinkish > 10, "pink highlight cells behind the ligature ({pinkish} pixels)");
+}