Merge pull request #5718 from dotCooCoo/fix/glyph-query-overflow-fallback

Glyphs: the Glyphs query reports the fallback glyph of an overflowing character

crates/engine/src/cmd/textedit.rs

@@ -1203,8 +1203,9 @@ fn own_glyph(
 /// The glyph of `face` drawn for the character `ch` at `bytes` of `t` when the character is shaped
 /// alone in the writing direction of `t` and the direction its paragraph sets it in, with the rest
 /// of its grapheme in the grapheme's own styles: the glyph of a character that is not laid out
-/// (overflowing text).
-fn shaped_alone(t: &TextObject, ch: char, bytes: &std::ops::Range<usize>, face: &vectorcraft_text::FontFace) -> Option<u32> {
+/// (overflowing text). Also the first glyph drawn for the character, which can be in a fallback
+/// face.
+fn shaped_alone(t: &TextObject, ch: char, bytes: &std::ops::Range<usize>, face: &vectorcraft_text::FontFace) -> (Option<u32>, Option<u32>) {
     use vectorcraft_doc::ParaDirection;
     let plain = t.plain_text();
     let end = edit::next_cluster(&plain, bytes.start).max(bytes.end);
@@ -1218,7 +1219,8 @@ fn shaped_alone(t: &TextObject, ch: char, bytes: &std::ops::Range<usize>, face:
     let rtl = vectorcraft_text::char_is_rtl(plain.get(start..stop).unwrap_or_default(), t.para_at(paragraph).direction, bytes.start - start);
     single.para.direction = Some(if rtl { ParaDirection::RightToLeft } else { ParaDirection::LeftToRight });
     let lay = vectorcraft_text::layout(vectorcraft_text::FontDb::global(), &single);
-    own_glyph(&single.plain_text(), &lay, ch, &(0..bytes.len()), face).flatten()
+    let first = lay.glyphs.iter().find(|g| g.byte == 0 && g.len > 0).map(|g| g.gid);
+    (own_glyph(&single.plain_text(), &lay, ch, &(0..bytes.len()), face).flatten(), first)
 }
 
 fn set_glyph_alternate(s: &mut Session, p: &Value) -> Result<Value> {
@@ -1253,7 +1255,7 @@ fn set_glyph_alternate(s: &mut Session, p: &Value) -> Result<Value> {
         let mut probe = t.clone();
         edit::style_range(&mut probe.runs, bytes.start, bytes.end, |st| st.glyph_alternate = None);
         let lay = vectorcraft_text::layout(vectorcraft_text::FontDb::global(), &probe);
-        own_glyph(&plain, &lay, ch, &bytes, &face).unwrap_or_else(|| shaped_alone(&probe, ch, &bytes, &face))
+        own_glyph(&plain, &lay, ch, &bytes, &face).unwrap_or_else(|| shaped_alone(&probe, ch, &bytes, &face).0)
     });
     let substituted = unchosen.is_some_and(|g| g != default);
     let choice = match gid.filter(|g| *g != default || substituted) {
@@ -1304,10 +1306,14 @@ fn glyph_alternates(s: &mut Session, p: &Value) -> Result<Value> {
     let lay = vectorcraft_text::layout(vectorcraft_text::FontDb::global(), &t);
     let first = lay.glyphs.iter().find(|g| g.byte <= bytes.start && bytes.start < g.byte.saturating_add(g.len)).map(|g| g.gid);
     // A character that is not laid out (overflowing text) reports the glyph it is drawn with when
-    // it is shaped alone, as `text.setGlyphAlternate` finds it.
+    // it is shaped alone, as `text.setGlyphAlternate` finds it; a fallback face's glyph when it is
+    // drawn in one.
     let chosen = match own_glyph(&t.plain_text(), &lay, ch, &bytes, &face) {
         Some(own) => own.or(first),
-        None => shaped_alone(&t, ch, &bytes, &face),
+        None => {
+            let (own, first) = shaped_alone(&t, ch, &bytes, &face);
+            own.or(first)
+        }
     }
     .unwrap_or(default);
     let alternates: Vec<Value> = face.alternates(ch).iter().map(|a| json!({"gid": a.gid, "feature": String::from_utf8_lossy(&a.feature)})).collect();

crates/engine/src/tests/textedit.rs

@@ -2793,4 +2793,10 @@ fn glyph_alternates_query_reports_the_fallback_glyph_that_is_drawn() {
     let query = s.execute("text.glyphAlternates", &json!({"id": id.0, "start": 0})).unwrap();
     assert_eq!(query["chosen"], json!(glyph.gid), "the query reports the visible fallback glyph");
     assert!(query["alternates"].as_array().unwrap().is_empty());
+
+    let area = json!({"x": 0, "y": 300, "text": ch.to_string(), "font": alternates_family(true), "area": {"width": 200, "height": 2}});
+    let boxed = NodeId(s.execute("text.create", &area).unwrap()["id"].as_u64().unwrap());
+    assert!(vectorcraft_text::layout(db, &obj(&s, boxed)).glyphs.is_empty(), "the text overflows");
+    let query = s.execute("text.glyphAlternates", &json!({"id": boxed.0, "start": 0})).unwrap();
+    assert_eq!(query["chosen"], json!(glyph.gid), "an overflowing character reports the fallback glyph it is drawn with");
 }