Merge upstream/main into fix/update-without-prev-is-refused

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Pq7HyCHD1R3rywQBPCHXZA

crates/render/src/text.rs

@@ -175,6 +175,11 @@ impl PageText {
             .collect()
     }
 
+    /// Index of the first glyph whose box holds a view-space point: the text under the pointer.
+    pub fn glyph_at(&self, x: f32, y: f32) -> Option<usize> {
+        self.glyphs.iter().position(|g| x >= g.rect[0] && x <= g.rect[2] && y >= g.rect[1] && y <= g.rect[3])
+    }
+
     /// Index of the glyph nearest to a view-space point (for selection anchors).
     ///
     /// A glyph whose drawn em box (`quad`) holds the point wins. Skewed or turned text has bounding

crates/render/src/text/tests.rs

@@ -1965,3 +1965,18 @@ fn text_outside_the_crop_box_is_clipped() {
         assert!(text.is_empty(), "expected no glyphs on {crop:?}, got {:?}", text.plain_text());
     }
 }
+
+/// The glyph under a point is the first whose box holds it, edges included; between glyphs, none.
+#[test]
+fn the_glyph_at_a_point_is_the_first_whose_box_holds_it() {
+    let text = PageText {
+        glyphs: vec![em_box("a", 0.0, 0.0, 10.0, 10.0), em_box("b", 8.0, 0.0, 20.0, 10.0)],
+        line_of: vec![0, 0],
+        space_before: vec![false, false],
+    };
+    assert_eq!(text.glyph_at(5.0, 5.0), Some(0));
+    assert_eq!(text.glyph_at(9.0, 5.0), Some(0), "the first of overlapping boxes");
+    assert_eq!(text.glyph_at(20.0, 10.0), Some(1), "an edge is in");
+    assert_eq!(text.glyph_at(25.0, 5.0), None);
+    assert_eq!(PageText::default().glyph_at(0.0, 0.0), None);
+}