Clip behavior card labels to their bounds

crates/oa-desktop/src/behavior.rs

@@ -1069,6 +1069,17 @@ struct BoxItem {
     detail: String,
     marker: Option<Kind>,
 }
+fn box_text_clip(rect: Rectangle, scale: f32, viewport: Size) -> Option<Rectangle> {
+    if !scale.is_finite() || scale <= 0. || rect.width <= 20. || rect.height <= 16. {
+        return None;
+    }
+    Rectangle::new(
+        Point::new((rect.x + 10.) * scale, (rect.y + 8.) * scale),
+        Size::new((rect.width - 20.) * scale, (rect.height - 16.) * scale),
+    )
+    .intersection(&Rectangle::new(Point::ORIGIN, viewport))
+}
+
 struct Line {
     id: Id,
     points: Vec<Point>,
@@ -2134,24 +2145,31 @@ impl canvas::Program<Message> for Scene {
             }
         }
         for b in &self.boxes {
-            f.fill_text(Text {
-                content: short(&b.title, ((b.rect.width - 25.) / 7.) as usize),
-                position: Point::new(b.rect.x + 12., b.rect.y + 12.),
-                size: 13.into(),
-                color: if b.id == self.selected {
-                    style::TEAL
-                } else {
-                    style::INK
-                },
-                ..Default::default()
-            });
-            if !b.detail.is_empty() {
-                f.fill_text(Text {
-                    content: short(&b.detail, ((b.rect.width - 25.) / 6.) as usize),
-                    position: Point::new(b.rect.x + 12., b.rect.y + 39.),
-                    size: 11.into(),
-                    color: style::MUTED,
-                    ..Default::default()
+            if let Some(clip) = box_text_clip(b.rect, self.scale, f.size()) {
+                // Clipped child frames start with an identity transform. Match
+                // the card's scale explicitly, as for lifecycle Create labels.
+                f.with_clip(clip, |label| {
+                    label.scale(self.scale);
+                    label.fill_text(Text {
+                        content: short(&b.title, ((b.rect.width - 25.) / 7.) as usize),
+                        position: Point::new(b.rect.x + 12., b.rect.y + 12.),
+                        size: 13.into(),
+                        color: if b.id == self.selected {
+                            style::TEAL
+                        } else {
+                            style::INK
+                        },
+                        ..Default::default()
+                    });
+                    if !b.detail.is_empty() {
+                        label.fill_text(Text {
+                            content: short(&b.detail, ((b.rect.width - 25.) / 6.) as usize),
+                            position: Point::new(b.rect.x + 12., b.rect.y + 39.),
+                            size: 11.into(),
+                            color: style::MUTED,
+                            ..Default::default()
+                        });
+                    }
                 });
             }
         }

crates/oa-desktop/src/behavior/scenario_lifecycle/render_tests.rs

@@ -173,6 +173,116 @@ fn intervals(scene: &Scene, lifeline: Id, scope: Id) -> Vec<(f32, f32, Life)> {
         .collect()
 }
 
+#[test]
+fn real_scene_long_header_title_and_detail_keep_names_and_have_bounded_clips() {
+    for layer in [Layer::Oa, Layer::Sa] {
+        for name in [
+            "W".repeat(18),
+            "界".repeat(24),
+            "e\u{301}".repeat(24),
+            "👩\u{200d}🔧".repeat(12),
+        ] {
+            let mut f = Fixture::new(layer);
+            f.project.elements.get_mut(&f.receiver).unwrap().name = name.clone();
+            f.project.elements.get_mut(&f.work).unwrap().name = name.clone();
+            let scene = f.scene();
+            let header = scene.boxes.iter().find(|b| b.id == f.receiver).unwrap();
+            assert_eq!(header.title, format!("Lane · {name}"));
+            assert_eq!(header.detail, name);
+            assert_eq!(header.rect.size(), Size::new(204., 70.));
+            assert_eq!(scene.hit(header.rect.center()), Some(f.receiver));
+            // Scroll offset is handled by the existing outer canvas/scrollable;
+            // these are the local drawing frame's coordinates, not screen input.
+            for scale in [0.05, 0.5, 0.512, 0.64, 0.8, 1., 1.953125, 2.] {
+                let clip =
+                    crate::behavior::box_text_clip(header.rect, scale, Size::new(2000., 2000.))
+                        .unwrap();
+                let world = Rectangle::new(
+                    Point::new(clip.x / scale, clip.y / scale),
+                    Size::new(clip.width / scale, clip.height / scale),
+                );
+                assert!((world.x - header.rect.x - 10.).abs() < 0.001);
+                assert!((world.y - header.rect.y - 8.).abs() < 0.001);
+                assert!((world.width - 184.).abs() < 0.001);
+                assert!((world.height - 54.).abs() < 0.001);
+                assert!(header.rect.contains(world.position()));
+                assert!(
+                    header
+                        .rect
+                        .contains(Point::new(world.x + world.width, world.y + world.height,))
+                );
+            }
+        }
+    }
+}
+
+#[test]
+fn box_text_clip_intersects_parent_viewport_and_rejects_empty_interiors() {
+    use crate::behavior::box_text_clip;
+    let card = Rectangle::new(Point::new(100., 200.), Size::new(204., 70.));
+    assert_eq!(
+        box_text_clip(card, 2., Size::new(300., 500.)),
+        Some(Rectangle::new(Point::new(220., 416.), Size::new(80., 84.)))
+    );
+    assert_eq!(
+        box_text_clip(
+            Rectangle::new(Point::new(-20., -10.), card.size()),
+            2.,
+            Size::new(300., 500.),
+        ),
+        Some(Rectangle::new(Point::ORIGIN, Size::new(300., 104.)))
+    );
+    for viewport in [Size::new(200., 500.), Size::new(300., 400.), Size::ZERO] {
+        assert_eq!(box_text_clip(card, 2., viewport), None);
+    }
+    for scale in [0., -1., f32::NAN, f32::INFINITY] {
+        assert_eq!(box_text_clip(card, scale, Size::new(1000., 1000.)), None);
+    }
+    for size in [Size::new(20., 70.), Size::new(204., 16.), Size::ZERO] {
+        assert_eq!(
+            box_text_clip(Rectangle::new(Point::ORIGIN, size), 1., card.size()),
+            None
+        );
+    }
+}
+
+#[test]
+fn real_scene_wide_latin_header_exceeds_old_character_budget() {
+    use iced::advanced::text::{self, Paragraph as _};
+    let mut f = Fixture::new(Layer::Oa);
+    f.project.elements.get_mut(&f.receiver).unwrap().name = "W".repeat(18);
+    f.project.elements.get_mut(&f.work).unwrap().name = "W".repeat(24);
+    let scene = f.scene();
+    let header = scene.boxes.iter().find(|b| b.id == f.receiver).unwrap();
+    for (content, size, divisor) in [(&header.title, 13., 7.), (&header.detail, 11., 6.)] {
+        let label = iced::widget::canvas::Text {
+            content: crate::views::short(content, ((header.rect.width - 25.) / divisor) as usize),
+            size: size.into(),
+            ..Default::default()
+        };
+        // Use the same real paragraph/font/shaping defaults as canvas Text.
+        // The native defect survives short(): glyph width, not scalar count,
+        // is what exceeds the card. This is a font witness, not a pixel gate.
+        let paragraph = <iced::Renderer as text::Renderer>::Paragraph::with_text(text::Text {
+            content: label.content.as_str(),
+            bounds: Size::INFINITE,
+            size: label.size,
+            line_height: label.line_height,
+            font: label.font,
+            align_x: label.align_x,
+            align_y: label.align_y,
+            shaping: label.shaping,
+            wrapping: text::Wrapping::default(),
+        });
+        let old_available = header.rect.width - 12.;
+        assert!(
+            paragraph.min_width() > old_available,
+            "wide glyph fixture must overflow the old unbounded card: {} <= {old_available}",
+            paragraph.min_width()
+        );
+    }
+}
+
 #[test]
 fn birth_label_clip_keeps_padded_world_bounds_at_each_scene_scale() {
     let capsule = Rectangle::new(Point::new(100., 200.), Size::new(140., 28.));