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()
+                        });
+                    }
                 });
             }
         }