perf(canvas): avoid select label allocations

crates/op-editor-ui/src/widgets/canvas_viewport_widget.rs

@@ -171,13 +171,13 @@ fn paint_select(cx: &mut PaintCx<'_>, node: &SceneNode, w: &SceneWidget, r: Rect
         Some(text) => Some((text, TEXT_VALUE)),
         None => w
             .placeholder
-            .clone()
+            .as_deref()
             .filter(|s| !s.is_empty())
             .map(|t| (t, TEXT_MUTED)),
     };
     if let Some((text, color)) = label {
         let fs = 14.0 * zoom;
-        draw_label(cx, &text, color, x + 8.0 * zoom, y + (h - fs) / 2.0, fs);
+        draw_label(cx, text, color, x + 8.0 * zoom, y + (h - fs) / 2.0, fs);
     }
     paint_chevron(cx, x + ww - 20.0 * zoom, y + h / 2.0, zoom);
 }
@@ -351,12 +351,12 @@ fn range_fraction(value: Option<f32>, min: f32, max: f32) -> f32 {
 }
 
 /// Look up a select / radio option's display label by its `value`.
-fn option_label(w: &SceneWidget, value: &str) -> Option<String> {
+pub(crate) fn option_label<'a>(w: &'a SceneWidget, value: &str) -> Option<&'a str> {
     w.options.iter().find(|o| o.value == value).map(|o| {
         if o.label.is_empty() {
-            o.value.clone()
+            o.value.as_str()
         } else {
-            o.label.clone()
+            o.label.as_str()
         }
     })
 }

crates/op-editor-ui/src/widgets/canvas_viewport_widget_tests.rs

@@ -3,7 +3,7 @@
 //! design surface (track + knob, box + check, bar, chevron, …).
 
 use crate::layout_scene::{NodeKind, SceneNode, SceneWidget, SceneWidgetOption};
-use crate::widgets::canvas_viewport_widget::paint_widget_visual;
+use crate::widgets::canvas_viewport_widget::{option_label, paint_widget_visual};
 use crate::widgets::PaintCx;
 use crate::{Color, ImageDrawMode, Point2D, Rect, RenderBackend, TextLayout};
 
@@ -309,6 +309,31 @@ fn select_empty_paints_placeholder() {
     );
 }
 
+#[test]
+fn select_option_label_borrows_matching_option_text() {
+    let widget = SceneWidget {
+        value_str: Some("pro".into()),
+        options: vec![
+            SceneWidgetOption {
+                value: "basic".into(),
+                label: "Basic".into(),
+            },
+            SceneWidgetOption {
+                value: "pro".into(),
+                label: "Pro Plan".into(),
+            },
+        ],
+        ..Default::default()
+    };
+
+    let label = option_label(&widget, "pro").expect("selected label");
+
+    assert!(std::ptr::eq(
+        label.as_ptr(),
+        widget.options[1].label.as_ptr()
+    ));
+}
+
 #[test]
 fn radio_group_paints_circle_and_dot_for_selected() {
     let rect = Rect::xywh(0.0, 0.0, 120.0, 56.0);