Plot items now have optional id which is returned in the plot's respo…

…nse when hovered (#3920) This allows users to check which item the user interacts with in the plot. https://github.com/emilk/egui/assets/1220815/1a174b38-8414-49be-a802-d187cd93d154 --------- Co-authored-by: Emil Ernerfeldt <[email protected]>
emilk · Jan 30, 2024 · ca513ce · ca513ce
1 parent 945a69d
commit ca513ce
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Showing 4 changed files with 180 additions and 18 deletions.
diff --git a/crates/egui_demo_lib/src/demo/plot_demo.rs b/crates/egui_demo_lib/src/demo/plot_demo.rs
@@ -791,8 +791,28 @@ impl InteractionDemo {
         let PlotResponse {
             response,
             inner: (screen_pos, pointer_coordinate, pointer_coordinate_drag_delta, bounds, hovered),
+            hovered_plot_item,
             ..
         } = plot.show(ui, |plot_ui| {
+            plot_ui.line(
+                Line::new(PlotPoints::from_explicit_callback(
+                    move |x| x.sin(),
+                    ..,
+                    100,
+                ))
+                .color(Color32::RED)
+                .id(egui::Id::new("sin")),
+            );
+            plot_ui.line(
+                Line::new(PlotPoints::from_explicit_callback(
+                    move |x| x.cos(),
+                    ..,
+                    100,
+                ))
+                .color(Color32::BLUE)
+                .id(egui::Id::new("cos")),
+            );
+
             (
                 plot_ui.screen_from_plot(PlotPoint::new(0.0, 0.0)),
                 plot_ui.pointer_coordinate(),
@@ -824,6 +844,15 @@ impl InteractionDemo {
         );
         ui.label(format!("pointer coordinate drag delta: {coordinate_text}"));
 
+        let hovered_item = if hovered_plot_item == Some(egui::Id::new("sin")) {
+            "red sin"
+        } else if hovered_plot_item == Some(egui::Id::new("cos")) {
+            "blue cos"
+        } else {
+            "none"
+        };
+        ui.label(format!("hovered plot item: {hovered_item}"));
+
         response
     }
 }