preparation

src/layout/sense.rs

@@ -1,3 +1,5 @@
+use std::any::Any;
+
 use crate::{
     layout::{Ui, UiRegion, Vec2, WidgetId},
     util::{HashMap, Id, bitflags},
@@ -42,15 +44,15 @@ pub struct SensorGroup {
     pub cursor: ActivationState,
     pub sensors: Vec<Sensor>,
 }
-pub trait SenseFn: FnMut(&mut Ui) + 'static {
-    fn box_clone(&self) -> Box<dyn SenseFn>;
-}
-impl<F: FnMut(&mut Ui) + 'static + Clone> SenseFn for F {
-    fn box_clone(&self) -> Box<dyn SenseFn> {
-        Box::new(self.clone())
-    }
+
+pub struct SenseCtx {
+    pub cursor: Vec2,
+    pub size: Vec2,
 }
 
+pub trait SenseFn: FnMut(&mut Ui, SenseCtx) + 'static {}
+impl<F: FnMut(&mut Ui, SenseCtx) + 'static> SenseFn for F {}
+
 impl Ui {
     pub fn add_sensor<W>(&mut self, id: &WidgetId<W>, f: Sensor) {
         self.sensor_map
@@ -72,7 +74,11 @@ impl Ui {
 
             for sensor in &mut group.sensors {
                 if should_run(sensor.senses, group.cursor, group.hover) {
-                    (sensor.f.box_clone())(self);
+                    let ctx = SenseCtx {
+                        cursor: cursor.pos - region.top_left,
+                        size: region.bot_right - region.top_left,
+                    };
+                    (sensor.f)(self, ctx);
                 }
             }
         }
@@ -132,21 +138,3 @@ impl ActivationState {
         }
     }
 }
-
-impl Clone for SensorGroup {
-    fn clone(&self) -> Self {
-        Self {
-            hover: self.hover,
-            cursor: self.cursor,
-            sensors: self.sensors.clone(),
-        }
-    }
-}
-impl Clone for Sensor {
-    fn clone(&self) -> Self {
-        Self {
-            senses: self.senses,
-            f: self.f.box_clone(),
-        }
-    }
-}