SENSORS

src/layout/ui.rs

@@ -1,5 +1,5 @@
 use crate::{
-    HashMap, Painter, Widget, WidgetId, WidgetLike,
+    HashMap, Painter, SenseCtx, UiRegion, Widget, WidgetId, WidgetLike,
     primitive::Primitives,
     util::{IDTracker, Id},
 };
@@ -13,6 +13,7 @@ pub struct Ui<Ctx> {
     base: Option<WidgetId>,
     widgets: Widgets<Ctx>,
     updates: Vec<WidgetId>,
+    sensors: Sensors<Ctx>,
     primitives: Primitives,
     full_redraw: bool,
 }
@@ -20,6 +21,27 @@ pub struct Ui<Ctx> {
 #[derive(Default)]
 pub struct Widgets<Ctx>(HashMap<Id, Box<dyn Widget<Ctx>>>);
 
+#[derive(Clone, Copy)]
+pub enum Sense {
+    Click,
+    Hover,
+}
+pub type Sensors<Ctx> = Vec<(SenseTrigger, Box<dyn SenseFn<Ctx>>)>;
+pub trait SenseFn_<Ctx> = Fn(&mut Ui<Ctx>, &mut Ctx) + 'static;
+pub type SenseShape = UiRegion;
+pub struct SenseTrigger {
+    pub shape: SenseShape,
+    pub sense: Sense,
+}
+pub trait SenseFn<Ctx>: SenseFn_<Ctx> {
+    fn box_clone(&self) -> Box<dyn SenseFn<Ctx>>;
+}
+impl<F: SenseFn_<Ctx> + Clone, Ctx> SenseFn<Ctx> for F {
+    fn box_clone(&self) -> Box<dyn SenseFn<Ctx>> {
+        Box::new(self.clone())
+    }
+}
+
 impl<Ctx> Ui<Ctx> {
     pub fn add<W: Widget<Ctx>, Tag>(
         &mut self,
@@ -67,13 +89,27 @@ impl<Ctx> Ui<Ctx> {
     where
         Ctx: 'static,
     {
-        let mut painter = Painter::new(&self.widgets, ctx);
+        self.sensors.clear();
+        let mut painter = Painter::new(&self.widgets, ctx, &mut self.sensors);
         if let Some(base) = &self.base {
             painter.draw(base);
         }
         self.primitives = painter.finish();
     }
 
+    pub fn run_sensors(&mut self, ctx: &mut Ctx)
+    where
+        Ctx: SenseCtx,
+    {
+        for (t, f) in self.sensors.iter().rev() {
+            if ctx.active(t) {
+                let f = f.as_ref().box_clone();
+                f(self, ctx);
+                return;
+            }
+        }
+    }
+
     pub fn update(&mut self, ctx: &mut Ctx) -> Option<&Primitives>
     where
         Ctx: 'static,
@@ -94,8 +130,6 @@ impl<Ctx> Ui<Ctx> {
     pub fn needs_redraw(&self) -> bool {
         self.full_redraw || !self.updates.is_empty()
     }
-
-    pub fn set_mouse_pos(&mut self) {}
 }
 
 impl<W: Widget<Ctx>, Ctx> Index<&WidgetId<W>> for Ui<Ctx> {
@@ -157,7 +191,8 @@ impl<Ctx> Default for Ui<Ctx> {
             widgets: Widgets::new(),
             updates: Default::default(),
             primitives: Default::default(),
-            full_redraw: Default::default(),
+            full_redraw: false,
+            sensors: Default::default(),
         }
     }
 }