selector

src/widget/mod.rs

@@ -5,6 +5,7 @@ mod ptr;
 mod rect;
 mod text;
 mod trait_fns;
+mod selector;
 
 pub use image::*;
 pub use mask::*;
@@ -13,3 +14,4 @@ pub use ptr::*;
 pub use rect::*;
 pub use text::*;
 pub use trait_fns::*;
+pub use selector::*;

src/widget/selector.rs

@@ -0,0 +1,48 @@
+use std::hash::Hash;
+
+use iris_core::util::HashMap;
+
+use crate::prelude::*;
+
+pub struct WidgetSelector<T> {
+    current: (T, StrongWidget),
+    map: HashMap<T, StrongWidget>,
+}
+
+impl<T: Hash + Eq> WidgetSelector<T> {
+    pub fn new(key: T, widget: StrongWidget) -> Self {
+        Self {
+            current: (key, widget),
+            map: Default::default(),
+        }
+    }
+
+    pub fn set(&mut self, key: T, widget: StrongWidget) {
+        self.map.insert(key, widget);
+    }
+
+    pub fn select(&mut self, key: T) -> bool {
+        if let Some(val) = self.map.remove(&key) {
+            let mut new = (key, val);
+            std::mem::swap(&mut new, &mut self.current);
+            self.map.insert(new.0, new.1);
+            true
+        } else {
+            false
+        }
+    }
+}
+
+impl<T: 'static> Widget for WidgetSelector<T> {
+    fn draw(&mut self, painter: &mut Painter) {
+        painter.widget(&self.current.1);
+    }
+
+    fn desired_width(&mut self, ctx: &mut SizeCtx) -> Len {
+        ctx.width(&self.current.1)
+    }
+
+    fn desired_height(&mut self, ctx: &mut SizeCtx) -> Len {
+        ctx.height(&self.current.1)
+    }
+}