Some minor fixes and additions

emigui/src/layout.rs

@@ -308,6 +308,10 @@ impl Region {
         self.available_space.y
     }
 
+    pub fn size(&self) -> Vec2 {
+        self.available_space
+    }
+
     pub fn direction(&self) -> Direction {
         self.dir
     }

emigui/src/math.rs

@@ -40,6 +40,14 @@ impl Vec2 {
     }
 }
 
+impl std::ops::Neg for Vec2 {
+    type Output = Vec2;
+
+    fn neg(self) -> Vec2 {
+        vec2(-self.x, -self.y)
+    }
+}
+
 impl std::ops::AddAssign for Vec2 {
     fn add_assign(&mut self, rhs: Vec2) {
         *self = Vec2 {

emigui/src/types.rs

@@ -83,7 +83,7 @@ pub struct Outline {
     pub color: Color,
 }
 
-#[derive(Clone, Debug, Serialize)] // TODO: copy
+#[derive(Clone, Debug, Serialize)]
 #[serde(rename_all = "snake_case", tag = "kind")]
 pub enum PaintCmd {
     Circle {

emigui/src/widgets.rs

@@ -247,7 +247,7 @@ impl Widget for RadioButton {
 // ----------------------------------------------------------------------------
 
 pub struct Slider<'a> {
-    get_set_value: Box<'a + FnMut(Option<f32>) -> f32>,
+    get_set_value: Box<dyn 'a + FnMut(Option<f32>) -> f32>,
     min: f32,
     max: f32,
     id: Option<Id>,