Draft (very) basic incremental rendering for iced_tiny_skia

core/src/rectangle.rs

@@ -100,6 +100,30 @@ impl Rectangle<f32> {
         }
     }
 
+    /// Returns whether the [`Rectangle`] intersects with the given one.
+    pub fn intersects(&self, other: &Self) -> bool {
+        self.intersection(other).is_some()
+    }
+
+    /// Computes the union with the given [`Rectangle`].
+    pub fn union(&self, other: &Self) -> Self {
+        let x = self.x.min(other.x);
+        let y = self.y.min(other.y);
+
+        let lower_right_x = (self.x + self.width).max(other.x + other.width);
+        let lower_right_y = (self.y + self.height).max(other.y + other.height);
+
+        let width = lower_right_x - x;
+        let height = lower_right_y - y;
+
+        Rectangle {
+            x,
+            y,
+            width,
+            height,
+        }
+    }
+
     /// Snaps the [`Rectangle`] to __unsigned__ integer coordinates.
     pub fn snap(self) -> Rectangle<u32> {
         Rectangle {
@@ -109,6 +133,16 @@ impl Rectangle<f32> {
             height: self.height as u32,
         }
     }
+
+    /// Expands the [`Rectangle`] a given amount.
+    pub fn expand(self, amount: f32) -> Self {
+        Self {
+            x: self.x - amount,
+            y: self.y - amount,
+            width: self.width + amount * 2.0,
+            height: self.height + amount * 2.0,
+        }
+    }
 }
 
 impl std::ops::Mul<f32> for Rectangle<f32> {