[orx-shapes] Add Rectangle.intersection()

orx-shapes/src/commonMain/kotlin/primitives/RectangleIntersection.kt

@@ -0,0 +1,23 @@
+package org.openrndr.extra.shapes.primitives
+
+import org.openrndr.shape.Rectangle
+import kotlin.math.max
+import kotlin.math.min
+
+/**
+ * Find intersection of [this] and [other]
+ * @return a rectangle shaped intersection or [Rectangle.EMPTY] when the intersection is empty.
+ */
+fun Rectangle.intersection(other: Rectangle) : Rectangle = if (this.intersects(other)) {
+    val tn = this.normalized
+    val on = other.normalized
+
+    val left = max(tn.corner.x, on.corner.x)
+    val right = min(tn.corner.x + tn.width, on.corner.x + on.width)
+    val top = max(tn.corner.y, on.corner.y)
+    val bottom = min(tn.corner.y + tn.height, on.corner.y + on.height)
+
+    Rectangle(left, top, right - left, bottom - top)
+} else {
+    Rectangle.EMPTY
+}