Demos: ensure all use fun main() = application {

- Adjust some demo window sizes.
- Replace Random.double by Double.uniform
- Tweak some demos so screenshots look more interesting

orx-view-box/src/jvmDemo/kotlin/DemoProxyProgram02.kt

@@ -0,0 +1,64 @@
+import org.openrndr.*
+import org.openrndr.color.ColorRGBa
+import org.openrndr.extra.viewbox.ViewBox
+import org.openrndr.extra.viewbox.viewBox
+import org.openrndr.math.Vector2
+import kotlin.math.cos
+
+/**
+ * Demonstrates how to use two proxy programs and
+ * toggle between them by clicking the mouse.
+ *
+ * programA draws a circle and can be moved by pressing the
+ * arrow keys.
+ *
+ * programB draws a ring located at the current mouse
+ * position.
+ *
+ * Note that programA keeps listening to the key events
+ * even if programB is currently displayed.
+ */
+fun Program.programA() {
+    var pos = drawer.bounds.center
+    extend {
+        drawer.fill = ColorRGBa.PINK
+        drawer.circle(pos, cos(seconds) * 50.0 + 50.0)
+    }
+    keyboard.keyDown.listen {
+        when (it.key) {
+            KEY_ARROW_UP -> pos -= Vector2.UNIT_Y * 20.0
+            KEY_ARROW_DOWN -> pos += Vector2.UNIT_Y * 20.0
+            KEY_ARROW_LEFT -> pos -= Vector2.UNIT_X * 20.0
+            KEY_ARROW_RIGHT -> pos += Vector2.UNIT_X * 20.0
+        }
+    }
+}
+
+fun Program.programB() {
+    extend {
+        drawer.fill = ColorRGBa.TRANSPARENT
+        drawer.stroke = ColorRGBa.CYAN
+        drawer.strokeWeight = 50.0
+        drawer.circle(mouse.position, 200.0)
+    }
+}
+
+fun main() = application {
+    configure {
+        width = 720
+        height = 360
+    }
+    program {
+        val proxyBoxes = mutableListOf<ViewBox>()
+        proxyBoxes.add(viewBox(drawer.bounds).apply { programA() })
+        proxyBoxes.add(viewBox(drawer.bounds).apply { programB() })
+
+        var currentBox = 1
+        extend {
+            proxyBoxes[currentBox].draw()
+        }
+        mouse.buttonDown.listen {
+            currentBox = (currentBox + 1) % proxyBoxes.size
+        }
+    }
+}