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/DemoUpdate01.kt

@@ -1,30 +1,46 @@
 import org.openrndr.application
 import org.openrndr.extra.camera.Camera2D
 import org.openrndr.extra.viewbox.viewBox
+import org.openrndr.math.transforms.transform
 import org.openrndr.shape.Rectangle
 
-fun main() {
-    application {
-        configure {
-            width = 800
-            height = 800
-        }
-        program {
-            val vbx = viewBox(Rectangle(0.0, 0.0, 200.0, 200.0)) {
-                extend(Camera2D())
-                extend {
-                    drawer.rectangle(20.0, 20.0, 100.0, 100.0)
+/**
+ * Demonstrates how to create a viewBox with an interactive 2D camera and
+ * display it multiple times.
+ *
+ * Instead of calling the viewBox's `.draw()` method multiple times,
+ * we call its `.update()` method once, then draw its `.result`
+ * repeatedly, in a grid of 4 columns and 4 rows.
+ *
+ * The camera's initial rotation and scaling are specified as a transformation matrix.
+ * To control the camera use the mouse wheel and buttons on the top-left view.
+ */
+fun main() = application {
+    configure {
+        width = 720
+        height = 720
+    }
+    program {
+        val vbx = viewBox(Rectangle(0.0, 0.0, 200.0, 200.0)) {
+            extend(Camera2D()) {
+                // Set the initial view for the camera
+                view = transform {
+                    rotate(30.0)
+                    scale(2.0)
                 }
             }
-
             extend {
-                vbx.update()
-                for (j in 0 until 4) {
-                    for (i in 0 until 4) {
-                        drawer.image(vbx.result, j * 200.0, i * 200.0)
-                    }
+                drawer.rectangle(20.0, 20.0, 100.0, 100.0)
+            }
+        }
+
+        extend {
+            vbx.update()
+            for (j in 0 until 4) {
+                for (i in 0 until 4) {
+                    drawer.image(vbx.result, j * 200.0, i * 200.0)
                 }
             }
         }
     }
-}
+}