[orx-gui] Add visible property to Gui

orx-gui/src/demo/kotlin/DemoHide01.kt

@@ -0,0 +1,57 @@
+import org.openrndr.application
+import org.openrndr.color.ColorRGBa
+import org.openrndr.extensions.SingleScreenshot
+import org.openrndr.extra.gui.GUI
+import org.openrndr.extra.parameters.*
+import org.openrndr.math.Vector2
+import org.openrndr.shape.Circle
+
+/**
+ * A simple demonstration of a GUI for drawing some circles
+ */
+fun main() = application {
+    program {
+        // -- this block is for automation purposes only
+        if (System.getProperty("takeScreenshot") == "true") {
+            extend(SingleScreenshot()) {
+                this.outputFile = System.getProperty("screenshotPath")
+            }
+        }
+
+        val gui = GUI()
+        gui.compartmentsCollapsedByDefault = false
+
+
+        val settings = @Description("Settings") object {
+            @DoubleParameter("radius", 0.0, 100.0)
+            var radius = 50.0
+
+            @Vector2Parameter("position", 0.0, 1.0)
+            var position = Vector2(0.6, 0.5)
+
+            @ColorParameter("color")
+            var color = ColorRGBa.PINK
+
+            @DoubleListParameter("radii", 5.0, 30.0)
+            var radii = mutableListOf(5.0, 6.0, 8.0, 14.0, 20.0, 30.0)
+        }
+        gui.add(settings)
+        extend(gui)
+
+        // note we can only change the visibility after the extend
+        gui.visible = false
+
+        extend {
+            // determine visibility through mouse x-coordinate
+            gui.visible = mouse.position.x < 200.0
+
+            drawer.fill = settings.color
+            drawer.circle(settings.position * drawer.bounds.position(1.0, 1.0), settings.radius)
+            drawer.circles(
+                    settings.radii.mapIndexed { i, radius ->
+                        Circle(width - 50.0, 60.0 + i * 70.0, radius)
+                    }
+            )
+        }
+    }
+}

orx-gui/src/main/kotlin/Gui.kt

@@ -72,12 +72,23 @@ class GUI : Extension {
     private var onChangeListener: ((name: String, value: Any?) -> Unit)? = null
     override var enabled = true
 
-    private var visible = true
+    var visible = true
+    set(value) {
+        if (field != value) {
+            field = value
+            if (field) {
+                panel?.body?.classes?.remove(collapsed)
+            } else {
+                panel?.body?.classes?.add(collapsed)
+            }
+            sidebarState().hidden = !field
+        }
+    }
 
     var compartmentsCollapsedByDefault = true
     var doubleBind = false
 
-    private lateinit var panel: ControlManager
+    private var panel: ControlManager? = null
 
     // Randomize button
     private var shiftDown = false
@@ -95,12 +106,8 @@ class GUI : Extension {
                 println("f11 pressed")
                 visible = !visible
 
-                if(visible) {
-                    panel.body!!.classes.remove(collapsed)
-                } else {
-                    panel.body!!.classes.add(collapsed)
-                }
-                sidebarState().hidden = !visible
+
+
             }
 
             if (it.key == KEY_LEFT_SHIFT) {
@@ -341,13 +348,9 @@ class GUI : Extension {
         }
 
         visible = !sidebarState().hidden
-        if(visible) {
-            panel.body!!.classes.remove(collapsed)
-        } else {
-            panel.body!!.classes.add(collapsed)
-        }
 
-        program.extend(panel)
+
+        program.extend(panel ?: error("no panel"))
     }
 
     /* 2) control creation. create control, set label, set range, setup event-handler, load values */