Add screenshot generation

orx-gui/build.gradle

@@ -15,6 +15,7 @@ dependencies {
     implementation "com.google.code.gson:gson:$gsonVersion"
     implementation "org.jetbrains.kotlin:kotlin-reflect:$kotlinVersion"
     demoImplementation("org.openrndr:openrndr-core:$openrndrVersion")
+    demoImplementation("org.openrndr:openrndr-extensions:$openrndrVersion")
     demoRuntimeOnly("org.openrndr:openrndr-gl3:$openrndrVersion")
     demoRuntimeOnly("org.openrndr:openrndr-gl3-natives-$openrndrOS:$openrndrVersion")
     demoImplementation(sourceSets.getByName("main").output)

orx-gui/src/demo/kotlin/DemoOptions01.kt

@@ -1,5 +1,6 @@
 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
@@ -23,6 +24,11 @@ fun main() = application {
         }
 
         gui.add(settings)
+        if (System.getProperty("takeScreenshot") == "true") {
+            extend(SingleScreenshot()) {
+                this.outputFile = System.getProperty("screenshotPath")
+            }
+        }
         extend(gui)
         extend {
             when(settings.option) {

orx-gui/src/demo/kotlin/DemoSimple01.kt

@@ -1,5 +1,6 @@
 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
@@ -22,10 +23,13 @@ fun main() = application {
 
             @DoubleListParameter("a double list")
             var adl = MutableList(2) { 0.0 }
-
         }
-
         gui.add(settings)
+        if (System.getProperty("takeScreenshot") == "true") {
+            extend(SingleScreenshot()) {
+                this.outputFile = System.getProperty("screenshotPath")
+            }
+        }
         extend(gui)
         extend {
             drawer.fill = settings.color