[orx-fx] Add Duotone, DuotoneGradient, LumaHalftone, Posterize, RgbToOkLab, OkLabToRgb

orx-fx/src/demo/kotlin/DemoDitherLumaHalftone01.kt

@@ -0,0 +1,26 @@
+import org.openrndr.application
+import org.openrndr.draw.createEquivalent
+import org.openrndr.draw.loadImage
+import org.openrndr.extra.fx.dither.LumaHalftone
+import org.openrndr.math.mod_
+
+fun main() {
+    application {
+        program {
+            val image = loadImage("demo-data/images/image-001.png")
+            val filteredImage = image.createEquivalent()
+            val lumaHalftone = LumaHalftone()
+            extend {
+                lumaHalftone.rotation = -15.0
+                lumaHalftone.freq0 = 100.0
+                lumaHalftone.gain1 = 1.0
+                lumaHalftone.threshold = 0.5
+                lumaHalftone.phase0 = seconds*0.1
+                lumaHalftone.phase1 = -seconds*0.1
+                lumaHalftone.apply(image, filteredImage)
+                lumaHalftone.invert = seconds.mod_(2.0) < 1.0
+                drawer.image(filteredImage)
+            }
+        }
+    }
+}