Fixes and move to jvmDemo (#286)

orx-shade-styles/src/jvmDemo/kotlin/DemoNPointLinearGradient01.kt

@@ -0,0 +1,66 @@
+import org.openrndr.application
+import org.openrndr.color.ColorXSVa
+import org.openrndr.color.rgb
+import org.openrndr.extra.color.spaces.toOKLABa
+import org.openrndr.extra.shadestyles.NPointLinearGradient
+import org.openrndr.extra.shadestyles.NPointLinearGradientOKLab
+import org.openrndr.shape.Rectangle
+import kotlin.math.pow
+import kotlin.math.sin
+
+/**
+ * Demonstrate using a multicolor linear gradient.
+ * The gradient has 8 static saturated colors.
+ * The positions of the colors are first distributed
+ * uniformly between 0.0 and 1.0 and then animated towards one of
+ * the ends over time using pow() and sin(seconds).
+ */
+fun main() {
+    application {
+        program {
+            val numPoints = 8
+            // Create gradients using two different color spaces
+            val gradients = listOf(
+                NPointLinearGradient(Array(numPoints) {
+                    ColorXSVa(it * 360.0 / numPoints, 1.0, 1.0).toRGBa()
+                }),
+                // OKLab is better at maintaining luminosity across the gradient
+                NPointLinearGradientOKLab(Array(numPoints) {
+                    ColorXSVa(it * 360.0 / numPoints, 1.0, 1.0).toRGBa()
+                        .toOKLABa()
+                })
+            )
+
+            extend {
+                // The points should be sorted values between 0.0 and 1.0
+                val distribution = Array(numPoints) {
+                    // uniform distribution
+                    // (it / (numPoints - 1.0))
+
+                    // skewed and animated distribution
+                    (it / (numPoints - 1.0)).pow(1.0 + 0.5 * sin(seconds))
+                }
+                drawer.run {
+                    clear(rgb(0.2))
+                    stroke = rgb(0.35)
+                    strokeWeight = 8.0
+
+                    gradients.forEachIndexed { i, gradient ->
+                        shadeStyle = gradient
+                        gradient.points = distribution
+
+                        gradient.rotation = seconds * 10
+                        circle(bounds.position(0.34, 0.29 + 0.44 * i), 110.0)
+
+                        gradient.rotation += 90
+                        rectangle(
+                            Rectangle.fromCenter(
+                                bounds.position(0.655, 0.29 + 0.44 * i), 200.0
+                            )
+                        )
+                    }
+                }
+            }
+        }
+    }
+}