From 95b184cab9b3b4b81c1425a40d06c2de95075ef6 Mon Sep 17 00:00:00 2001
From: Tomas Mikula <tomas.mikula@gmail.com>
Date: Sun, 15 Feb 2015 03:02:27 -0500
Subject: [PATCH] Add convenient animation for Interpolatable types.

---
 .../org/reactfx/demo/AnimatedValDemo.java     | 14 +++++++++--
 .../java/org/reactfx/util/Interpolator.java   |  5 ++++
 .../src/main/java/org/reactfx/value/Val.java  | 23 +++++++++++++++++++
 3 files changed, 40 insertions(+), 2 deletions(-)

diff --git a/reactfx-demos/src/main/java/org/reactfx/demo/AnimatedValDemo.java b/reactfx-demos/src/main/java/org/reactfx/demo/AnimatedValDemo.java
index 11c175a..a196425 100644
--- a/reactfx-demos/src/main/java/org/reactfx/demo/AnimatedValDemo.java
+++ b/reactfx-demos/src/main/java/org/reactfx/demo/AnimatedValDemo.java
@@ -20,9 +20,10 @@ public class AnimatedValDemo extends Application {
 
     @Override
     public void start(Stage primaryStage) {
-        Circle circle = new Circle(30.0, Color.BLUE);
+        Circle circle = new Circle(30.0);
         Pane canvas = new Pane(circle);
 
+        // animate circle position
         Var<Point2D> center = Var.newSimpleVar(new Point2D(W/2, H/2));
         Val<Point2D> animCenter = center.animate(
                 (p1, p2) -> Duration.ofMillis((long) p1.distance(p2)),
@@ -31,12 +32,21 @@ public void start(Stage primaryStage) {
         circle.centerXProperty().bind(animCenter.map(Point2D::getX));
         circle.centerYProperty().bind(animCenter.map(Point2D::getY));
 
-        Random random = new Random();
+        // animate circle color
+        Var<Color> color = Var.newSimpleVar(Color.BLUE);
+        Val<Color> animColor = Val.animate(color, Duration.ofMillis(500));
+        circle.fillProperty().bind(animColor);
 
+        // on click, move to random position and transition to random color
+        Random random = new Random();
         circle.setOnMouseClicked(click -> {
             center.setValue(new Point2D(
                     random.nextInt(W),
                     random.nextInt(H)));
+            color.setValue(Color.rgb(
+                    random.nextInt(240),
+                    random.nextInt(240),
+                    random.nextInt(240)));
         });
 
         primaryStage.setScene(new Scene(canvas, W, H));
diff --git a/reactfx/src/main/java/org/reactfx/util/Interpolator.java b/reactfx/src/main/java/org/reactfx/util/Interpolator.java
index 68527f3..ab5badf 100644
--- a/reactfx/src/main/java/org/reactfx/util/Interpolator.java
+++ b/reactfx/src/main/java/org/reactfx/util/Interpolator.java
@@ -1,6 +1,7 @@
 package org.reactfx.util;
 
 import static javafx.animation.Interpolator.*;
+import javafx.animation.Interpolatable;
 
 /**
  * Interpolates values between two boundary values.
@@ -52,4 +53,8 @@ public interface Interpolator<T> {
 
     static final Interpolator<Long> EASE_OUT_LONG =
             (a, b, frac) -> EASE_OUT.interpolate(a.longValue(), b.longValue(), frac);
+
+    static <T extends Interpolatable<T>> Interpolator<T> get() {
+        return (a, b, frac) -> a.interpolate(b, frac);
+    }
 }
diff --git a/reactfx/src/main/java/org/reactfx/value/Val.java b/reactfx/src/main/java/org/reactfx/value/Val.java
index 2de7f12..a7bafb2 100644
--- a/reactfx/src/main/java/org/reactfx/value/Val.java
+++ b/reactfx/src/main/java/org/reactfx/value/Val.java
@@ -10,6 +10,7 @@
 import java.util.function.Predicate;
 import java.util.function.Supplier;
 
+import javafx.animation.Interpolatable;
 import javafx.beans.InvalidationListener;
 import javafx.beans.Observable;
 import javafx.beans.property.Property;
@@ -464,6 +465,28 @@ static <T> Val<T> animate(
         return animate(obs, (a, b) -> duration, interpolator);
     }
 
+    /**
+     * Like {@link #animate(ObservableValue, BiFunction, Interpolator)}, but
+     * uses the interpolation defined by the {@linkplain Interpolatable} type
+     * {@code T}.
+     */
+    static <T extends Interpolatable<T>> Val<T> animate(
+            ObservableValue<T> obs,
+            BiFunction<? super T, ? super T, Duration> duration) {
+        return animate(obs, duration, Interpolator.get());
+    }
+
+    /**
+     * Like {@link #animate(ObservableValue, Duration, Interpolator)}, but
+     * uses the interpolation defined by the {@linkplain Interpolatable} type
+     * {@code T}.
+     */
+    static <T extends Interpolatable<T>> Val<T> animate(
+            ObservableValue<T> obs,
+            Duration duration) {
+        return animate(obs, duration, Interpolator.get());
+    }
+
 
     static <A, B, R> Val<R> combine(
             ObservableValue<A> src1,