Let us use a Sprite + Path as an animation

git-svn-id: svn+ssh://src.earth.threerings.net/nenya/trunk@878 ed5b42cb-e716-0410-a449-f6a68f950b19

src/java/com/threerings/media/animation/SpritePathAnimation.java

@@ -0,0 +1,51 @@
+package com.threerings.media.animation;
+
+import java.awt.Graphics2D;
+import java.awt.Rectangle;
+
+import com.threerings.media.sprite.PathObserver;
+import com.threerings.media.sprite.Sprite;
+import com.threerings.media.util.Path;
+
+/**
+ * Wraps the dirty work of moving a sprite along a {@link Path} in an Animation.
+ */
+public class SpritePathAnimation extends Animation
+    implements PathObserver
+{
+    public SpritePathAnimation (Sprite sprite, Path path)
+    {
+        super(new Rectangle(0, 0, 0, 0)); // We don't render ourselves
+        _sprite = sprite;
+        _path = path;
+    }
+
+    @Override
+    public void paint (Graphics2D gfx) { }
+
+    @Override
+    public void tick (long tickStamp) { }
+
+    public void pathCancelled (Sprite sprite, Path path)
+    {
+        _finished = true;
+        sprite.removeSpriteObserver(this);
+    }
+
+    public void pathCompleted (Sprite sprite, Path path, long when)
+    {
+        _finished = true;
+        sprite.removeSpriteObserver(this);
+    }
+
+    @Override
+    protected void willStart (long tickStamp)
+    {
+        super.willStart(tickStamp);
+        _sprite.addSpriteObserver(this);
+        _sprite.move(_path);
+    }
+
+    final protected Sprite _sprite;
+    final protected Path _path;
+}