Fixing example and restoring SpriteComponent

lib/components/component.dart

@@ -171,3 +171,36 @@ abstract class PositionComponent extends Component {
     _effects.removeWhere((e) => e.hasFinished());
   }
 }
+
+/// A [PositionComponent] that renders a single [Sprite] at the designated position, scaled to have the designated size and rotated to the designated angle.
+///
+/// This is the most commonly used child of [Component].
+class SpriteComponent extends PositionComponent {
+  Sprite sprite;
+  Paint overridePaint;
+
+  SpriteComponent();
+
+  SpriteComponent.square(double size, String imagePath)
+      : this.rectangle(size, size, imagePath);
+
+  SpriteComponent.rectangle(double width, double height, String imagePath)
+      : this.fromSprite(width, height, Sprite(imagePath));
+
+  SpriteComponent.fromSprite(double width, double height, this.sprite) {
+    this.width = width;
+    this.height = height;
+  }
+
+  @override
+  void render(Canvas canvas) {
+    prepareCanvas(canvas);
+    sprite.render(canvas,
+        width: width, height: height, overridePaint: overridePaint);
+  }
+
+  @override
+  bool loaded() {
+    return sprite != null && sprite.loaded() && x != null && y != null;
+  }
+}