box2d and parallax

lib/box2d/box2d_component.dart

@@ -111,17 +111,17 @@ class Viewport extends ViewportTransform {
       : super(new Vector2(dimensions.width / 2, dimensions.height / 2),
       new Vector2(dimensions.width / 2, dimensions.height / 2), scale);
 
-  double alignBottom(double height) =>
+  double worldAlignBottom(double height) =>
       -(dimensions.height / 2 / scale) + height;
 
   /**
-   * Computes the number of horizontal pixels of this viewport considering a
+   * Computes the number of horizontal world meters of this viewport considering a
    * percentage of its width.
    *
    * @param percent percetage of the width in [0, 1] range
    */
-  double width(double percent) {
+  double worldWidth(double percent) {
-    return percent * (dimensions.width / 2 / scale);
+    return percent * (dimensions.width / scale);
   }
 }
 
@@ -202,7 +202,8 @@ abstract class BodyComponent extends Component {
   }
 
   void drawPolygon(Canvas canvas, List<Offset> points) {
-    final path = new Path()..addPolygon(points, true);
+    final path = new Path()
+      ..addPolygon(points, true);
     final Paint paint = new Paint()
       ..color = new Color.fromARGB(255, 255, 255, 255);
 //      ..style = PaintingStyle.stroke;

lib/component.dart

@@ -100,8 +100,10 @@ class ParallaxComponent extends PositionComponent {
       return;
     }
 
+    canvas.save();
     prepareCanvas(canvas);
     _drawLayers(canvas);
+    canvas.restore();
   }
 
   void _drawLayers(Canvas canvas) {