Fix the svg:use. For a svg:use, it is a group which include the content it reference. It means that we can not tween it to its origin object directly. Instead, we need to ungroup it and then use the result matrix to generate the tweened transformation matrix. Therefore, we need to concate its matrix to the referenced object. Ad center object when the bbox-x is not available.

Scene 1: Main category

1. Start to load all pictures and save them in the file system.
2. Load the main screen and move all pictures to the correct positions.
3. Show the cursor and do animation to scale it.
4. After the animation, start to listent to keys and move the cursor.
5. If the key is enter, load the next scene.


Scene 2: