sb.getCanvas(name)
Get a canvas object handle by name. The canvas object has the following properties that can be accessed:
width: Returns an integer that is the width of the canvas. This is a read only property.
height: Returns an integer that is the height of the canvas. This is a read only property.
globalAlpha: This property can be used to get or set the global alpha for drawing operations in the canvas
lineWdith: This property can be used to get or set the linewidth for line drawing operations in the canvas
Parameters:
name The name of the canvas to get
Returns:
A canvas object that represents the canvas or null if no canvas can be found