Category methods should be prefixed

[PeteC]

Category methods should be prefixed so they don't clash with other libraries or with methods that may be added by Apple in the future. This is especially important for methods that are likely to be implemented elsewhere such as "fontName".

Also see:
https://developer.apple.com/library/ios/documentation/cocoa/conceptual/ProgrammingWithObjectiveC/CustomizingExistingClasses/CustomizingExistingClasses.html

[jamztang]

Yes I agreed. We should probably add a prefix as you suggested, or implement a "canvas" object property for all kinds of configurations. We'd need some thoughts on that and improve that on next version.