Device context

A device context is an abstraction away from devices such as windows, printers and files. Code that draws to a device context is generic since that device context could be associated with a number of different real device. A canvas has a device context, although duplicate graphics calls are provided for the canvas, so the beginner doesn't have to think in terms of device contexts when starting out. wxWindows supports device contexts for canvas, Windows printer, and Encapsulated PostScript files on UNIX.