8.1.1 The purpose of VCL

The VRR Canvas Library (VCL) is an implementation of a canvas widget with support for all features needed in VRR . It provides this services:

• Widget-like manipulation with drawing primitives (lines, curves, ...)
• Automatic redrawing of invalid regions (after expose-events or some changes in the canvas)
• Interface for different drawing back-ends (supports GDK background and Cairo background)

The library is an almost independent part of the project and uses only VRRLIB definitions.