8.1.1 The purpose of VCL
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.