Basic line algorithms

1. Must compute integer coordinates of pixels which lie on or near a line or circle.
2. Pixel level algorithms are invoked hundreds or thousands of times when an image is created or modified.
3. Lines must create visually satisfactory gvu/multimedia/nsfmmedia/images.
   • Lines should appear straight
   • Lines should terminate accurately
   • Lines should have constant density
   • Line density should be independent of line length and angle.
4. Line algorithm should always be defined.