tk是一个结合tcl语言开发图形图像的脚本，如风河的Tornado就是用tcl＋tk开发的IDE。-tk is a combination of language development tcl scr ipt graphic images, such as wind River Tornado is to use tcl tk development IDE.

图形学的Bresenham算法的实现 有程序和说明 不错的(The realization of the graphics Bresenham algorithm has good application and specification)