Manually fills a region of a picture. Since every pixel is modified directly by the code, you could do effects other than just filling, like gradient fill or bitmap fill.
来源: http://www.freevbcode.com/ShowCode.Asp?ID=719
用手填充一幅图片的区域。因为每一个像素都直接通过代码来修改,除了填充外你还可以通过其他方面达到效果,例如渐变填充或者位图填充。