An efficient way to draw images when you need to access individual pixels is
to use the bitmap ScanLine property. For general-purpose usage, you can set up
the bitmap pixel format to 24 bits and then treat the pointer returned from
ScanLine as an array of RGB. Otherwise, you will need to know the native format
of the ScanLine property. This example shows how to use ScanLine to get pixels
one line at a time.
自己处理BITMAP上的点
