image comparison

Hello,

My Strategy with PIL is :

• Extract the image from the screen (1024*1024). As the image is displayed in an application, get the window coordonate of the application, and then get only the window of the application  (for instance (15,15) to (255,255))
• You know the structure of application, so you know where the actual image is, so extact it
• Now you have the expected and the actual pictures
• In fact in my case, I reduce the comparison size, because only a part tof the picture is useful
• The easiest way to compare the images, is to convert them to a raw list of pixels, then you have just ot do a octet comparaiso

The last step could be more complex in case of "String" comparaison. The antializing mechanism modify the color of some pixels to allow a better human reading, but the comparaison is more complex.

I hope this will help you