Hi, I have a Bitmap object called A and a Bitmap object called B. I want to produce a Bitmap object C that is produced by XORing the pixels values from A against the pixel values from B. Specifically, the integer pixel values should be combined using bitwise XOR.
The reason I want this is when transforming some bitmap from image A to B, I want to produce an image of the differences C so that I can convert B back to A by XORing C onto B. I've tried drawing bitmap A onto B using a Paint object with .setXferMode(PorterDuffXfermode(PorterDuff.Mode.XOR))) but this does not perform a bitwise XOR on the pixel values as the alpha values are treated as special cases as it says in the documentation (i.e. XORing C onto B does not generate A when non-opaque pixels are used): http://developer.android.com/reference/android/graphics/PorterDuff.Mode.html "PorterDuff.Mode XOR [Sa + Da - 2 * Sa * Da, Sc * (1 - Da) + (1 - Sa) * Dc] " I tried variations of .setXfermode(new PixelXorXfermode(0)) but the documentation says PixelXorXfermode does not consider the alpha values at all. Is there any efficient ways to do what I want here with API calls? If there really isn't a XOR paint mode I can use, perhaps there are some weird tricks I could use to do this. The only method I can see is to use .copyPixelsToBuffer to copy A and B into int arrays, XOR the arrays with a for loop, then copy the pixels into C. This uses a lot of memory and could be done faster if it was performed in-place by some native function. Or perhaps there are smarter ways to do this? Thanks. -- You received this message because you are subscribed to the Google Groups "Android Developers" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/android-developers?hl=en
