Hi, I'm writing an image editing application, making use of the Bitmap and Canvas classes, and I need to edit the colors of pixels in specific ways for some operations. For example, I'd like to be able to XOR pixel values and create a multiply filter that works the same way as in desktop image software.
With the current Porter Duff modes available (http:// developer.android.com/reference/android/graphics/PorterDuff.Mode.html) that you set with Paint.setXfermode(..) I can't do either of these as the XOR mode and multiply mode available don't treat alpha values the way that I want. For example, the XOR operation should just XOR all the bits together and not perform any calculations based on the alpha value (Canvas does the latter when XOR is set). My solution at the moment is to dump the two bitmaps I'm working with to int arrays, perform the operation by hand using the int arrays (NDK use would speed this up) and the copy the int arrays back. This is slow and cumbersome and also means I can't e.g. use operations like Canvas.drawBitmap with the filters I want. Is it possible to introduce my own Porter Duff modes (e.g. using the NDK)? This would be a much more elegant solution for me. I'd appreciate any advice on alternative solutions too. As far as I'm aware, it isn't possible to modify the contents of Bitmap objects directly without copying to int arrays first. 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
