Actually figured it out in the end! :)
Bitmap bm = Bitmap.createBitmap(500, 500, Bitmap.Config.RGB_565); Canvas c = new Canvas(bm); Paint paint = new Paint(); ColorMatrix cm = new ColorMatrix(); cm.setSaturation(0); ColorMatrixColorFilter f = new ColorMatrixColorFilter (cm); paint.setColorFilter(f); int xo = (w-500)/2; int yo = (h-500)/2; c.drawBitmap(bmp, -xo, -yo, paint); bmp.recycle(); Cheers. On May 20, 12:07 pm, moa <mich...@jixel.com> wrote: > I would like to convert a Bitmap to a grayscale array of bytes (one > byte per pixel). At the same time I want to just crop at section from > the middle. Having looked though the various api's it is not clear to > me what the best way would be. > > The best way I have found in se java is as below; > > BufferedImage image = new BufferedImage(cropWidth, cropHeight, > BufferedImage.TYPE_BYTE_GRAY); > Graphics g = image.getGraphics(); > g.drawImage(colorImage, cropOffsetX, cropOffsetY, null); > g.dispose(); > > Leaving me with a graysale image of the right section; > > What is the equivalent method with android api's. I am guessing it is > along these lines.... > > Bitmap bm = Bitmap.createBitmap(500, 500, > Bitmap.Config.ALPHA_8); // ALPHA_8? > Canvas c = new Canvas(bm); > Paint paint = new Paint(); // should something be set > here to get grayscale? > c.drawBitmap(bm, 200, 200, paint); > bm..getPixels(...); // I want byte/pixel not int/ > pixel ?? > > However, I have two questions; > > 1) What is ALPHA_8? is that grayscale? > > I have a feeling that the grayscale effect should be done via some > "saturation" on the paint object, right? > > 2) once I have the Bitmap in grayscale and the right size, what is the > best way to get that to a byte[] of pixels (one byte per pixel) ? > > Thanks. --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Android Developers" group. To post to this group, send email to android-developers@googlegroups.com To unsubscribe from this group, send email to android-developers-unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/android-developers?hl=en -~----------~----~----~----~------~----~------~--~---