The confusion (and I will try to update the dox to make this clearer) is that the color int is in unpremultipled form, but the internal format for Bitmap pixels is premultiplied.
"premultiplied" means that the r,g,b components have already been multiplied by their respective alpha value. Thus 50% transparent Red would be stored as 0x80800000 "unpremultipled" means that the r,g,b components are stored in their raw form, independent of the alpha value. Thus 50% transparent Red would be stored as 0x80FF0000 Thus when you specify 0x08040201 in unpremultiplied form (as you should for the input to setPixels), that color is internally converted to its premultiplied equivalent, which in this case happens to be 0x08000000. When you call getPixels(), the values are converted back to unpremultiplied form automatically, but in this case there is no change. mike On Sep 23, 2008, at 10:40 AM, JakeMaui wrote: I have a bitmap issue. I created a simple PNG that was 1 pixel high, 16 wide pure white. I loaded the bitmap, extracted the pixels, changed the first one and then created a bitmap from the altered data. The issue is that I thought that until I save it, I would have a raw bitmap will all the bits set as I had set them. I found that the bits changed. Does anybody know what I need to do to preserve the bitmap with the bits that I set into it? sample code ... int picw= bitmap.getWidth(); int pich=bitmap.getHeight(); int[] pix = new int[picw*pich]; bitmap.getPixels(pix, 0, picw, 0, 0, picw, pich); // It's pure white at this point. // I set the first byte to this but when I pull it out of the newly constructed // bitmap, it's 0x8000000 pix[0]=0x08040201; createdBitmap = Bitmap.createBitmap(picw, pich, Bitmap.Config.ARGB_8888); createdBitmap.setPixels(pix, 0, picw, 0, 0, picw, pich); // get pixels of newly created bitmap int picw= embeddedBitmap.getWidth(); int pich=embeddedBitmap.getHeight(); int[] pix = new int[picw*pich]; createdBitmap.getPixels(pix, 0, picw, 0, 0, picw, pich); Results .... 00001000 00000100 00000010 00000001 before 00001000 00000000 00000000 0000000 --~--~---------~--~----~------------~-------~--~----~ 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 -~----------~----~----~----~------~----~------~--~---
