Thread: Messing with alpha

I am using something a kin to this:

        for (int w=0;w<bi.getWidth();w++) {          
        for (int h=0;h<bi.getHeight();h++) {
            int color = bi.getRGB(w, h);
            color = color << 5;
   	    bi.setRGB(w, h, color);
 
        }
 
    }

I am using a solid green image so

 11111111000000001111111100000000

I just wanted to see how it looked so bumped it over 5 places (obviously changing the color). To my surprise, there was no added transparency. I mean moving it to the left would make the alpha:

11100000

I am thinking that setRGB() doesn't effect alpha. Is this accurate?


*UPDATE*

Tested it and in fact setRGB has no effect on the alpha bits. So now the question is how can I gain access to them. Any help is appreciated; personally I am going to look into the writable Raster API. Perhaps, I can also use a modified awt to access directly OS data.

I recommend posting an SSCCE that reproduces the problem - the code posted is not clear as to what 'bi' is (BufferedImage?) and how it was constrcted (if a BufferedImage - does it have alpha, how are the bits arranged (rgba, argb, rgb, etc...).?)