Remove the alpha from a colour but retain its texture

Question

I have a colour #6A8F6509

I wish to remove the Alpha part of that colour and be left with only RGB components (i.e. #RRGGBB).

The resulting colour must look identical to the initial one without the transparency.

How do I go about this on Android's Java?

Update: The initial background is always white (#FFF)

Answer 1

int newColor = oldColor | 0xFF000000;

Answer 2

If you want to do it with the code you can try following code:

    static int stripAlpha(int color){
    return Color.rgb(Color.red(color), Color.green(color), Color.blue(color));
}

Answer 3

For each color: C' = C(a/255) + 255(1-(a/255))

So for #6A8F6509:

R' = 143(106/255) + 255(1-(106/255) = (approx) 208

G' = 101(106/255) + 255(1-(106/255) = (approx) 191

B' = 9(106/255) + 255(1-(106/255) = (approx) 153

So your answer should be: #D0BF99, if my math is correct. This only applies to an all white background as well - for a non-white background, the second addend should have the appropriate corresponding color value of the background instead of 255.

-- EDIT --

Looking at the formula again, I'm not entirely sure whether the formula gets applied to each color or the entire color (a quick visual test should be able to tell you - I'm guessing per color). I should point out that this is the formula direct from the Alpha Compositing wiki page:

http://en.wikipedia.org/wiki/Alpha_compositing#Alpha_blending

Answer 4

try

#FF8F6509

the first two digits indicate the alpha value of any color.