Turning imageData into alphaData (quickly)?

[sims]

>Hi all, I've been lurking for a few years, but not posted for some time...
>
>I'm doing quite a lot of stuff generating PNGs with transparency, 
>and wondered if there is any fast way to combine an 'image' img and 
>a 'transparency' img?
>A handler that goes through each RGB pixel and reduce it to a 
>grayscale value for use as alphaData was pretty easy, but for a 
>200x200px image that's 40,000 repeats, and takes minutes on a G5.

Perhaps the following might help?
Also, I think Chipp has done some work along those lines.

I have uploaded a series of images created with the "ImageData Toolkit",
which is a modified version of my "Colorpattern Toolkit"
(<http://www.sanke.org/ImageDataArt>).


ciao,
sims

European Rev Conference  2006
www.techietours.com