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[REBOL] Re: Masking, Keying and Image Composition ideas.

From: antonr:iinet:au at: 24-May-2003 21:03

I noticed a bug when making pixel-boy.r where the alpha channel wouldn't appear until the top-left pixel of the image had its alpha channel value set. You set the top-left pixel, and magically the alpha channel appears. I've already sent a bug report for that. Maybe that will help you. Here's code which demonstrates the bug: img: make image! 2x1 poke img 1 poke img 2 ?? img img2: make image! 2x1 poke img2 1 poke img2 2 ?? img2 view center-face layout [ image 64 * img/size img ; as expected image 64 * img2/size img2 ; where's the alpha ? ] I don't understand what the problem is with 'repeat in your comment at the bottom. I am sure if you replace: for v 1 (img/size/x * img/size/y) 1 [...] with: repeat v (img/size/x * img/size/y) [...] that it will work identically, faster, and you won't have to declare 'v as local to the function, either. Also, for a bit extra speed, use: equal? c pick mask v rather than: (pick mask v) = c The parens and the '= cause the interpreter to do more work. not-equal? c pick mask v is also faster than: not (pick mask v) = c Anton Rolls.