[SDL] per-pixel alpha stuff

Mattias Engdegård f91-men at nada.kth.se
Tue Jan 9 11:49:58 PST 2001

>I'm playing around with various algorithms for antialiasing lines (don't ask
>me why), and it occured to me to try and make something that functions with
>per-pixel alpha blending instead of linear, foreground-to-background color
>blending. Now I wonder, is this possible using SDL?

SDL can alpha-blend a surface onto another, so you could render an antialiased
line on an RGBA surface and blit it. But that is probably wasteful since
you would have to make the surface the bounding box of your line; better
combine each pixel of your line the way you want it

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