Thanks to everyone for the responses. A few comments:
Jay Cox wrote:
David Hodson wrote:
the opinion of (for example) Jim Blinn, and Thomas Porter and Tom Duff.
All three of whom come from a 3d rendered graphics background.
As do I.
For compositing and image warping pre multiplied
Nick Lamb wrote:
On Sun, Jul 16, 2000 at 05:37:56PM +1000, David Hodson wrote:
OK, this has been bugging me for some time. I'm convinced that Gimp's
alpha handling is wrong, in more than a few places.
OK, but please provide some concrete examples...
To start with, there should be a
On Wed, Jul 19, 2000 at 12:53:31AM +1000, David Hodson [EMAIL PROTECTED] wrote:
A hack? I thought it was a mathematically elegant representation of
an image layer, which is why I see a reason to support it. I'm trying
AFAICS premultiplied alpha is a speed hakc and nothing more, for cases where
It depends on what you are doing weather pre multiplied alpha is useful
or not. For compositing and image warping pre multiplied alpha is great. for
color correction pre-multiplied alpha just gets in the way. Since
pre-multiplying the alpha does throw away a few bits of information my
On Wed, Jul 19, 2000 at 12:53:31AM +1000, David Hodson wrote:
Can you justify that (all images should be pre-multiplied)?
Or is this just your unsupported opinion?
Well, that was attempted editorial humour to some extent, but it's also
the opinion of (for example) Jim Blinn, and Thomas
David Hodson wrote:
"Steinar H. Gunderson" wrote:
GIMP already does this (32-bit = RGBA, the `extra' 8 bits is an alpha channel,
used for transparency information), and has done for a long time now.
Calvin Williamson recommended "Image Composition
Fundamentals" by Alvy Ray Smith, for a
On Tue, Jul 18, 2000 at 09:41:49PM -0400, Garry R. Osgood wrote:
David Hodson wrote:
Example: render an rgba image. (I was using some PovRay output; I
presume it does a reasonable job.) Now create a flat colour
background in the Gimp, lay the rgba image on top, and try to get
a clean
"Steinar H. Gunderson" wrote:
GIMP already does this (32-bit = RGBA, the `extra' 8 bits is an alpha channel,
used for transparency information), and has done for a long time now.
OK, this has been bugging me for some time. I'm convinced that Gimp's
alpha handling is wrong, in more than a few
