The fun with PNG never seems to end.  And by "fun", I mean a hot poker in the 
eye.


On Jul 24, 2014, at 1:20 PM, Mikael Sundell <[email protected]> wrote:

> I seems as if Nuke writes data with associated alpha in PNG files, according 
> to the spec it's not valid:
> 
> http://www.libpng.org/pub/png/spec/1.2/PNG-DataRep.html
> 
> "The color values stored for a pixel are not affected by the alpha value 
> assigned to the pixel. This rule is sometimes called "unassociated" or 
> "non-premultiplied" alpha. (Another common technique is to store sample 
> values premultiplied by the alpha fraction; in effect, such an image is 
> already composited against a black background. PNG does not use premultiplied 
> alpha.)"
> 
> This causes the PNGReader to associateAlpha(…) on already alpha multiplied 
> data. Did anyone else experience this problem?
> 
> Mikael

--
Larry Gritz
[email protected]



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