[osg-users] imageio problems and possible solutions on loading some PNG images.

Stephan Maximilian Huber ratzfatz at digitalmind.de
Thu Nov 26 08:09:43 PST 2009


Hi,

Tatsuhiro Nishioka schrieb:
> Another problem is that imageio's libpng doesn't properly handle transparency in PNG file. The problem I have is that the transparency in PNG files are not at all handled and we see a lot of unexpected black or dark portions.  I strongly recommend the use of osgdb_png.so (or .dylib) for handling png images instead of imageio.

looks like that the current implementation of imageio works with
premultiplied alpha, ideally all occurences of
kCGImageAlphaPremultipliedFirst should be replaced by
kCGImageAlphaFirst, but some test-data could help isolating the problem.

cheers,
Stephan



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