Vincent Povirk <madewokh...@gmail.com> wrote: > You should at least look at the stream and check that it looks like an > image in a format the decoder can read.
An invalid image format is a completely not related case, that I'd prefer ignore for now. > For PNG, you could maybe argue that given a correct magic number and a > correctly-working decoder, the decoder must be able to read all the > images or either the decoder or image is broken. Then again, you're > not even checking the magic number.. > > For TGA, though, we don't have an exact magic number. It's entirely > possible that we our TGA magic number matches some files that aren't > really TGA images but are images in some other format that we can > decode. We need QueryCapabilities to disambiguate the decoders in > these cases. > > For JPEG and TIFF, which are extensible formats, there's also the > possibility that an image has something in it that we don't support > (and that the corresponding decoder on Windows doesn't support) but > some other decoder on the system can. A not supported stream format is a bug and should be fixed IMO. I believe that an implementation which declares support for all formats is better than a not implemented stub. -- Dmitry.
