2005.03.15 17:56 "[Tiff] Need to write CCITT T.6 encoded TIFF file data directly to memory buffer", by Roger Watkins

2005.03.16 19:38 "Re: [Tiff] Need to write CCITT T.6 encoded TIFF file data directlytomemory buffer", by Joris Van Damme


I am now more puzzled than ever.

I'm not sure what's so confusing. Why do you expect any reference to any particular codec in IO functions? Perhaps I should try and explain where exactly this IO comes into play...

The basic TIFF open function is TIFFClientOpen. This is not just the most basic of TIFF open functions, it is in fact the *only* TIFF open function on the platform independent LibTiff level. Amongst its parameters are pointers to IO functions. By providing pointers to file IO functions, you obtain TIFF reading/writing from/to file. By providing pointers to TStream IO functions you obtain TIFF reading/writing from/to TStream. The most widely used TIFFOpen is in fact a wrapper around TIFFClientOpen that passes pointers to file IO functions.

Let's look at this from another perspective. There's something like three layers involved here

More information about the various TIFFOpen flavours is here:


Does this all explain it?

Joris Van Damme
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