2006.05.09 22:11 "Re: [Tiff] TIFF Rotation", by Bob Friesenhahn
Well, I've tried to dodge this, but I don't see another option. I need to be able to rotate TIF's by 90, 180, or 270 degrees. Near as I can tell, there's not really any support for this in libtiff, and I don't
There is not any support in libtiff for this functionality. It is very difficult to implement in libtiff. In order to implement it, the image must be decoded into a buffer, including provision for any extra samples. The amount of the image which needs to be decoded depends on the storage organization (packed, planar, tiled, strips) and the rotation requested. Libtiff does have crude support for decoding common TIFF types into an 8-bit deep RGBA image buffer, and discarding any extra samples. This crude support is only suitable for simple viewer applications since it does not support all permutations, and may discard a considerable amount of data (e.g. 16 bits crushed to 8 bits, discard extra samples).
What you are looking for can certainly be done but it is not easy, and is likely something that you will have to implement yourself and contribute to the project.
GraphicsMagick Maintainer, http://www.GraphicsMagick.org/