2002.08.15 00:52 "Re: Orientation field", by Jon Saxton
** Reply to message from Dante Allegria <firstname.lastname@example.org> on Wed, 14 Aug 2002 20:33:41 -0400 (EDT)
Does anyone know if anybody supports the Orientation field? It would be nice for apps that output bottom-up instrinsically to not have to do any exra work.
Some do, some don't. According to the specification document, readers aren't required to support it.
Mind you, not supporting the orientation tag is pure laziness. For the writer of a viewer using any of the windowed interfaces of modern operating systems, displaying the image correctly is usually just a matter of setting up the destination rectangle coordinates correctly and that only takes a very few lines of code.
Many times I have had to write code to flip or rotate images because viewers assume that orientation is always 1, i.e. 4th quadrant. On the other hand, sometimes I have been able to logically flip or rotate images of documents that were fed through a scanner incorrectly by just tweaking the orientation tag. Everything depends on the capabilities of the end user software.
Jon Saxton <email@example.com>
Developer of cross-platform software for UNIX, OS/2 and Win32
U.S. agent for Triton Technologies International Ltd