2002.12.04 01:10 "libtiff gets the Orientation wrong", by Glenn Herteg
libtiff improperly handles the Orientation tag, pretending (in tif_getimage.c of tiff-v3.5.7) that only ORIENTATION_BOTLEFT and ORIENTATION_TOPLEFT make sense. The damage is done directly in the setorientation() routine, but there are probably correspondingly limited assumptions made in the rest of the code.
For code which (in tif_open.c) complains bitterly about bad implementations:
The following flags may be used to control
intrinsic library behaviour that may or
may not be desirable (usually for
compatibility with some application that
claims to support TIFF but only supports
some braindead idea of what the vendor
thinks TIFF is):
it is shameful that libtiff does not correctly support the full suite of Orientation values. A direct result is that viewers which depend on libtiff to parse TIFF files end up showing some images in an improperly flipped and/or rotated pose.