TIFF Tag Orientation

TIFF Tag Orientation

IFD		Image
Code		274 (hex 0x0112)
Name		Orientation
LibTiff name		TIFFTAG_ORIENTATION
Type		SHORT
Count		1
Default		1

Description

The orientation of the image with respect to the rows and columns.

The specification defines these values:

1 = The 0th row represents the visual top of the image, and the 0th column represents the visual left-hand side.
2 = The 0th row represents the visual top of the image, and the 0th column represents the visual right-hand side.
3 = The 0th row represents the visual bottom of the image, and the 0th column represents the visual right-hand side.
4 = The 0th row represents the visual bottom of the image, and the 0th column represents the visual left-hand side.
5 = The 0th row represents the visual left-hand side of the image, and the 0th column represents the visual top.
6 = The 0th row represents the visual right-hand side of the image, and the 0th column represents the visual top.
7 = The 0th row represents the visual right-hand side of the image, and the 0th column represents the visual bottom.
8 = The 0th row represents the visual left-hand side of the image, and the 0th column represents the visual bottom.

The specification considers this a baseline tag, but does add that support for orientations other than 1 is not a Baseline TIFF requirement.

LibTiff defines these values:

ORIENTATION_TOPLEFT = 1;
ORIENTATION_TOPRIGHT = 2;
ORIENTATION_BOTRIGHT = 3;
ORIENTATION_BOTLEFT = 4;
ORIENTATION_LEFTTOP = 5;
ORIENTATION_RIGHTTOP = 6;
ORIENTATION_RIGHTBOT = 7;
ORIENTATION_LEFTBOT = 8;

Many readers ignore this tag.