These are all the possible values for the IG_ISIS_TAG_ORIENTATION, IG_ISIS_TAG_SCANORIENTATION and IG_ISIS_TAG_DATAORIENTATION tags.
Values:
IG_ISIS_ORIENTATION_PORT |
Portrait (0°). |
IG_ISIS_ORIENTATION_LAND |
Landscape (90° ccw). |
IG_ISIS_ORIENTATION_180 |
Upside down portrait (180° ccw). |
IG_ISIS_ORIENTATION_270 |
Upside down landscape (270° ccw). |
IG_ISIS_ORIENTATION_PORTM |
Portrait mirrored. |
IG_ISIS_ORIENTATION_LANDM |
Landscape mirrored. |
IG_ISIS_ORIENTATION_180M |
Upside down portrait mirrored. |
IG_ISIS_ORIENTATION_270M |
Upside down landscape mirrored. |