TIFF and JPEG files can contain an Orientation setting describing how the image
would be most naturally viewed.
The AppliedOrientation property specifies a transform which will
be applied to the image for presentation. The values here parallel
the Orientation values and are designed to undo the reflections and
rotations that each of those Orientation values represent.
As such the default value value for this property is the value
of Orientation which means that the
image will always be transformed to present as it was intended.
The negative sign of each transform represents an initial swap
of the x and the y coordinates while the absolute value represents
the angle of a final clockwise rotation. The rotation is clockwise
because, by default, scan lines go from top to bottom.
The following transforms are legal.
- 0 — identity.
- -90 — reflect across the vertical mid-line, i.e. flips x.
- 180 — rotate 180°.
- -270 — reflect across the horizontal mid-line, i.e. flips
- -360 — reflect across the major diagonal, i.e. swaps x and
- 90 — rotate 90° clockwise.
- -180 — reflect across the minor diagonal.
- 270 — rotate 270° clockwise.
When this property is changed, both Selection and BoundingBox are re-oriented. If the
orientation and transform combine to produce a 90 or 270 degree
rotation, axis-specific values like Width /
Height and HRes /
VRes will be swapped.
Changing the value of this property may result in an exception
being thrown if the file format or XReadOptions.ReadModule
does not support orientation (e.g. SWF, PostScript, etc.).