Defined as
Public Enum PlotRotation
' Fields
Degrees000 = 0
Degrees090 = 1
Degrees180 = 2
Degrees270 = 3
End Enum
And looks like should be
Degrees000 = Portrait
Degrees090 = Landscape
Degrees180 = Portrait - Upside doown checked
Degrees270 = Landscape - Upside doown checked
Shouldn't "Portrait/Landscape" be decide by both Rotation and paper's Heigh/Width?
That is, for a paper with its height greater than its width, Degree000 mean Portrait, while for a paper with its heigh is less than its width, Degree000 means Landscape. So, if you want to make sure the plot is portrait or landscale, you need to know the defined paper size, than rotate it accordingly.