These constants define behavior of the cameras.
v3d.ViewportFitNone
v3d.ViewportFitVertical
v3d.ViewportFitHorizontal
v3d.ViewportFitAuto
v3d.ViewportFitFill
v3d.ViewportFitOverscan
These constants specify how viewport aspect ratio should affect horizontal, vertical, or both camera fields-of-view.
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