It wasn't possible to temporarily orbit the view, then set back to an
axis-aligned view.
Details:
- It was possible to change RegionView3D.view_rotation while the view
kept the axis alignment value (Top, Left, Front .. etc) which
displayed in the viewport overlay.
Now changing the view rotation directly or via "view_matrix" resets
the axis-alignment - clearing when the view is no longer axis-aligned
or assigning the newly aligned axis.
- RegionView3D.is_orthographic_side_view added in [0] could be assigned
but wasn't useful as it treated an enum as a boolean only setting the
RegionView3D.view to RV3D_VIEW_USER or RV3D_VIEW_FRONT.
Now enabling this aligns the viewport rotation to it's closest
axis-aligned orientation setting RegionView3D.view & view_axis_roll
accordingly. Note that the "orthographic" term is misleading as the
property only relates to axis-alignment, not to the
perspective/orthographic setting. We could consider deprecating the
current naming.
[0]: 63bae864f4
3ecc03c3d6