[vtk-developers] vtkCamera: add an equivalent to UseHorizontalViewAngle for parallel projection?

[Stefan Pfeifer]

Hi everyone,

So the vtkCamera interprets the view angle as vertical by default. This 
can be changed via

     camera->SetUseHorizontalViewAngle(true);

One of the effects is that the resizing behaviour of the windows 
changes: The view now gets adjusted when the window's width changes, not 
the height as before. At least that's my use case.

My problem is that this doesn't work with the parallel projection, as 
there is no equivalent method to change the direction of the 
ParallelScale. It's always vertical. So my suggestion would be to add 
exactly that. Maybe call it SetUseHorizontalParallelScale so it would be 
consistent with the Get/Set methods:

     Perspective: Get/SetViewAngle <-> Get/SetUseHorizontalViewAngle
     Parallel: Get/SetParallelScale <-> Get/SetUseHorizontalParallelScale

I haven't contributed before so I wanted to get some feedback on this 
first. It doesn't seem very difficult to implement, so if you guys think 
it makes sense I could give it a try.

Best regards
Stefan