Most of the time, you just match the WorldAnnotator with the canvas of
the same type. Rather than make the user specify it every time, add a
method to the canvas that creates a "good" WorldAnnotator to use with
it. Then, if a WorldAnnotator is not given to the View constructor, one
is automatically created from the Canvas.
The template parameters on vtkm::rendering::View are unnecessary. All
three of the templated classes are polymorphic (with virtual functions).
Thus, you just have to specify them at the constructor. Removing the
template parameters makes the syntax a bit cleaner and removes some
unnecessary duplication in the executable.
Removing the template does mean we cannot optimize in the future.
However, I expect us to start using more virtual methods rather than
less, so I think this is a move in the right direction.
With only a few exceptions for simple structures, we do not expose the
members of classes. Instead, we provide accessor methods. Do this for
Camera as well as add some helper methods.
The width and height are maintained out of necessity by the canvas. A
second copy was maintained by the camera, which was only used for
computing the aspect ratio and similar metrics for projections.
Having to maintain the width/height in two places is a bit of a hassle
and provides the opportunity for bugs if they get out of sync. Instead,
have the width/height managed in one place (the canvas) and pass them as
parameters as necessary.
Generally we try not to expose the implementation details of how things
are stored in objects.
Also changed some arguments that should have been declared const to
actually be const.
The word surface is more often used for something like a polygonal mesh,
so this name is quite confusing. Canvas is consistent with a
conventional name in GUI widget APIs.
The rendering classes do not actually manage windows, and window was not
descriptive of what this class was doing. We decided that the class was
mostly analogous to what we call a "view" in ParaView.
