[vtk-developers] policy on VTK API changes

[Ken Martin]

Hi Mike,

> Could Kitware establish and promote a consistent policy on API 
> changes?

Between patch releases maintain the API unless there is a really strong
reason not to. 

Between regular releases maintain backwards compatibility to the API with
prior releases of VTK when doing so does not increase the complexity or
readability of the current VTK or when the benefits of breaking the API are
negligible.

Clearly these statements have a lot of wiggle room. In your example an
argument can be made for keeping or breaking. BackLight and HeadLight make
more sense to me and probably will be easier for non-native English
speakers, but is it worth breaking the API for it, probably not. Another
factor is how long the API has been around and how widely used it is. These
all indicate how painful it will be to change the API which is half of the
cost/benefit decision.

I have added this to the FAQ.


Thanks
Ken