Slide viewer

[iamleeg]

Fixes #4. I'm putting this up early because I'm going to need to introduce broad changes to make it work and want to get early feedback. Particularly, I'm introducing an abstract parent of sight::SlideData so that I don't need to work with real openslide files in testing.

[martinjrobins]

Thanks @iamleeg. I'm happy with the abstract Slide class, very handy for testing.

So the Model class would bundle up an internal representation of everything that would eventually be passed onto the View to render, correct? This would include the slide data, current viewport onto the slide, including zoom level, any overlay data that we put on top etc.

[iamleeg]

I think that's mostly correct, but the distinction may be closer to this:

• The Model contains what is drawn: slide data, overlays, etc.
• The View contains how it's drawn: so the viewport and zoom come from here.

Some Qt views use delegates to supply the "how" and it may make sense to introduce that separation later, but I think there's enough separation between the data being drawn and the configuration of the view that they don't both belong in the same model class.