[FEATURE] Add fill properties to slope

It’d be useful to have an annotation like BoxAnnotation that creates a dividing line, but which can be angled. It’s possible to achieve something similar with an image, but then interaction is extremely slow as the plot has to re-render the image at every frame.

Using bands

This may be possible if we expand the features of the Band annotation. Currently, leaving lower or upper unspecified results in a blank figure, but we could change the behavior such that if either is unspecified the band continuous off infinitely.

I’d like to hear the thoughts of those more familiar with the capabilities of annotations.

[bryevdv]

I had forgotten Slope is configured with an intercept and derivative (instead of a point and an angle, say) so yes I agree it’s not possible to make a vertical slope, and that above/below are therefore well-defined always.

[graeme-hattan]

If you add above_fill_color and below_fill_color to Slope, then what is missing is the ability to fill between slopes like you can for horizontal/vertical lines using BoxAnnotation. Maybe a better solution is along the lines of adding gradient parameters to BoxAnnotation (then probably renaming the class to something more descriptive and then making BoxAnnotation a subclass which sets up horizontal/vertical borders).