Support zooming vertically/horizontally by dragging left/right or up/down on the respective axis

[damageboy]

Many modern charting/plotting UIs allow users to click on the axis (vertical/horizontal) and:

• drag up/down
  • for vertical axis
• left/right
  • for horizontal axis

I'd love for the plot to allow for an api, much like the existing allow_drag() api to enable axis zooming by dragging.
This should probably named in a descriptive way, something like: allow_axis_zoom_drag()

[damageboy]

Just updating that I have a PoC that kind of works, more or less. trying to iron out some issues there and will submit as a draft for review of the overall approach

[alexforencich]

I just checked how pyqtgraph does this - you can left click and drag to pan, and right click and drag to zoom, both on the axis (affects just that axis) as well as on the actual plot area (affects both axes).

[alexforencich]

Just got a chance to test this - it works great! Both via mouse and via multitouch. Thanks for making it happen!