[matplotlib-devel] wrote a selection bar widget (attached)

[Egor Z. <ez...@gm...>]

Dear matplotlib devels,

I wrote a selection widget someone else might find useful. The widget is 
based on the slider widget.

Things I implemented:
* blitting (bar still flashes once when clicked on, sorry about that!)
* Horizontal or vertical direction
* Multiple selection bars on a figure
* interaction between two bars to set a range

Things I struggled with:
* When a bar is dragged towards one of the figure edges too quickly, it 
gets stuck in its last recorded position on the graph (that should be 
the figure edge).
* Don't know how to change the mouse pointer when on top of the bar (the 
<-> pointer for a vertical bar would be nice)
* Don't know how to define a range in pixels around the bar (for 
grabbing), so used 0.01 of the full range instead
* Haven't implemented dragging when a bar reaches the other bar (set 
with set_barmin or set_barmax) but hasn't reached the limit of its range.

How to test:
have mplbar.py and test_bar.py in the same directory, launch test_bar.py


Hope this all makes sense (somehow I doubt it). And like I said, if you 
guys like it or want to adapt it further, please do, the code this is 
based on is yours after all!

Regards,
Egor