HoverTool hit detection fails on vertical and near-vertical segment glyphs

Maybe I’m doing something wrong, but the HoverTool does not appear to work for segment glyphs that have vertical orientation.

from bokeh.plotting import figure

from bokeh.models import HoverTool

hover = HoverTool(tooltips=[

("index", "$index"),

("(x,y)", "($x, $y)")

])

p = figure(title=“Background Analysis”,

       toolbar_location="above",

       tools=[hover],

       plot_width=400, 

       plot_height=400)

p.segment(

x0=[1, 2, 3], 

x1=[1, 2.4, 3.1],

y0=[1, 2, 3], 

y1=[2, 2.5, 3.7], 

)

show(p)

I opened an issue on github, but maybe there’s a workaround or I’m doing something wrong?

Thanks,

Matt

Looking at the implementation:

  https://github.com/bokeh/bokeh/blob/master/bokehjs/src/coffee/models/glyphs/segment.coffee

I don't see anything offhand. But it's possible that:

* the third party spatial index we use (RBush) has a problem with vertical segments
* hittest.dist_to_segment has some obscure bug
* something else

It will require some investigation. If you have the ability to poke at it, I am happy to provide some debugging guidance. Otherwise it's probably not something that will be able to get a look until after the next release.

Some ideas for questions to answer that would provide additional useful information:

* does using tall, narrow quad/rect/vbar work?

* do vertical line or multilines work?

Answers to these questions could help narrow down where the problem actually is, and possibly provide a workaround in the immediate term.

Thanks,

Bryan