bokeh: [BUG] HoverTool in 'vline' mode doesn't work with vertical segments

Bokeh version: 1.4 Python version: 3.7.5 Browser: Firefox / Chromium OS: Linux

When adding a HoverTool with mode='vline' to a plot with vertical segments, the tooltip is not displayed.

Example code:

from bokeh.io import output_file, save
from bokeh.models import HoverTool
from bokeh.plotting import figure

x = [1, 2, 3, 4]
y0 = [1] * 4
y1 = [2] * 4
fig = figure(tools=[HoverTool(mode='vline')])
fig.segment(x, y0, x, y1)
output_file('vline.html')
save(fig)

Screenshot:

About this issue

Original URL
State: closed
Created 5 years ago
Comments: 19 (17 by maintainers)

Most upvoted comments

OK well let’s make a PR and go from there (the other reason to make a PR earlier is that it is much easier for other people to try out a PR)

bryevdv on Mar 18, 2020

@kumaran-14 the span coordinate geometry comes in as pixel coordinates. You can see that scale invert function is use to convert to back to “data space” (so that the spatial index an be used to get a first batch of potential hits). Scales also have a compute method, which goes in the opposite direction, converting from data space to pixel space. You can use that to convert segment data coordinates to pixel coordinates in a similar way, for the final comparison.

bryevdv on Feb 23, 2020

@kumaran-14 perhaps the comparisons can be changed to be in “pixel-space” instead of “data-space”? In which case a fixed epsilon of e.g. 0.5 (of a pixel) on either side might be sufficient.

bryevdv on Feb 20, 2020

@kumaran-14 Any one can take up any issue they please 😃 I think it would be great if you are able to look in to this. Specifically, the hit testing for Segment glyphs agains “spans” (e.g. a vline or hline) is here:

https://github.com/bokeh/bokeh/blob/master/bokehjs/src/lib/models/glyphs/segment.ts#L95-L124

That’s probably what would need to be modified.

bryevdv on Feb 13, 2020