Improvements to ticking

The ticking system can use several improvements. Some of those concern the choice of ticks and some concern tick formatting:

• use label text dimensions to inform auto-computation of number of ticks. (#1669)
• allow users to specify hard values: min, max, exact numbers of ticks (#1670)
• allow users to specify explicit tick values (#1671)
• mechanism for semantic (re-)labeling of numeric tick values (#1672)
• allow some ticks to have “more detail”, e.g.: 12:37 :38 :39 :40 :41 (#1674)
• allow tick formats to be supplied (#842)
• documentation (#524)
• allow users to specify a suggested, desired number of ticks (#2185)

References: #1664

@bokeh/dev any additions to this list welcome

[bryevdv]

@cjw296 all the bullets in the issue have associated issues listed, and are checked off (or not). Minor ticks were not part of this group of suggestions, as best I can recall. There is a separate open issue for them though:

https://github.com/bokeh/bokeh/issues/2996

As stated there, the fact that months are uneven raises questions about the utility of minor ticks on a date time scale, or what even exactly they should do in all cases. But I am happy to consider a PR if someone else wants to scratch that itch.

[bernd-wechner]

Axis.major_label_policy

Thanks for the tip. Much appreciated. But indeed, poorly documented:

https://docs.bokeh.org/en/2.4.0/docs/reference/models/axes.html#bokeh.models.Axis.major_label_policy

Any tips on how to use it?