Graph: Place the Y grid dynamically if there is no scale

[mpikzink]

Place the Y grid dynamically based on the graph's Y range. The algorithm ensures that you always have a grid, that there are enough but not too many grid lines, and that the grid is metric. That is the grid lines are placed every 1, 2, 5 or 10 units. This parameter will also ensure that you get enough decimals displayed even if your graph goes from 69.998 to 70.001.

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[PipoCanaja]

LGTM

[PipoCanaja]

Thx @mpikzink !

[fcqpl]

Hi @mpikzink,
Your commit broke Y grid on our LibreNMS instance.
Before:

After:

Could you please check this?

[PipoCanaja]

Hi @mpikzink, Your commit broke Y grid on our LibreNMS instance. Before: After:

Could you please check this?

Hi @fcqpl
Please let us know exactly which page you have this display ?

[fcqpl]

Hi @PipoCanaja,
This is from dashboard graph "Manual ports", which is linked to /graphs/id=6562585,6562588,6562603,6562606/type=multiport_bits_separate
Same with "Overall Traffic", "Memory" in Device overview.

[mpikzink]

Thanks for your hint, I can also reproduce it. In some cases, the rrdtool option seems to have other grid label ratio, which is not configurable. I try to look in the sources of rrdtool. Perhaps I find a better solution which solve both issues. I haven't found some in the manuals, yet.