Pie chart label cut off when container has a particular height and multi-line data-labels are used

[HendrikThePendric]

Expected behaviour

The data label is either be fully visible, or completely hidden.

Actual behaviour

There is an intermediate state when the data-label is partially visible and partially hidden (i.e. the label is cut off).

In the screenshot below I show this intermediate state: the CHC label also has a number and percentage below it, but these are not visible / are cut off.

Live demo with steps to reproduce

1. Go to my JSFiddle
2. Increase/decrease the height of the container until the bottom data label becomes partially visible (this is around 170-180px)

Product version

Highcharts Core 11.4.8

Affected browser(s)

All

Additional notes

• I discussed this problem with a Highcharts support engineer (Michal) and he agreed that this was a bug although probably not very high urgency, because it only occurs under very specific circumstances
• I found a previous issue Pie data labels get cut off when using multiline data labels  #17286 that seemed identical at fist glance, but I actually think in the end that case the problem was caused by a configuration error (rigidly setting the chart size to 100%).

[TorsteinHonsi]

Thanks for reporting! I agree it's a bug. The data labels should not be allowed to go outside the plot area (silver line), at least not this far.

Minimal reproduction

https://jsfiddle.net/highcharts/nt0qa289/

[TorsteinHonsi]

After some digging, I concluded there are two problems:

1. The distribution inside the plotHeight does not work correctly. The lower label should stay within the bounds. The code in question is in the drawDataLabels function.
2. When we have large slices like this, with so much available space on the side, the label should gravitate towards the side rather than at the bottom.

In the PR, I address the second issue. This will resolve most, but not all, manifestations of the first issue. View the OP demo with the fix applied at jsFiddle @HendrikThePendric .