What unit does domainPadding use? Pixels or domain units?

[balazs-edes]

I'm trying to make a Line+Area chart with a label on the lowest and the highest point of the chart, that looks like this:

I'm trying to add a fixed amount of space above and below the domain (the area where chart-points are drawn), so no matter what I have enough space to draw the label.

First I tried padding, the issue with this, is that whatever is drawn in the padding are, it's simply clipped:

Next I tried to use domainPadding, which kind-of works, but I'm not really sure what the units are. For example if I give the chart domainPadding={{ top: 20, bottom: 20 }}, there are sometimes points in the points array that are in the top 20 or bottom 20 pixel relative to the chartBounds, so if they were pixels, the padding is not respected.

If domainPadding is not in pixels, what is the best way, to gain a fixed amount of drawable space on the top and bottom of the chart?