feature request: scale extents a bit more than the absolute fit

Right now:

hv.Scatter([[-1,-1], [-1, 1], [0, 1], [1,1]])

gives points that you cannot even see:

Preferably the plot would take the extent and make it 10% bigger or so, like:

hv.Scatter([[-1,-1], [-1, 1], [0, 1], [1,1]])[-1.1:1.1, -1.1:1.1]

which does show the points:

[philippjfr]

I assume the diff will be to set this value to 0.05

Not sure, I usually use 0.1 for 5% padding on each end.

[philippjfr]

Agreed, this is something we should have added a long time ago. All our plots should automatically pad the axis ranges by a few percent. The question has always been how precisely the padding is calculated. Is it a fixed 10% or is there special handling around zero? Other plotting libraries have had this discussion (see https://github.com/matplotlib/matplotlib/issues/4891) and have generally settled on a fixed 4-5% padding along each axis:

The easiest way to handle this is to simply ensure that the axis limits are slightly larger than necessary to cover all the data, and then leave it at that. It avoids the really nasty cases, avoids surprises, and if people want something fancier than they almost always have to tweak the limits by hand anyway. As further evidence that this works, this is what R does and it basically just works – no-one complains.

Specifically, base R calculates default axis limits by: taking the min and max of the data, and then setting the limits 4% further beyond each of those. ggplot2 uses a similar algorithm, but uses 5% by default. (See here, semantics of expand= is (multiplicative expansion, additive expansion).)

If we agree with both matplotlib and ggplot2 (and bokeh?) that’s what we can use by default as well. It’s trivial to do and I strongly believe this belongs in 1.7 as part of changing our global styling defaults (https://github.com/ioam/holoviews/issues/823).