Bubble chart axis padding and elastic axes

[neverfox]

It seems that a percentage setting for axis padding doesn't work as expect (or else I'm not clear on how it's calculated). When setting a % padding for an axis on a bubble chart, the padding doesn't appear to be symmetrical (higher on the high numeric end) as it is with a fixed number. Also, when filtering the lower numeric end of the axis seems to lose any padding.

[neverfox]

I think what's happening is that the percentage is being calculated separately for the min and max rather than being a single percentage calculated from the range. I haven't confirmed this but that would explain what I'm seeing. Say the smallest x value of a bubble is 1m and the highest 4m. With a 100% padding, the left padding is 1m and the right is 4m.

What I expected was that if the range of values is from 1m to 4m, and I set a 20% padding, there would be a padding of 600,000 on each side. Optimally, of course, I'd like to see a radius-based padding, but I believe that's already been broached.

[gordonwoodhull]

It would be great if you could submit a failing test for this, or at least a fiddle.

Somewhere or another I documented that the correct (absolute) padding gets added but the offset is wrong, so the clip rectangle has the right size but is aligned with the upper left instead of padding all sides. I didn't look at %-based padding though.

It would be easiest to fix this along with #440 / #603.

[neverfox]

I will look into creating a jsfiddle or jsbin for this. Thanks.