Bad tooltips positioning when container has the CSS zoom property != 100%.

[meronz]

Description

When showing a chart in a container that has the zoom property set to something different than 100%, the tooltips on the line chart do not follow the mouse pointer properly. I suspect this is a problem that also occurs on other features that rely on the pointer feature. I reproduced this behavior on Line, Area, Pie charts but there could be more.

Steps to Reproduce

1. Render a chart in some div
2. Apply zoom to 50% to said chart's parent
3. Move the mouse over the line chart

Expected Behavior

The tooltip is shown on the point closest to the mouse pointer.

Actual Behavior

The tooltip position is skewed to the left when zoom is less than 100%, to the right when zoom is more than 100%.

Screenshots

Reproduction Link

https://codepen.io/meronz/pen/ByyXjrj