Thanks for the PR! 😃

However, I'm concerned that the X-position code isn't getting the same changes. Why does this only affect the Y-position?

@timmywil I think X-Position has some issues as well. Unfortunately I didn't take a look at it yet but from general testing I can see a bunch of issues.

I just pushed another fix:

1. Add a handle to invert, and automatic containment.
2. Handle container border.

@timmywil updated the source code to support x-axis position. Please take a look.

I think the code handles this but I don't know the actual cases that this code was written for:

if (this.$parent.css('textAlign') !== 'center' || $.css(this.elem, 'display') !== 'inline') ...

I'm using this patch now. Latest version had this bug, so I was using an older one (that had another bug), so now I've got everything working at once. Please pull 🕺

@timmywil if the test fixed, will you merge this?

Without this fix contain: 'invert' does not work for me.

For instance an image that should move between 0px and -360px instead moves between 180px and -180px. The effect is that the panned image has an empty 180px margin on the top side.