Resize
That will be a handy feature. Curious as to whether non-proportional scaling is on the list too?
It’d be easy to add. Would non-proportional be useful to a lot of people? Every new control (a checkbox in this case) takes up space on everyone’s screen.
@Todd_Fleming Not sure how many people would benefit from it. A lot of graphics software does it via a simple padlock (or chain link) icon beside the dimensions box, so you can toggle it on & off. See screenshots below:
Adobe Illustrator Proportional Lock:
My idea (to minimise screen real-estate usage) is something like this:
https://plus.google.com/photos/115098100716537966732/albums/6357438279782399585/6357438278857841410
I like your last idea; it’s more clear than a lock icon and uses less space than a checkbox labeled “proportional”
Another thought I’ve just had to help you out with the whole screen real-estate issue is if you start having many options for this floating box, you may want to consider breaking it up into tabs something like this:
https://plus.google.com/photos/115098100716537966732/albums/6357446723775230801/6357446724234424050