This extension does that mostly. The only problem is that it zooms linearly, so when you get closer it takes more input to scale the same amount. https://addons

This extension does that mostly. The only problem is that it zooms linearly, so when you get closer it takes more input to scale the same amount. https://addons.mozilla.org/en-US/firefox/addon/multi-touch-zoom/ https://addons.mozilla.org/en-US/firefox/addon/multi-touch-z... Also read the description: there's an option to enable it, but for me at least, it was too buggy to use.