With Firefox 29 just out, I’ve been testing it out as an alternative to Safari. However, if you’re new to Firefox you’ll probably find that the trackpad pinch and zoom gestures are not set by default. To turn them on, you’re going to need to do a bit of tinkering.

Open Firefox and type

about:config

in the address bar. Then type ‘browser.gesture’ in the search field and make the following changes to the ‘Value’ field for each of these preferences:

browser.gesture.pinch.in -> cmd_fullZoomReduce
browser.gesture.pinch.in.shift -> cmd_fullZoomReset
browser.gesture.pinch.out -> cmd_fullZoomEnlarge
browser.gesture.pinch.out.shift -> cmd_fullZoomReset
browser.gesture.pinch.latched -> false

Optionally you might want to also reduce the browser.gesture.pinch.threshold (I’ve got mine on 60).