Catching Mac trackpad zoom

Question

Currently in my application i am catching the mouse wheel events and perform zoom in or out on a Canvas element. If user uses Mac and tries to perform zoom with the trackpad, there is no event and what actually happens is zoom in/out of browser.

Is there a way to catch the zoom event performed with the trackpad?

Answer 1

At least in Chrome, trackpad "pinch-to-zoom" triggers a wheel/mousewheel event that appears as though the ctrl key is pressed. You can capture this event just like any other wheel/mousewheel event and prevent its default from occurring. Here is an example using jQuery:

$("canvas").on("mousewheel", function(e) {     if (e.ctrlKey) {         e.preventDefault();         e.stopImmediatePropagation();          // perform desired zoom action here     } });