fiveNinePlusR Reporter
	Description • 6 years ago

macOS and iOS have a smart zoom feature for their trackpad and magic mouse peripherals where you double tap without clicking and it zooms in and out of the main content feature that you double tap on. for example, double tapping on a paragraph of text will zoom and center the window to that section of text. double tapping again would reset the zoom back out. I have seen this implemented in chrome and safari on macOS and safari on iOS.

At the very least it would be nice to prevent the double tapping from resetting the zoom back to 100% when zoomed in to a different zoom level when that preference is switched on. 

Description of the feature:

https://support.apple.com/en-us/HT204895

	Botond Ballo [:botond]
	Comment 1 • 6 years ago

(In reply to fiveNinePlusR from comment #0)
> At the very least it would be nice to prevent the double tapping from
> resetting the zoom back to 100% when zoomed in to a different zoom level
> when that preference is switched on. 

Are you talking about a current behaviour of Firefox here? If so, can you clarify what preference you mean?

	Botond Ballo [:botond]
	Comment 2 • 6 years ago

(Double-tap-to-zoom on Mac is tracked in bug 674371, so that part is a duplicate.)

	fiveNinePlusR Reporter
	Comment 3 • 6 years ago

> Are you talking about a current behaviour of Firefox here? If so, can you clarify what preference you mean?

Yes, it's current behavior in firefox. The preference is called smart zoom on mac and when it's enabled the double tap will zoom to 100%.

It looks like the other part is a dupe of that bug in comment 2.

	Botond Ballo [:botond]
	Comment 4 • 6 years ago

(In reply to fiveNinePlusR from comment #3)
> Yes, it's current behavior in firefox. The preference is called smart zoom
> on mac and when it's enabled the double tap will zoom to 100%.

Markus, can you reproduce this? Is it Mac widget code responding to the double-tap?

	fiveNinePlusR Reporter
	Comment 5 • 6 years ago

for the built in trackpad the gesture is a double tap with two fingers. for the magic mouse it's a double tap with one finger. i have also tried to make it happen with that preference disabled and it will not reset the zoom so it's definitely that preference causing an issue.

	Kartikaya Gupta (email:kats@mozilla.staktrace.com)
	Comment 6 • 6 years ago

This gets handled at [1] in the widget code and then I think by the frontend code at [2]. So to implement smart zoom we'll need to wait until APZ zooming works on desktop. But to disable the current behaviour (which I can reproduce) we'd want to make changes to the front-end code somewhere, probably after UX consultation. So it's better to file another bug for that issue.

[1] https://searchfox.org/mozilla-central/rev/d850d799a0009f851b5535580e0a8b4bb2c591d7/widget/cocoa/nsChildView.mm#4161
[2] https://searchfox.org/mozilla-central/rev/d850d799a0009f851b5535580e0a8b4bb2c591d7/browser/base/content/browser-gestureSupport.js#101

	Kartikaya Gupta (email:kats@mozilla.staktrace.com)
	Comment 7 • 6 years ago

Actually since the double-tap support is tracked by bug 674371, let's use this bug for disabling the current behaviour if desired.