1392361 - OS X trackpad pinch gesture (or ctrl+two-finger-pan) on PDF changes zoom like crazy

Status: RESOLVED FIXED

(Firefox :: PDF Viewer, defect, P3)

Description

[Kartikaya Gupta (email:[e-mail])]

Load any PDF, e.g. https://www.library.yorku.ca/spark/books_journals_more/PARCA%20Test_Final.pdf on a macbook, and use a "pinch" gesture on the trackpad.
Expected: PDF zooms in or out gradually
Actual: PDF zooms in or out very much, quickly jumping to 1000% or down to 25%

I can repro on release, Beta and Nightly.

Comment 1

[Kartikaya Gupta (email:[e-mail])]

I'm running mozregression to find out when this happened.

Comment 2

[Yury Delendik (:yury)]

(In reply to Kartikaya Gupta (email:[e-mail]) from comment #0)
> ... and use a "pinch" gesture on the trackpad.

By default, locally I can only zoom in/out a web page or PDF using Cmd+two-finger-scroll, and not using pinch. Can you provide more details how to setup "pinch" gesture on the trackpad and Firefox?

Comment 3

[Kartikaya Gupta (email:[e-mail])]

Regression window is this:

https://hg.mozilla.org/integration/mozilla-inbound/pushloghtml?fromchange=1944785ec6254237f1425dc35f873951c7716d39&tochange=134875c28871d8c8f2538c4cb1507f2e37b0713e

Prior to this bug, the pinch action had no effect at all. After this bug, the pinch effect controls zooming but is far too sensitive to small pinch gestures.

Comment 4

[Kartikaya Gupta (email:[e-mail])]

(In reply to Yury Delendik (:yury) from comment #2)
> By default, locally I can only zoom in/out a web page or PDF using
> Cmd+two-finger-scroll, and not using pinch. Can you provide more details how
> to setup "pinch" gesture on the trackpad and Firefox?

There's really nothing I did in Firefox itself to set this up. It happens on a clean profile for me. Maybe OS X settings? Try checking if the "Zoom in or out" option in OS X settings -> Trackpad -> Scroll & Zoom is enabled.

Comment 5

[Markus Stange [:mstange]]

macOS trackpad scrolling while pressing Ctrl is also very sensitive on pdf.js. So this was a pre-existing issue in the way pdf.js handles zoom wheel events, it's just exposed in a different way now.

Comment 6

[Yury Delendik (:yury)]

(In reply to Kartikaya Gupta (email:[e-mail]) from comment #4)
> (In reply to Yury Delendik (:yury) from comment #2)
> > By default, locally I can only zoom in/out a web page or PDF using
> > Cmd+two-finger-scroll, and not using pinch. Can you provide more details how
> > to setup "pinch" gesture on the trackpad and Firefox?
> 
> There's really nothing I did in Firefox itself to set this up. It happens on
> a clean profile for me. Maybe OS X settings? Try checking if the "Zoom in or
> out" option in OS X settings -> Trackpad -> Scroll & Zoom is enabled.

Nope. "Zoom in and out - Pinch with two finger" is enabled for me in the settings, but no such gesture in FF.

Comment 7

[Kartikaya Gupta (email:[e-mail])]

(In reply to Markus Stange [:mstange] from comment #5)
> macOS trackpad scrolling while pressing Ctrl is also very sensitive on
> pdf.js. So this was a pre-existing issue in the way pdf.js handles zoom
> wheel events, it's just exposed in a different way now.

Good point, I also see this behaviour. It's just easier to hit now I guess, because the pinch gesture is more natural (at least for me) to use. I filed https://github.com/mozilla/pdf.js/issues/8802 for it.

Comment 9

[Kartikaya Gupta (email:[e-mail])]

PR to fix: https://github.com/mozilla/pdf.js/pull/12203