1655223 - default zoom at 133 causes the zoom step down and up to be 123 and 113 and so on

Status: NEW

(Firefox :: Settings UI, enhancement, P3)

Description

[emailsaddres]

User Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Firefox/78.0

Steps to reproduce:

set default zoom at 133 in preferences.
zoom in or out in any page.

Actual results:

the zoom stepdowns and ups are 10% so the new zoom levels are 143 133 123 113 103 and so on.

Expected results:

zoom levels should have been the defaults :100 110 120 133(or 130) 140 150.

maybe the issue is easily fixable by using the default page zooms (100 110 120 130 140 150) instead of (100 110 120 133 150)

Comment 1

[Simona Badau, Desktop QA]

I can confirm that this issue is reproducible, reproduced it on the latest Nightly 81.0a1 on Ubuntu 18.04 x64.

If I set the preference Default Zoom to 133% and I zoom in and out by pressing Ctrl key and the mouse wheel, the zoom levels are 113, 123, 133, 143, 153. But If I zoom in and out by using the key combination Ctrl++ or Ctrl-- or the buttons (-/+) from the open menu door0-hanger then the reached zoom levels are: 110, 120, 133, 140, 150.

Comment 2

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

This is in the browser frontend.

Comment 3

[Mike Conley (:mconley) (:⚙️)]

We triaged this today, and we wonder why 67% and 133% are even offered as options in the default zoom menu list. Why aren't the options all multiples of 10?

Comment 4

[Jared Wein [:jaws] (please needinfo? me)]

https://bugzilla.mozilla.org/show_bug.cgi?id=401221 is what introduced the values that are in use today. This was regressed by bug 1516413. Brad, can you take a look at this?

Comment 5

[Brad Werth [:bradwerth]]

This is expected behavior. Mousewheel (or command-scroll) zooming has been in increments of 10% for awhile, I think. I just checked and this was true at least as far back as Firefox 66 (early 2019). If you use menu or keyboard shortcuts to get to a specific zoom level, mousewheel zooming will get you increments of 10%.

Comment 6

[Jared Wein [:jaws] (please needinfo? me)]

Okay, thanks for the background. That doesn't mean that there isn't a bug here though. There is nothing that explains to the user that the increments will be different for mouse vs keyboard changes, and the min/max bounds are the same for mouse and keyboard (30% and 300%). Mousewheel should just use the same steps that are defined by https://searchfox.org/mozilla-central/rev/72a1334982cadde0ca8b3d3583877afea80f5639/modules/libpref/init/all.js#3761

Comment 7

[Brad Werth [:bradwerth]]

Alright, we can make it work as you propose.

Comment 8

[Brad Werth [:bradwerth]]

Since changing this will involve changing behavior for Firefox, for extensions, and for Thunderbird, I'm making this bug dependent on the landing of the web extension support in Bug 1634556. When that lands, we can change the events and event listeners all at once.

Comment 9

[Brad Werth [:bradwerth]]

I've got to prioritize other work. Taking myself off.