1138704 - Mouse-wheel zoom does not honour the toolkit.zoomManager.zoomValues preference

Status: NEW

(Core :: DOM: Events, defect, P5)

Description

[Luke Usherwood]

User Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:37.0) Gecko/20100101 Firefox/37.0
Build ID: 20150223185154

Steps to reproduce:

1. Using about:config, set 

 toolkit.zoomManager.zoomValues = .3,.5,.67,.8,.86956,1,1.1,1.2,1.33,1.5,1.7,2,2.4,3

2. Zoom out one 'click' using Ctrl+mouseWheel


Actual results:

Zoom level in the main menu shows as 90%


Expected results:

Zoom level in the main menu shows as 87%. This is the result if you use the main-menu zoom controls, or the keypress Ctrl+ -

Comment 1

[Luke Usherwood]

More info: this setting was particularly useful for me after upgrading to a new 2560x1440 monitor, as I needed to set Windows DPI scaling to 115% to read fonts comfortably. (Which I'm discovering Firefox handles very gracefully - nice work!)

Introducing the zoom level of .86956 'cancels' the DPI scaling, e.g. so that I can see bitmap images nice and crisply without scaling, which is often useful.

Comment 2

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

I think this code lives in EventStateManager::ChangeFullZoom.

Comment 3

[u279076]

I confirm this bug reproduces but it's not a bug introduced in Firefox 37. It reproduces back at least as far as Firefox 29. It probably goes back further but I'm not sure how to test this in pre-Australis builds.

Comment 4

[pallaswept]

Bump.

Comment 6

[Cristian Silaghi]

I just noticed this weird behavior and wanted to file a bug.

Hope that this bug reported 10 years ago will be fixed soon, it's quite annoying. 😞