778055 - The background is much larger then the actual page for bbc.co.uk in persian

Status: NEW

(Core :: Layout, defect)

Description

[Adrian Tamas (:AdrianT)]

Firefox Mobile Native 15.0b2 build 1/ Nightly 17.0a1 2012-07-26
Device: HTC Desire (Android 2.2)

Steps to reproduce:
1. Go to http://www.bbc.co.uk/persian/mobile/index.shtml
2. Zoom out as far as you can

Expected results:
Since this is a mobile page the user should not be able to zoom out

Actual results:
The background is a lot larger then the page extending to the left and bottom (since the page is an RTL page). This causes issues with the thumbnails for the tab menu and about home also.
Font inflation does not have any effect on the page. The size of the background is the same with the text set to tiny or extra large.

Note:
The issue is not reproducible using the default Android Browser.

Comment 1

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

The page renders the same in Fennec as it does on desktop, with the extra margin on the left.

Comment 2

[Lawrence Mandel [:lmandel] (use needinfo)]

kats - As adrian reported in comment 0, this issue is not present in the Android stock browser. I can confirm that it is not an issue in Chrome either. In both of those cases I can zoom in but cannot zoom out past the default page size. Do you know what is different in the Firefox case?

Comment 3

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

According to Ehsan's comment at https://bugzilla.mozilla.org/show_bug.cgi?id=748384#c0 this is caused by the image with class "web_bug" which is positioned at -1000px. I'm not sure why this doesn't happen in Chrome or the stock browser (or Safari/Chrome on desktop either). I guess it might be a core Gecko problem rather than an evangelism issue, not really sure.

Comment 4

[Lawrence Mandel [:lmandel] (use needinfo)]

Over to core for analysis and comment.

Comment 5

[Boris Zbarsky [:bzbarsky]]

Attachment: Minimal testcase that shows a behavior difference with WebKit

Comment 6

[Boris Zbarsky [:bzbarsky]]

So what happens here is that WebKit won't let you scroll up, ever.  Neither will we.

It _will_ let you scroll to the left, if the body or root is rtl.  But only if the things that are to the left of the viewport vertically overlap the viewport.  Otherwise it won't.

The only behavior difference from Gecko here is the "vertically overlap the viewport" condition.

Actually, the rtl bit is a bit of a red herring.  Attaching a testcase that does not depend on that.

So the real question is whether content completely above the viewport should trigger overflow to the side as needed...  That's the behavior this site seems to depend on.

Comment 7

[Boris Zbarsky [:bzbarsky]]

Attachment: Even more minimal

Comment 8

[Robert O'Callahan (:roc) (email my personal email if necessary)]

Opera and IE behave the same as us.

Excluding stuff that's vertically above the viewport seems unnecessarily complex. This seems like a Webkit/site bug to me.

Comment 9

[Andrew Overholt [:overholt]]

Is this still reproducible?

Comment 10

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

Yup, this still reproduces on desktop as well as on Fennec. The two test cases attached to this bug scroll in Firefox but not in Chrome/WebKit

Comment 11

[Andrew Overholt [:overholt]]

Thanks, kats.

Boris, what should we do here?

Comment 12

[Boris Zbarsky [:bzbarsky]]

Probably get the actual behavior here standardized one way or the other?  If it is, and we're following the spec, file bugs on Chrome/WebKit and presumably evangelize the site.

Comment 13

[Andrew Overholt [:overholt]]

Jet, anyone on your team interested in comment 12? I already asked a few people and the response was "I don't know enough about CSS to be of use."

Comment 14

[Jet Villegas (inactive)]

(In reply to Andrew Overholt [:overholt] from comment #13)
> Jet, anyone on your team interested in comment 12? I already asked a few
> people and the response was "I don't know enough about CSS to be of use."

Not really. It appears that the affected BBC site was repaired some time ago:
http://www.bbc.co.uk/persian/mobile/index.shtml

I agree with roc (comment 8) that excluding the out-of-bounds content above the viewport is unnecessarily complex, especially now that we don't have a top-site depending on this behavior. That is, I'm not sure I'd bother to change this even if the spec didn't go our way.