446194 - 1 px jog with Firefox 3.01

Status: RESOLVED DUPLICATE of bug 446284

(Core :: Layout, defect)

Description

[Anthony Grace]

User-Agent:       Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.8.1.16) Gecko/20080702 Firefox/2.0.0.16
Build Identifier: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.8.1.16) Gecko/20080702 Firefox/2.0.0.16

The 3.01 version exhibits the bug know as the 1px jog when attempting to center an image on a page. The result is the placing of a border on one side of an image, such as a banner, etc. This bug did not appear in version 3.0.

Reproducible: Always

Steps to Reproduce:
1.
2.
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Comment 1

[Matthias Versen [:Matti]]

example URL or testcase please and if possible attached a screenshot to this bug.

Comment 2

[Anthony Grace]

Unfortunately I cannot provide a screen shot as I had to uninstall 3.01 and reinstall the 2.0 version (is there not an option to install 3.0?).

I spent hours agonizing  over this and nearly lost a client over it. A Google search gave me this:

http://support.mozilla.com/tiki-view_forum_thread.php?locale=de&forumId=1&comments_parentId=109927

So, I knew it wasn't just me! Sound like a rounding error when attempting to resolve something less than a pixel - when using the "margin: 0 auto;" to center-align an image in a page. This behavior was not present in 3.0.

Sorry I can;t offer more evidence than this but it should be very easy to reproduce for someone with 3.01 installed:

http://www.pmob.co.uk/temp/onepxjog.htm

Comment 3

[Tyler Downer [He/Him]]

Attachment: Screenshot of problem

This shows the website in question with Mozilla/5.0 (Windows; U; Windows NT 6.0; en-US; rv:1.9.1a1pre) Gecko/2008071903 Minefield/3.1a1pre on Vista.

Comment 4

[Vladimir Vukicevic [:vlad] [:vladv] (needinfo me, slow to respond)]

Layout guys, is this an actual bug?  Or just unintended effect?

Comment 5

[Anthony Grace]

Well, since it's Firefox it must be an "unintended effect"; it would only be a bug if is was IE? :-O

Comment 6

[Vladimir Vukicevic [:vlad] [:vladv] (needinfo me, slow to respond)]

No, I mean an unintentional result of changing the way layout happens internally; that is, it might not actually be a bug, but correct as per the spec.  Firefox 3 changed the way internal layout was computed, partly to support full-page zoom; presumably IE7 had to do something similar.

Comment 7

[Anthony Grace]

lol :-) Either way, it now involves the hack of adding 1px to the body tag. Hacks are unacceptable since they cause sites to break at a later stage. You make a very interesting point though regarding the zoom. IE7 works just fine; IE8 is not ready for prime time yet and I also had to uninstall it.

Hopefully, his can be fixed. I was very impressed with Firefox 3 and noticed the speed increase straight away :-)