[Webkit-unassigned] [Bug 145805] New: Unwanted vertical single-pixel gap appears between floated elements

[bugzilla-daemon at webkit.org]

https://bugs.webkit.org/show_bug.cgi?id=145805

            Bug ID: 145805
           Summary: Unwanted vertical single-pixel gap appears between
                    floated elements
    Classification: Unclassified
           Product: WebKit
           Version: 528+ (Nightly build)
          Hardware: Macintosh Intel
               URL: http://www.careyblyton.com
                OS: Mac OS X 10.10
            Status: NEW
          Severity: Normal
          Priority: P2
         Component: Layout and Rendering
          Assignee: webkit-unassigned at lists.webkit.org
          Reporter: Richard at Hallas.net

Created attachment 254576
  --> https://bugs.webkit.org/attachment.cgi?id=254576&action=review
Screenshot shows an unwanted vertical pixel gap where two abutting elements fail to touch together

Please visit http://www.careyblyton.com and view the 'breadcrumbs' (page location information) area that appears in the bottom-right corner of every page (white text on a blue background).

NB This problem is relatively trivial, but it's important because (a) it's fairly new misbehaviour (i.e. something that used to work correctly but no longer does), and (b) it has already propagated to the current releases of all the other WebKit-based browsers (i.e. Safari, Chrome, Opera etc.). In other words, the only mainstream browser (on the Mac) that still renders this page element correctly is Firefox, whereas it used to look as it should in all browsers.

The problem is that a vertical gap is appearing between two grouped elements. The 'breadcrumbs' component is made up of an area of white text on a blue background, which is floated to the right within the fixed-position group, and a small graphic to 'smooth' the text area into a decorative blue bar at the foot of the page; this small graphic is floated to the left of the text area.

The two elements should physically touch each other, such that they appear to create a single component. However, in recent releases of WebKit (including the current version 8.0.6 of Safari on Mac OS X 10.10.3), a single pixel's gap has started to appear between the two elements. This used not to happen, and I am not sure at what stage the problem started to appear. I have not as yet discovered a way to work around the problem by changing the CSS; adding extra borders or adjusting padding, for example, still results in the gap appearing.

Please note that the gap seems to be one pixel wide regardless of the screen resolution or scaling. For example, on my new iMac with Retina display, using a native 1x mode (e.g. 5120x2880) shows the gap as being one physical screen pixel wide. However, if I switch to my normal scaled screen mode (i.e. 2560x1440 in 2x detail), the gap is *still* one physical screen pixel wide - i.e. only 'half a pixel' in terms of the website itself and the (standard 72dpi resolution) bitmap graphics that it uses.

-- 
You are receiving this mail because:
You are the assignee for the bug.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.webkit.org/pipermail/webkit-unassigned/attachments/20150609/9f8154da/attachment-0001.html>