Closed Bug 134942 Opened 23 years ago Closed 2 months ago

[meta] single pixel rounding error tracking bug


(Core :: Layout, defect)






(Reporter: contact2009, Unassigned)


(Depends on 10 open bugs)


(Keywords: meta)

This will be a tracking bug for the many bugs that are _potentially_ duplicates
of one another. In any case, these bugs are definitely related to each other, at
least in their symptoms.
Please feel free to remove and add bugs to the dependency list.

It's likely that all these reported problems are caused by one or two bugs that
are rounding errors. Adding keyword qawanted to try to narrow the issues.
Depends on: 132164
Depends on: 119824, 121230, 130084, 132930
A recently fixed bug in this area is bug 83289. 

Depends on: 116636
Thanks. Adding.
Depends on: 35735, 131382
I can't find the bug number now, but there used to be one for the scrollbar
"thumb" being drawn wrong.  That was sort of fixed, but once in a while, the
vertical scrollbar thumb leaves a 1 pixel gap at the bottom.
Depends on: 80292
Maybe that is bug 80292. 
Depends on: 125560
Depends on: 37589
Assignee: chofmann → xah
Depends on: 138431
No longer depends on: 138431
Depends on: 133133
Depends on: 129915
Depends on: 65691
Depends on: 143820
No longer depends on: 119081, 143820
Adding bug 147547.
Depends on: 147547
Depends on: 96531
Depends on: 147845
Depends on: 56876
*** Bug 147453 has been marked as a duplicate of this bug. ***
Depends on: 152671
Depends on: 154467
Keywords: mozilla1.0
bug 130767 should be added to this list
Target Milestone: --- → Future
Depends on: 130767
Depends on: 140122
No longer depends on: 154467
I don't have time to keep this up to date anymore. If someone wants to maintain
it, please take it over. Thanks.
Assignee: xah → nobody
Depends on: 165950
Depends on: 174977
adt: removing nsbeta1 nomination; nominate bugs indiviually as appropriate.
Keywords: nsbeta1
This seems most closely related to bug 147453, although I'm not certain which
one it falls under, so putting this in the tracker.
Seeing this, no matter what DPI I seem to use, in varying levels of severity,
irregardless of font.
However, smaller fonts, unsurprisingly, hide the rounding error.
for example, I see things like this:  (that was a size 13 Tahoma)

Tried a range of DPIs, from 85 to 120, a number of fonts in various sizes, and
only tended to vary the amount of white showing until I drop below a critical
font size.
For above page, fonts ~<11 display the page fine on my machine, those above,
mess it up.

Windows 2000 SP3 running a nightly from 2003-04-18
Adding some bugs which I found to be depending from this meta-bug.
Depends on: 131444, 175746, 176706, 214100
Depends on: 224753
Depends on: 118946
Depends on: 131187
I added bugs 135012, 136012, 172162, 171282, 217313, 217825. They are all
related to font corruption by one pixel shifts.

Like many here I believe that all or most of these bugs are either caused by the
same underlying problem, or are extremely closely related. However, the
descriptions are sufficiently different (some talk about only scrolling causing
the problem, some seem to be fixed by special display resolutions, etc.) that
I'm hesitant to close them as duplicates, in order to not 'lose' important
possibly useful debug information that has accumulated in all of the bugs.
Depends on: 135012, 171282, 172162, 217313, 217825
CC'ing and, since they are QA contact and
assignee for many of the individual bugs in the dependency list. Perhaps
knowledge of other, related bugs is in any way useful for them.
Depends on: 227483
Depends on: 206631
Depends on: 229734
Depends on: 230573
Depends on: 138115
No longer depends on: 138115
Depends on: 250051
Just to add to the slantastic problem in an interesting way.
This demo seems to render fine in Mozilla under windows.
Under linux, regardless of what font size I choose, I get white lines appearing
randomly throughout the demo.
Depends on: 254214
Depends on: 255115
Depends on: 261964
Bug 98564 ("caret overlaps the last character in textfield - if positioned after
the last char") may also be related.

Depends on: 293967
Blocks: 244367
No longer blocks: 244367
Depends on: 244367
Depends on: 295781
*** Bug 295823 has been marked as a duplicate of this bug. ***
Depends on: 298219
Depends on: 313543
Depends on: 303558
Depends on: 305497
Depends on: 307505
Hi Thomas. The bugs you mentioned are all blocking this tracking (or meta) bug. You can see this at the top of the bug entry under "depends on". As the name indicates, its meant to ease keeping track of pixel rounding bugs. Probably one of those dependant bugs covers your testcase. And you can always check whether the latest nightly builds (, back up your profile!) still expose the issue at hand.
I totally overlooked the "Depends on" section, sorry about that. I need sleep. I just assumed the bug basically only needed to be fixed in one location, not separately for so many different cases. Thanks for clearing that up.

I'm already running Minefield, and actually suffer from the rounding bug on my personal site, which is why I'm interested. So yes, my test case still shows the bug in the latest nightly.
I just thought I'd point out I just noticed the rounding errors I experienced are now gone in the latest trunk builds. The testcase I posted above ( also works fine now. I thought this was surprising, as none of the rounding bugs got marked as fixed recently.
Depends on: 599630
Depends on: 787437
Bug 375240 seems related.
Depends on: 923416
Went through the dependency list and updated the bugs where possible.
Keywords: qawanted
Marking all tracking bugs which haven't been updated since 2014 as INCOMPLETE.
If this bug is still relevant, please reopen it and move it into a bugzilla component related to the work
being tracked. The Core: Tracking component will no longer be used.
Closed: 8 years ago
Resolution: --- → INCOMPLETE
Product: Core → Core Graveyard
Component: Tracking → Layout
Product: Core Graveyard → Core
QA Contact: chofmann
Resolution: INCOMPLETE → ---
Summary: single pixel rounding error tracking bug → [meta] single pixel rounding error tracking bug

I believe bug I noticed may be classified to belong here.
I am experiencing a bug when triangular svg:

<svg width="684.6" height="17.6" class="inclined right" version="1.1" viewBox="0 0 181.1 4.657" xmlns=""><path d="m181.1 0v4.657h-181.1z" strokewidth="1.604"></path></svg>

is placed above square div content, one pixel line appears between the two.

Bug is present on desktop browser Firefox for developers, 90.0b3 (and earlier versions)
In other desktop browsers, i.e., Chrome, Edge, bug does not appear, i.e. there is no 1px line between svg and div box.

When I tweak svg (i.e. set d attribute to d="m181.1 0v4.7h-181.1z"), 1px line disappears. It is clearly some sort of a rounding problem.

Severity: normal → S3

closing as we haven't been using it for a while

Closed: 8 years ago2 months ago
Resolution: --- → INACTIVE
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