Open Bug 422679 Opened 17 years ago Updated 2 years ago

Firefox renders top and bottom borders different, resulting in unintended results with overlapping borders

Categories

(Core :: Layout, defect)

defect

Tracking

()

People

(Reporter: fischer.sebastian, Unassigned)

References

Details

(Keywords: regression, testcase)

Attachments

(4 files, 1 obsolete file)

User-Agent:       Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10.4; en-US; rv:1.9b5pre) Gecko/2008031304 Minefield/3.0b5pre
Build Identifier: Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10.4; en-US; rv:1.9b5pre) Gecko/2008031304 Minefield/3.0b5pre

The new way of rendering borders makes the shared (dotted) border between two objects look like it was solid (at least when set to 1px). This does not happen with border-style: dashed.

Possibly related: #379303

I'm going to upload a testcase for this.

Reproducible: Always

Steps to Reproduce:
n/a
Actual Results:  
The shared border (border-bottom of the upper div and border-top of the lower div), both styled as 1px dotted, is rendered as if it was solid.

Expected Results:  
Border is being rendered dotted.
Attached image actual result (deleted) —
Attached image expected result (deleted) —
Attached file testcase (obsolete) (deleted) —
Attached file testcase (deleted) —
Attachment #309128 - Attachment is obsolete: true
Confirmed on Windows XP, latest trunk. 
This regressed in the last days of April 2007, so this is probably a regression from Bug 368247.
Blocks: 368247
Status: UNCONFIRMED → NEW
Component: General → Layout
Ever confirmed: true
Keywords: regression
OS: Mac OS X → All
Product: Firefox → Core
QA Contact: general → layout
Hardware: Macintosh → All
Version: unspecified → Trunk
Keywords: testcase
Attached file testcase II (deleted) —
as of today, i can't reproduce the bug with the above testcase, but this one (using an unordered list) still shows the bug.
I'm not sure this should be considered a bug -- I don't think we've ever made promises that dotted borders will always start at the same offsets or something across the entire page (nor does CSS require us to).  Since the borders are explicitly overlapping here, the solid line is indeed unintended, but shouldn't be unexpected.
In both testcases, the rendering of the overlapped dotted borders can be persuaded to be, hm, not a simple line of perfectly round dots, by messing with the zoom level.  Visually, you can get solid lines, dotted lines, dashed lines, odd zigzag thingies, and some others.

I agree this is not necessarily a bug, but will see if I can't make it go away as a side effect of addressing bug 379303 / bug 19963.
User Agent 	Mozilla/5.0 (X11; Linux x86_64; rv:48.0) Gecko/20100101 Firefox/48.0
Build ID 	20160414030247

This still reproduces on latest Nightly (48.0a1) with the testcase from comment 6. As this being an old bug we should choose if we consider it valid (and should be fixed) or if it can be closed as Invalid. 
As a note, it works as expected on Chrome.
Severity: normal → S3
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