94851 - Sometimes text in input boxes and text on webpages get "cut off" or wrongly look "italic".

Status: VERIFIED DUPLICATE of bug 80530

(Core :: Layout, defect, P3)

Description

[André Dahlqvist]

[CVS build from 2001-08-11-05 but I've seen this for as long as I can remember]

I have seen this for so long and on two different machines that now I finally
decided to report it. Quiet often text in input boxes (such as those on
bugzilla) are partially corrupted. The text is always fixed if I highlight the
text. It also sometimes happens with the normal text on webpages.

This is far from 100% reproducable but I come across it especially often on
bugzilla. Below is a screenshot of what I mean: look at the QA Contact input
box. I think it might be related to scrolling on these pages.

Comment 1

[André Dahlqvist]

Attachment: Image with text corrupted in "QA Contact" field.

Comment 2

[André Dahlqvist]

Attachment: Screenshot of how normal text can be cut off.

Comment 3

[André Dahlqvist]

This seams to be easiest to reproduce on bugzilla, which I guess is because it
has a lot of input fields and such. I think it is reproduced by scrolling on pages.

It is not likely to be a video card problem since I have reproduced it on two
completely separate machines. It is always fixed by marking the text.

Comment 4

[anthonyd]

need a testcase, even though I think everyone has probably seent his at one time 
or another.

not a table specific bug, reassigning to core owner.

Comment 5

[André Dahlqvist]

I realize a testcase is needed, but it's hard to get since it seams to happen
rather randomly. It might actually be that I only see it on self-built mozillas,
but I'm not sure exactly what library or whatever could cause *text* to be cut
off like this. If it was images then I could suspect a image library, but here I
have no clue.

Comment 6

[Kevin McCluskey (gone)]

Taking this bug

Comment 7

[André Dahlqvist]

Attachment: Screenshot of how text quiet often can look almost "italic" although it really isn't

Below I will provide steps that makes this case reprocuable for me.

Comment 8

[André Dahlqvist]

[Self-compiled build from 2002-01-25-15 using the 0.9.8 branch]

This bug is so damn annoying that I'm going to try to track it down:-) I
actually ran into what, for me, is a reproducable case:

1) Go to http://www.3dxtreme.org/as3.shtml
2) Scroll down *slowly* on the page until you can see the title "Features of
Arctic Silver 3 (from the AS web)"
3) If the title still doesn't look like in attachment 66690 [details], scroll further down
on the page until this title reaches your Personal Toolbar, and scroll slowly
just as it is hidden under the toolbar. Then scroll back slowly so it is visible
again. Try that a few times and hopefully you should see the effect.

Result: This perticular title should look similar to attachment 66690 [details]

If it doesn't immediatly happen, please try similar steps a few times and try to
reload inbetween tries. For me it is rather easy to reproduce on this
perticular page.

It is weird that only one line on the page is affected in this way, could it be
related to the fact that this very text line has a horitontal line just above it?

It would be nice to hear if someone else can reproduce it on this page.

Comment 9

[André Dahlqvist]

Sorry, the correct URL is: http://216.194.77.210/as3p2.shtml

Comment 10

[Kevin McCluskey (gone)]

Bulk moving Moz1.2 bugs to future-P3. I will pull from this list when scheduling
post Mozilla1.0 work.

Comment 11

[André Dahlqvist]

Attachment: Yet another screenshot of this happening

I realize a screenshot isn't very helpful here, but I'm lost as to whatelse to
do. I cannot manage to find a good testcase, but yet I see this happen several
times each session.

Does anyone else see this happening? I'm on Debian GNU/Linux 3.0.

Comment 12

[André Dahlqvist]

Kevin, what, if anything, can I do you help you nail this bug? I simply cannot
find a reliable way to always reproduce this, but it still happens for me all
the time. This is by far my most hated Mozilla bug ever.

It happens regardless if I use a font server or not. It happens regardless if I
use truetype fonts or not. It also doesn't matter if I set the minimum font
preference or not. http://www.gnuheter.com is a page that I see it on most
oftenly, but it is in no way limited to this site. The bug where the text looks
almost italic is what I'm primarily seeing: it looks as if the upper 50% of the
fonts have been shifted one pixel too much to the right or to the left.

Pointing on the text line in question, and marking a few characters with the
mouse will *always* make the text get "straightened up".

Comment 13

[André Dahlqvist]

Attachment: Screenshot of xmag that shows the font magnified and the step like effect on the fonts

Comment 14

[Kevin McCluskey (gone)]

This bug looks like a dup of 80530.
I have been working on a fix for 80530 but the problem is not simple. The off by
one pixel problem is caused by the pixel to twip conversions done in numerous
parts of the code.

*** This bug has been marked as a duplicate of 80530 ***

Comment 15

[André Dahlqvist]

Yeah, that sounds exactly like this bug. Go Kevin, go!