121920 - fonts drawn improperly (cut off) when page is scrolled

Status: RESOLVED DUPLICATE of bug 80530

(Core :: Layout, defect, P3)

Description

[Danek Duvall]

This is with a 2002-01-24 build, but has been happening for a few weeks at
least.  It happens quite easily on Solaris, but I've also seen it on Linux.

To reproduce it, go to the URL above, position the scroll bar so that the last
line of text visible is partly cut off.  Then scroll down.  You'll see that each
line that gets scrolled into view has a horizontal line of pixels missing,
corresponding to where the bottom of the visible page was.  Anything that forces
a redraw (highlighting the text, covering and uncovering the window) restores it.

This doesn't happen on all web pages, but I've managed to distill a test page
which illustrates the problem.  Though even this sample isn't representative of
all the examples I've seen in the wild.

Comment 1

[Danek Duvall]

Attachment: Test page which has the problem

This page shows the problem.  The key here seems to be that there is an <h1>
heading, preceded by normal text.  This text can also be as simple as a <p>
tag.  If that text is removed or if the <h1> tag is changed to <h2>, the
problem disappears.

Comment 2

[Danek Duvall]

Attachment: An image illustrating the problem

Here's a picture of the problem.  The font is 14pt adobe-times-iso8859-1, from
Solaris 8.

Comment 3

[rubydoo123]

This same behavior can be repeated in 4.x, if you scroll to mid-line via the 
slider and then select to scroll via the scrollbar arrow, you end up on 
mid-lines. This is easily adjusted by setting the scroll line from the slider 
and then scrolling via the arrow.

Comment 4

[Danek Duvall]

I do not see it in 4.77 (at least, not when looking at the same pages where it
shows up in Mozilla).  And it's only shown up for me in the past month in Mozilla.

I honestly think that the Severity is worse than minor because it's making a
good portion of the web pages I read difficult to read.  If it showed up only
occasionally, I wouldn't be bothered quite so much, but it's really a PITA to
read some stuff now, and it hasn't always been this way.

Comment 5

[Danek Duvall]

Here's another URL which demonstrates the problem all by itself; you don't even
have to scroll!  I guess it's the scrolling induced by the graphics getting
loaded.  This'll be my last example; there's plenty of material here if someone
who wants to fix the bug needs to reproduce it.

http://www.citi.umich.edu/projects/smartcard/smartcard_seminar/8.html

Comment 6

[Chris Petersen]

Changing to P3.

Comment 7

[Heiko Garrelts]

This seems to be a duplicate of <a
href="1http://bugzilla.mozilla.org/show_bug.cgi?id=122577">Bug #122577</a>.

Comment 8

[Andrew Hagen]

Resolving as duplicate. If this is not a duplicate, reopen.

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