211704 - fonts break as you scroll down with scrollbar buttons [--enable-freetype2]

Status: UNCONFIRMED

(Core :: Layout: Text and Fonts, defect)

Description

[frank fisher]

User-Agent:       Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.4) Gecko/20030624
Build Identifier: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.4) Gecko/20030624

I set up truetype fonts, with anti aliasing.  Now when I scroll through sites
that use them, the text breaks as it moves - some lines move 1 or 2 pixels and
look squashed or broken.  Refreshing or redrawing fixes them.



Reproducible: Always

Steps to Reproduce:
1.scroll by using the sidebar button, up or down
2.
3.




System - Suse 8.2, 
Mozilla 1.4 (upgraded from rc1,rc2), 
Theme - modern, 
Sans-serif font - Arial, 
Minimum font size - 12pt.

Comment 1

[David Baron :dbaron: (⌚️UTC-5, no longer working on Mozilla)]

"I set up truetype fonts, with anti aliasing."

How?  There are multiple ways to do so.

Comment 2

[frank fisher]

HI, I changed unix.js as follows

// TrueType
pref("font.FreeType2.enable", true);
pref("font.freetype2.shared-library", "libfreetype.so.6");
// if libfreetype was built without hinting compiled in
// it is best to leave hinting off
pref("font.FreeType2.autohinted", true);
pref("font.FreeType2.unhinted", false);
// below a certian pixel size anti-aliased fonts produce poor results
pref("font.antialias.min",        10);
pref("font.embedded_bitmaps.max", 1000000);
pref("font.scale.tt_bitmap.dark_text.min", 64);
pref("font.scale.tt_bitmap.dark_text.gain", "0.8");
// sample prefs for TrueType font dirs
pref("font.directory.truetype.1", "/usr/X11R6/lib/X11/fonts/truetype/");
//pref("font.directory.truetype.1", "/u/sam/tt_font1");
//pref("font.directory.truetype.2", "/u/sam/tt_font2");
//pref("font.directory.truetype.3", "/u/sam/tt_font3");
pref("font.FreeType2.printing", true);

Comment 3

[Robert Fleming]

related to bug 63336?

Comment 4

[P.L.Hayes]

I have encountered this problem too - soon after I'd found the workaround for my
problem with bug #217546 which amounted to setting up mozilla to use freetype
the same way as Mr. Fisher here. I first noticed the problem at
http://bbc.co.uk/films/ and I remembered what Mr. Baron said about xft in bug
#217546 so I rebuilt mozilla with --enable-xft instead. Going back to the above
URL, it seemed to have fixed the problem, so I began filling out this comment
and that's when I saw that it had not fixed it. It doesn't matter what font I
use - "fixed","monospace","BitStream Vera Sans Mono", etc. - the text in the
description and comments below, but not in the input text box I'm typing in, get
squashed and/or chopped off at the top or bottom. Increasing the font size with
ctrl-+ seems to fix it though.

Comment 5

[P.L.Hayes]

(In reply to comment #4)

For anyone else looking at this - the workaround given by Rickard Westman in bug
#63336 (comment #12) fixed this for me - but I had some trouble at first because
the preferences dialogue only allowed me 3 dpi settings; system, 72 and 96. 72
was too few and 96 didn't fix the problem - even when I realised you have to
restart Mozilla to effect the change. After a bit of messing around, I found it
best to set the browser.display.screen_resolution in about:config to the maximum
of the positive integers that divide 1440 that is less than the monitor's
horizontal dpi ( type: 'xdpyinfo | grep resolution' to find out what it is -
mine was 86 (86x84) so I set it to 80 for Mozilla).

Comment 6

[P.L.Hayes]

(In reply to comment #5)

Spoke too soon. It didn't fix it - it's just much less frequent now.

Comment 7

[P.L.Hayes]

(In reply to comment #6)

Well, I've now set the dpi to 72, which I didn't like before because it scaled
up the UI fonts too much and seemed too drastically different to the monitor
dpi. I set all the other font settings to their defaults and after trying my
hardest to reproduce the problem, I have not been able to. Maybe Mozilla doesn't
like integers divisible by 5 but whatever it was, it is now behaving perfectly.   

Comment 8

[Patrick]

I am seing this too with FireFox 1.0 (Linux/Suse9.1/KDE3.3.1).

In an attempt to put things together, I am listing here bug reports that seem
related to me. Sorry for not doing more analysis (and reading all the comments
of all bugs listed here) or for the bugspam but I really think this linking
might be useful. Please note that this bug is listed too (as I put the same in
different bugs).

bug 172162 Linux
bug 174977 All (was Solaris)
bug 199840 Linux
bug 211704 Linux
bug 215759 Linux
bug 217336 Linux
bug 217825 All (was Linux)
bug 228808 MacOS X
bug 248799 Linux

I built this list by searching for scroll and font in the comments from newest
to oldest going up to the first one of this list (feel free to search further)
and I might have missed some.

I put the OS as it seems there is a link between them: is it due to the usage of
a common deployed library, a bug in an OS' library, ...?

Comment 9

[Gervase Markham [:gerv]]

This is an automated message, with ID "auto-resolve01".

This bug has had no comments for a long time. Statistically, we have found that
bug reports that have not been confirmed by a second user after three months are
highly unlikely to be the source of a fix to the code.

While your input is very important to us, our resources are limited and so we
are asking for your help in focussing our efforts. If you can still reproduce
this problem in the latest version of the product (see below for how to obtain a
copy) or, for feature requests, if it's not present in the latest version and
you still believe we should implement it, please visit the URL of this bug
(given at the top of this mail) and add a comment to that effect, giving more
reproduction information if you have it.

If it is not a problem any longer, you need take no action. If this bug is not
changed in any way in the next two weeks, it will be automatically resolved.
Thank you for your help in this matter.

The latest beta releases can be obtained from:
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Thunderbird: http://www.mozilla.org/products/thunderbird/releases/1.5beta1.html
Seamonkey:   http://www.mozilla.org/projects/seamonkey/

Comment 10

[Dmitry Morozhnikov]

Same there. Still see broken lines when scrolling with 2.0.0.x. Buy the way, it is not related to scrolling with buttons. By scrolling with mouse wheel, text breaks finely too.