Issue 54182 - Poor equation sign rendering quality of symbol fonts
Summary: Poor equation sign rendering quality of symbol fonts
Status: CLOSED DUPLICATE of issue 59997
Alias: None
Product: gsl
Classification: Code
Component: code (show other issues)
Version: OOO 2.0 Beta2
Hardware: All Windows, all
: P5 (lowest) Trivial (vote)
Target Milestone: AOO PleaseHelp
Assignee: nospam
QA Contact: issues@gsl
Depends on:
Blocks: 82685 86412
  Show dependency tree
Reported: 2005-09-03 11:06 UTC by Matthias Basler
Modified: 2008-11-05 20:37 UTC (History)
4 users (show)

See Also:
Issue Type: DEFECT
Latest Confirmation in: ---
Developer Difficulty: ---

Screenshot taken at 200% Zoom in Writer (10.81 KB, image/jpeg)
2005-09-30 12:36 UTC, michael.ruess
no flags Details

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Description Matthias Basler 2005-09-03 11:06:24 UTC
Many user's have alread reported this (including me in issue 44668 and Colin in
issue 53688, both of which are closed):

At normal zoom (100%) and font size (12pt) the equation sign looks blurred and
the two bars are not of equal size (One is two pixels big and grey, the other
one 1 pixel and dark grey). Sometimes it's the other way round.

Is it possible to fix this?
Comment 1 michael.ruess 2005-09-30 12:36:46 UTC
Created attachment 30038 [details]
Screenshot taken at 200% Zoom in Writer
Comment 2 michael.ruess 2005-09-30 12:39:11 UTC
MRU->HDU: see my attached screenshot. In some zoom levels the equal sign is
rendered kinda unequal. This only happens with our symbol fonts. Please evaluate
wether this is a problem in displaying or building the fonts. Thanks!
Comment 3 Matthias Basler 2005-09-30 15:24:20 UTC
Update: Since I (and others) first reported this issue there has obviously been
a major change in formula rendering: I find that in 2.0RC1 anti-aliasing is
turned off. The result is that the equation sign is no longer "blurred", but now
it happens often at the standard settings (100% and 12pt TimesNewRoman), that
one of the two equation sign bars is not visible at all. So the "=" looks like a
(This effect is only seen when formula editing is finished, not while the
formula is in editing mode. P.S. Tested in Writer, not Math.)

I wouldn't call this an improvement... 
Comment 4 2005-12-05 11:47:55 UTC
HDU->IH: please make sure the symbols "autohinter-friendly".

HDU->TL: do you nowadays enable/disable the antialias flag in math?
Comment 5 nospam 2005-12-07 09:22:42 UTC
IH: as all involved people know we had a lot of bugs regarding to the rendering
quality of OpenSymbol in the past. Unfortunately I have no tool with which I can
implement proper hinting information into this font. I use Fontforge and with
Fontforge you can not hint a TrueType font. So the only things I could do in the
past was chaning the font outlines.

IH->HDU: what do you mean by "make the font auto hinting friendly"? How can I do

Comment 6 2005-12-07 10:54:04 UTC
Instead of autohinting-friendly I meant to say unhinted-friendly. E.g. in the
case of the symbol EQUAL both strokes are rather narrow. With "naive scaling" as
is done on WIN32 for unhinted glyphs it is possible that for some font pixel
heights the outline of one of the bars is scaled in such a way, that no middle
point of the raster is covered. This means that the bar is not drawn and the
EQUAL looks like a MINUS. If the strokes were just wide enough that the scenario
outlined above would not happen at small font pixel heights I would call the
symbol "looks ok even when unhinted". This problem should have been found when
the font was tested at different zoom sizes on WIN platforms.

The quality and design of the OpenSymbol font are certainly your
responsibilities and I like to help you with it. It not acceptable though that
an issue, that is clearly a bug and you are responsible to solve it, is
reassigned to me just "to get it out of your intray". Keep the issue, solve it
by testing the font on WIN and UNX and change the symbols that don't look right
until they look right. This is not black magic or something..., sorry for the
harsh words.
Comment 7 nospam 2005-12-07 11:42:52 UTC
IH->HDU: Sorry, I did not sent this back to you to "clean up my intray". I just
wanted to know what you meant by making the font more "auto-hinting-friendly".
You say that the outlines of the two bars of the "equal" symbol are very small,
but I have changed this already many times in the past because of other bugs.
Could it be that some of my fixes are not in the actual font version? I think I
have to investigate on this here. I know that I am responsible for this font and
I did not want to just simply get this away form my bug list. But I am very
disappointed about the situation that I have no appropriate tool to edit the
font in the way I want it to do. All the font edit software I have access to
here is making something strange or wrong if I touch the font with them and then
I run into problems with the QA because the fonts makes problems on some
platforms and so on. I will try to do my best to fix it and keep this bug on my
side - of course. But sometimes it is a little bit black magic, isn't it ;-) ?
Comment 8 Matthias Basler 2005-12-12 18:52:18 UTC
I wrote: "I find that in 2.0RC1 anti-aliasing is turned off. The result is that
the equation sign is no longer 'blurred', ..."

Please see my latest comment in issue 44668.
Anti-aliasing was disabled in Windows. (I didn't know there was such setting.
Now I know.)  This explains why I found anti-aliasing for the formulae to be
off. So ignore my latest comment in this issue.
Comment 9 nospam 2006-04-10 09:45:28 UTC
will be fixed in i59997

*** This issue has been marked as a duplicate of 59997 ***
Comment 10 Mechtilde 2008-11-05 20:37:12 UTC
close the duplicate