Apache OpenOffice (AOO) Bugzilla – Issue 54182
Poor equation sign rendering quality of symbol fonts
Last modified: 2008-11-05 20:37:12 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?
Created attachment 30038 [details] Screenshot taken at 200% Zoom in Writer
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!
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 minus. (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...
HDU->IH: please make sure the symbols "autohinter-friendly". HDU->TL: do you nowadays enable/disable the antialias flag in math?
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 this?
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.
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 ;-) ?
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.
will be fixed in i59997 *** This issue has been marked as a duplicate of 59997 ***
close the duplicate