Underlined links in the font "Trebuchet MS," which is used on mozillaZine, appear way too high up, almost as if intended as strike-through lines. This is likely a symptom in other TrueType fonts as well. I am using RH6 default xfree and xfs (w/truetype), but I don't believe those to be the problem since NC4.5 renders these links properly.

this may be a specific instance of a more generic bug having to do with underlining fonts. see bug 11101 for what is possibly another case of the same bug... also unsure whether this is a linux/unix/xfree/x-specific bug (does it work ok under windows, mac?...) in layout, or whether it would be better off in xptoolkit.

Changing summary for a more accurate description :) BTW, now might be a good opportunity to mention that not everybody has "verdana" on their system, which seems to be the standard font for the apprunner ui... Is there any proposed solution to either settle on a standard URW font or distribute a font with the final browser product?...

arrgh, sorry. there may be a bugzilla bug -- the browser stalled when i hit submit, and i thought the submission wasn't processed.

Actually, it looks like the underlines are too low on windoze as well. There is some funky code in there that makes up the underline offset and its not clear what it's doing...

Again, changing the summary and platforms according to kipp's last comment, and marking for platform parity and eating our own dogfood... Just curious why this has been pushed back to M15 as well?...

Pushed out because it shouldn't interfere with beta.

This is a rather serious bug on Linux: http://www.hotbot.com/ http://www.mozillazine.org/ http://www.fas.harvard.edu/~dbaron/ etc.

Can I get a copy of the offending font? My PC's at home don't have it :-( I can't reproduce the sheer uglyness of your attachments without out :-)

Trebuchet MS (as well as Verdana and a bunch of others) are all Microsoft "web core fonts" which you can find at http://www.microsoft.com/typography/fontpack/default.htm. Unfortunately, they're only compressed as mac stuffit or pc self-installers, but if you can grab the .ttf files out of them somehow (and run a truetype font server on your linux box) that should work for you just fine... The only thing that comes to mind is, perhaps the font server isn't behaving well... but I doubt that since it renders underlines in the same fonts in Nav4 just fine :)

I believe the underline is drawn by Mozilla, not the font server. I don't know if that was true in 4.x. Actually, NN 4.x has serious problems dealing with correctly served (xfsft) TT fonts (as opposed to TT fonts served by xfstt, which I believe have some metrics kludged).

[DOGFOOD] designation removed.

Is there actually a problem here on Win? I've never seen it, although kipp commented about underlines being too low. Or is this just a Linux bug?

Wow, we really need to get our story straight. Okay, here's the problem I noticed originally: The font underlining on the linux platform in the Trebuchet MS and Verdana typefaces was way too high up, almost as high as the line in strike-through text. Kipp then mentioned that underlines seemed too low on Windows, so I changed the summary to "inconsistent across different platforms" rather than specific to linux. I don't have access to a Linux box at this moment, so I can't comment. On Win32 I have noticed the underlining is a tiny bit low (which makes menu items uncomfortably wide from a UI perspective) and the same on Solaris, when it manages to build ;-) If somebody has access to a Linux box, put the MS "core web fonts" I mentioned on it, and run apprunner. If it comes out looking like the first two screenshots attached to this bug (note: NOT the third, because that's with helvetica substituted for trebuchet) then it is still broken. And M17 isn't the right milestone for this bug. If it comes out looking okay (screenshots baby!) then resolve it as fixed. Ooh yeah.

Perhaps this bug should be only for the problem of underlines being too high (Linux), and the bug for too low (less serious) should be separate?

The fix for this is painfully simple. It's one character: "-". I'm changing the milestone to M12 and I'll attach the fix. cc:ing erik, since he owns the code (I think - I didn't actually check cvs blame or anything).

BTW, the reason this wasn't much more obvious (when the code was written, I guess) was that it only affected TrueType/Postscript fonts since other fonts don't have built-in underline offset information.

I just realized - one other reason this might not have been noticed is that either xfstt or xfsft is returning the negative of what it should be. Someone who is using xfstt should check that this patch works OK. (Both people who claim to have seen it use xfsft, which comes with RH 6.0.) If the two font servers are returning negatives of each other, then you'll just need to use an absolute value (or negative thereof). (However, it also could be that xfstt doesn't return the info at all, and therefore the other code path is used...)

Kipp, did you see this bug when you got the fonts installed? (Since you have xfstt, that'll answer my question in my previous comment.)

OK... I switched my font server to xfstt, and it xfstt doesn't return underline offset information (by using the printf in the code right below my fix). That's why this bug shows up only with xfsft. This also means the fix shouldn't have any effect on xfstt. I don't have any postscript fonts with AFM's (I assume that's what you mean by "afm fonts"), so I can't check those. Pavlov, you wrote the comment about "afm fonts" - did you ever test them with underlines, or did you find out from someone else that the code was being used for afm fonts? Anyway - I think this fix should be checked in soon unless someone has PS fonts with AFM's and sees a problem... I'll attach a revised patch with the comment corrected!

If you search for XA_UNDERLINE_POSITION in http://vireo.gatech.edu/ebt-bin/nph-dweb/dynaweb/SGI_Developer/XLib_PG/@Generic__BookTextView/14689;cd=2 , it's clear that the UnderlineOffset should be returned as a positive number (and it's not an xfsft bug). (I think in Windows it should be returned as a negative number, since there's no minus sign in the Windows code). Mozilla seems to be using it as though it should be negative. (Unless the bug is really somewhere else - i.e., the font rendering code...)

To answer my previous parenthetical comment, nsTextFrame::PaintTextDecorations clearly assumes that the underline offset is negative, since it subtracts (lowers) it from the vertical position of the top of the underline. And, furthermore, it's XP code.

taking bug since kipp doesn't work here anymore

Mass-moving non-PDT+ bugs to M13

By the way, I'm not even positive this is a truetype bug at all... I get the same problem on Solaris (these systems do not have truetype, to my knowledge) with text styled through CSS as sans-serif, italic. This may be a problem with standard URW fonts then, also. If somebody applies the fix attached, I could verify it quickly and have this bug be a distant memory far before M13 rolls around... Any takers?

It's a problem with any fonts that claim to have metrics for underline offset info (which many do not). Pavlov, could this be checked in? It's one character...

looks good to me

Assigning to self, since I just checked in the fix (2000-01-11 18:24PST).

BTW, does anyone else see any problems with the underline metrics guessing code on other platforms? It's certainly fine on Unix. Kipp made some vague comments about it on windows, but I would guess that Windows is using metrics from the fonts. But marking fixed (see previous comment), since the main point of this bug is fixed, and it's not clear if there are any other bugs. (There's only a comment from Kipp that he thought the underline on Windows was too low. However, the underline metrics for the particular font involved (Trebuchet) are low, which is why they looked so bad when reversed in sign.)

Works fine in the Feb 01 build. Marking verified fixed.