311635 - Wrong MathML display on OS/2

Status: RESOLVED WONTFIX

(Core :: MathML, defect)

Description

[Peter Weilbacher]

Even when all relevant fonts are installed and the warning message about missing
fonts does not appear any more, MathML does not display correctly on OS/2. This
was recently discussed widely in the netscape.public.mozilla.os2 newsgroup.

I will shortly attach a few examples.

Comment 1

[Peter Weilbacher]

Attachment: Example of Sect. 9.1 from http://math.ifi.unizh.ch/book/master.html

This shows one specific problem. All needed fonts are installed, but characters
between at least the <mo></mo> tags seem to be taken from the wrong font.

Comment 2

[Peter Weilbacher]

Attachment: Same page without math fonts installed

Without any of the math fonts installed (no TeX fonts, no Math*, no Symbol) the
page looks much nicer. It seems that especially the Symbol font takes
precedence over the normal (serif?) font whenever it is present, and is then
used to display most of the MathML.

Comment 3

[Peter Weilbacher]

OK, that part of the problem seems to be somewhat cross-platform, the Symbol
font seems to be problematic on Windows and Linux (bug 233114) and MacOS (bug
161137) at least. So let me morph this into a more general OS/2 MathML bug, as I
see at least two more problems:

1. This can be seen in attachment 198909 [details]: the "+" and "=" signs are displayed as
superscripts instead of on the same line. I would appreciate any hints where to
search for this (OS/2 gfx font code, or MathML code?). The same problem is
apparent on
<http://www.w3.org/Math/testsuite/testsuite/Presentation/TokenElements/mo/mo3.xml>.

2. OS/2 registers the TeX fonts with lower case font names (cmex10, cmsy10,
etc.) while it seems that Mozilla expects the font names to be upper case. What
would be the correct way to work around this problem? Should a line get added to
all.js (for OS/2 only) giving the lower case names?

Comment 4

[Mike Kaply [:mkaply]]

For question 2, you could probably add additional font mapping here:

http://lxr.mozilla.org/seamonkey/source/gfx/src/os2/nsFontMetricsOS2.cpp#916

Comment 5

[Peter Weilbacher]

Attachment: nsFontMetricsOS2 changes

Hmm, I did the changes you pointed me to but it doesn't seem to help. I still get the message that the font with capital letters are not installed.

Comment 6

[Mike Kaply [:mkaply]]

Attachment: Somewhat of a fix

I wrote some code that has device context send the CheckFontExistence call to fontmetrics. We think this is the right thing to do.

This makes the dialog only display "Symbol"

Of course as pointed out, the page looks better WITHOUT the math fonts installed.

Comment 7

[Mike Kaply [:mkaply]]

Actually, the font that causes the bad display is cmsy10 - if that font is not installed, things look OK. So we need to figure out why cmsy10 is getting used (I do NOT have Symbol installed)

Comment 8

[Gregg Young]

(In reply to comment #7)
> Actually, the font that causes the bad display is cmsy10 - if that font is not
> installed, things look OK. So we need to figure out why cmsy10 is getting used
> (I do NOT have Symbol installed)
> 

Take a look at https://bugzilla.mozilla.org/show_bug.cgi?id=161137. It appears that a similar problem occurred on the Mac. 

Comment 9

[Peter Weilbacher]

I don't think we will ever get this fixed on the 1.8 branch, so I'll mark this WONTFIX.

Since we investigated this problem in the OS/2 specific graphics/font code, MathML has been completely overhauled on trunk to work with the cross-platform graphics cairo-based code. It actually works as nicely for me on OS/2 as it does on Linux after a quick look at some test pages, so one could even say this matter has fixed itself...