[Bug 461617] New: modified Sazanami-Gothic font showing vertical text rendering glitches not seen in the original

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Summary: modified Sazanami-Gothic font showing vertical text rendering glitches not seen in the original

https://bugzilla.redhat.com/show_bug.cgi?id=461617

Summary: modified Sazanami-Gothic font showing vertical text
                    rendering glitches not seen in the original
           Product: Fedora
           Version: rawhide
          Platform: All
        OS/Version: Linux
            Status: NEW
          Severity: medium
          Priority: medium
         Component: sazanami-fonts
        AssignedTo: [e-mail]
        ReportedBy: [e-mail]
         QAContact: [e-mail]
                CC: [e-mail]
   Estimated Hours: 0.0
    Classification: Fedora

Created an attachment (id=316191)
 --> (https://bugzilla.redhat.com/attachment.cgi?id=316191)
Sample openoffice.org document with vertical text in this font

Description of problem:
OpenOffice.org documents using vertical text in Sazanami-Gothic show broken
glyphs. The spec for this font says

"
# original is
http://prdownloads.sourceforge.jp/efont/10087/sazanami-20040629.tar.bz2
# due to Bug#196433, ttf has been modified and the tarball repacked
Source0:       sazanami-%{fontver}.tar.bz2
"

if I locally revert to the original .tar.bz2 from
http://iij.dl.sourceforge.jp/efont/10087/sazanami-20040629.tar.bz2 then the
rendering look right.

See: http://qa.openoffice.org/issues/show_bug.cgi?id=92671 for discussion about
this, and the suggestion that the hacky editing of the font has gone awry.

Attached is a sample document for use with Sazanami-Gothic installed, and
screen shots of it with the modified fedora version, and a screen shot with the
tarball reverted to the original upstream one

[Bug 461617] modified Sazanami-Gothic font showing vertical text rendering glitches not seen in the original

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https://bugzilla.redhat.com/show_bug.cgi?id=461617

--- Comment #1 from Caolan McNamara   2008-09-09 10:29:45 EDT ---
Created an attachment (id=316192)
 --> (https://bugzilla.redhat.com/attachment.cgi?id=316192)
screenshot with what we have in rawhide

[Bug 461617] modified Sazanami-Gothic font showing vertical text rendering glitches not seen in the original

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https://bugzilla.redhat.com/show_bug.cgi?id=461617

--- Comment #2 from Caolan McNamara   2008-09-09 10:30:31 EDT ---
Created an attachment (id=316193)
 --> (https://bugzilla.redhat.com/attachment.cgi?id=316193)
what I get if I revert to the original upstream font tarball

[Bug 461617] modified Sazanami-Gothic font showing vertical text rendering glitches not seen in the original

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https://bugzilla.redhat.com/show_bug.cgi?id=461617

Caolan McNamara  changed:

What    |Removed                     |Added
----------------------------------------------------------------------------
    External Bug ID|                            |OpenOffice.org 92671

[Bug 461617] modified Sazanami-Gothic font showing vertical text rendering glitches not seen in the original

[Red Hat Bugzilla]

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Akira TAGOH  changed:

What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |ASSIGNED

--- Comment #3 from Akira TAGOH   2008-09-20 21:22:17 EDT ---
Thanks for reporting. BTW is Sazanami fonts still default in OOo for Japanese?
if yes, that would be better changing the default font to VL Gothic.

[Bug 461617] modified Sazanami-Gothic font showing vertical text rendering glitches not seen in the original

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https://bugzilla.redhat.com/show_bug.cgi?id=461617

--- Comment #4 from Akira TAGOH   2008-10-19 06:34:06 EDT ---
fontforge reports too much errors/warnings with exporting ttf. probably
Sazanami fonts has underlying problems.

[Bug 461617] modified Sazanami-Gothic font showing vertical text rendering glitches not seen in the original

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Bug Zapper  changed:

What    |Removed                     |Added
----------------------------------------------------------------------------
            Version|rawhide                     |10

Caolan McNamara  changed:

What    |Removed                     |Added
----------------------------------------------------------------------------
             Blocks|                            |473303(F12Blocker)

--- Comment #5 from Bug Zapper   2008-11-25 22:00:10 EDT ---

This bug appears to have been reported against 'rawhide' during the Fedora 10
development cycle.
Changing version to '10'.

More information and reason for this action is here:
http://fedoraproject.org/wiki/BugZappers/HouseKeeping

[Bug 461617] modified Sazanami-Gothic font showing vertical text rendering glitches not seen in the original

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--- Comment #6 from Nicolas Mailhot   2009-09-23 11:50:40 EDT ---
It would also be worth testing with the dev version of OO.o, since it is
supposed to correct many OO.o OpenType problems

[Bug 461617] modified Sazanami-Gothic font showing vertical text rendering glitches not seen in the original

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--- Comment #7 from Caolan McNamara   2009-09-24 04:04:05 EDT ---
This issue is unaffected by the additional opentype support and other OOo-dev
changes.

[Bug 461617] modified Sazanami-Gothic font showing vertical text rendering glitches not seen in the original

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--- Comment #8 from Akira TAGOH   2009-09-24 07:25:26 EDT ---
just tried the latest fontforge in rawhide to re-export ttf without any
updates. I can still see this issue. I'm not really sure what exactly causes
this but apparently fontforge has a problem with the default options in
exporting ttf.

[Bug 461617] modified Sazanami-Gothic font showing vertical text rendering glitches not seen in the original

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--- Comment #9 from Caolan McNamara   2009-09-24 10:45:44 EDT ---
hmm, I also see this using the fonttools ttx, i.e.
ttx -i -a -e original-sazanami-gothic.ttf
ttx -b original-sazanami-gothic.ttf
also generates output which exhibits the behaviour that the original doesn't.

[Bug 461617] modified Sazanami-Gothic font showing vertical text rendering glitches not seen in the original

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--- Comment #10 from Nicolas Mailhot   2009-09-24 16:37:45 EDT ---
It would probably be a good idea to notify ttx and fontforge authors about this
problem, maybe they can teach their tools to work around such buggy font files?

[Bug 461617] modified Sazanami-Gothic font showing vertical text rendering glitches not seen in the original

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--- Comment #11 from Akira TAGOH   2009-09-28 08:02:30 EDT ---
Created an attachment (id=362881)
 --> (https://bugzilla.redhat.com/attachment.cgi?id=362881)
Screenshot on ghostscript

I still need to investigate further more and this may mislead to get the right
thing perhaps but just tried the vertical writing on ghostscript-8.70-1.fc12.
and it looks good to me.

Coming questions would be:
1. How OOo render for the vertical writing. e.g. referring the vert table in
TTF or anything else
2. How about gs?

just for updates.

[Bug 461617] modified Sazanami-Gothic font showing vertical text rendering glitches not seen in the original

[Red Hat Bugzilla]

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comments should be made in the comments box of this bug.

https://bugzilla.redhat.com/show_bug.cgi?id=461617

--- Comment #12 from Akira TAGOH   2009-09-28 08:04:12 EDT ---
Created an attachment (id=362883)
 --> (https://bugzilla.redhat.com/attachment.cgi?id=362883)
testcase that I tried on ghostscript

[Bug 461617] modified Sazanami-Gothic font showing vertical text rendering glitches not seen in the original

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comments should be made in the comments box of this bug.

https://bugzilla.redhat.com/show_bug.cgi?id=461617

--- Comment #13 from Caolan McNamara   2009-09-29 11:45:41 EDT ---
So, on the ttx front I have some findings anyway...
upstream .ttf
$ ttx -l sazanami-gothic.ttf |grep GDEF
    tag     checksum   length   offset
    GDEF  0x00293516       30  3654796
$ od -Ax -j 3654796 -t x1 sazanami-gothic.ttf -N 30
37c48c 00 01 00 00 00 0c 00 00 00 16 00 00 00 02 00 01
37c49c 00 03 35 0f 00 01 00 04 00 00 00 02 00 00
37c4aa

unpacked and repacked with ttx as above and we get...
$ ttx -l sazanami-gothic.ttf |grep GDEF
    tag     checksum   length   offset
    GDEF  0x00293515       30  7701068
[root@Nom tmp]# od -Ax -j 3804688 -t x1 sazanami-gothic.ttf -N 30
75824c 00 01 00 00 00 0c 00 00 00 16 00 00 00 02 00 01
75825c 00 03 35 0f 00 01 00 04 00 00 00 01 00 00
75826a
which also gives the weirdness

If I now tweak the "CoverageFormat" bit (where the two above differ) for the
GDEF from Format 1 to Format 2 within ttx then it works fine. e.g.

original .ttf unpacked and repacked with my custom ttx
ttx -l sazanami-gothic.ttf |grep GDEF
    GDEF  0x00293516       30  7701068
od -Ax -j 7701068 -t x1 sazanami-gothic.ttf -N 30
75824c 00 01 00 00 00 0c 00 00 00 16 00 00 00 02 00 01
75825c 00 03 35 0f 00 01 00 04 00 00 00 02 00 00
75826a

So there is likely at least one route to solving this by e.g. extending ttx to
support an additional flag like the existing -b which says not to recalculate
bounding boxes with another one that says not to recalculate which
CoverageFormat is more efficient and turn the changes of bug 196433 into a
patch to the .ttx output of ttx. I'll have a poke at this to see if that would
work in theory at least.

[Bug 461617] modified Sazanami-Gothic font showing vertical text rendering glitches not seen in the original

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--- Comment #14 from Akira TAGOH   2009-09-29 22:23:02 EDT ---
Thanks for analysing. here is more details in TTF spec:

GDEF Header
0000: 00 01 00 00 : Version of GDEF table
0004: 00 0c       : offset to GlyphClassDef table
0006: 00 00       : offset to AttachList table
0008: 00 16       : offset to LigCaretList table
000A: 00 00       : offset to Mark Attachment Class Definition table

GlyphClassDef table
000C: 00 02       : ClassFormat
000E: 00 01       : ClassRangeCount
                  : ClassRangeRecord[0]
0010: 00 03       : Start
0012: 35 0f       : End
0014: 00 01       : Class, 1 = base glyphs

LigCaretList table
0016: 00 04       : offset to Coverage table
0018: 00 00       : LigGlyphCount

Coverage table
001A: 00 02       : CoverageFormat
001C: 00 00       : GlyphCount

In either case, there are actually no glyph definitions in the coverage table.
I'm really wondering why it affects to this.
Is it freetype or HarfBuzz bug?

[Bug 461617] modified Sazanami-Gothic font showing vertical text rendering glitches not seen in the original

[Red Hat Bugzilla]

Please do not reply directly to this email. All additional
comments should be made in the comments box of this bug.

https://bugzilla.redhat.com/show_bug.cgi?id=461617

Caolan McNamara  changed:

What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |[e-mail]
          Component|sazanami-fonts              |openoffice.org
            Version|10                          |rawhide
         AssignedTo|[e-mail]            |[e-mail]

--- Comment #15 from Caolan McNamara   2009-09-30 07:46:47 EDT ---
I'm now back to very suspicious about OOo itself. Both fontforge and ttx are
preferring the type 2 coverage format when saving this font as its more compact
in this case that the original fonts type 1 coverage table. Presuming that both
ttx and fontforge are re-encoding as type 2 correctly then it would be OOo
that's handling them incorrectly.

http://www.microsoft.com/typography/otspec/CHAPTER2.htm has "Coverage Index
(GlyphID) = StartCoverageIndex + GlyphID - Start GlyphID" which *plausibly* is
somewhere we're going wrong.

[Bug 461617] modified Sazanami-Gothic font showing vertical text rendering glitches not seen in the original

[Red Hat Bugzilla]

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comments should be made in the comments box of this bug.

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Caolan McNamara  changed:

What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |MODIFIED

--- Comment #16 from Caolan McNamara   2009-09-30 10:04:59 EDT ---
I think I have this as a bug in OOo after all :-)

It'd probably be a good idea if we were to use ttx to build our modified font
so that we could take the original source and made the modifications during our
build process to make it transparent what the changes are being made. I might
play around with that as a separate thing.

[Bug 461617] modified Sazanami-Gothic font showing vertical text rendering glitches not seen in the original

[Red Hat Bugzilla]

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Caolan McNamara  changed:

What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|MODIFIED                    |CLOSED
         Resolution|                            |RAWHIDE

--- Comment #17 from Caolan McNamara   2009-10-02 05:58:20 EDT ---
available in F-12 as 3.1.1-19.10