Issue 107831 - Deprecated SEAC operator is not supported in PS-OTF
Summary: Deprecated SEAC operator is not supported in PS-OTF
Alias: None
Product: gsl
Classification: Code
Component: code (show other issues)
Version: OOO320m8
Hardware: All All
: P4 Trivial (vote)
Target Milestone: AOO PleaseHelp
Assignee: AOO issues mailing list
QA Contact:
Depends on: 43029
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Reported: 2009-12-22 11:24 UTC by
Modified: 2017-05-20 11:33 UTC (History)
3 users (show)

See Also:
Latest Confirmation in: ---
Developer Difficulty: ---

patch for fontforge/fontlint to warn about depreciated SEAC-like operator in Type2 (694 bytes, patch)
2009-12-28 10:11 UTC,
no flags Details | Diff

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Description 2009-12-22 11:24:20 UTC
The Type1 SEAC-Operator ("Standard Encoding Accented Character") is very limited and 
compared to subrs it only has drawbacks. So it always was deprecated for CFF and 
PS-OpenType fonts. Still there are some fonts that were converted 1:1 from their Type1 
counterparts which didn't decompose the SEAC operator into two subr calls. These fonts 
should get properly converted.

If there are still some important fonts which use SEAC for their accented glyphs in the 
StandardEncoding then adding support for this obsolete feature should be considered.
Comment 1 2009-12-22 11:27:36 UTC
Also see :
"Developers asked about the need for decomposing SEAC glyphs. SEAC is an old and very 
limited composite glyph mechanism from the Type 1 format. It only works if both the accent 
and the base character are in Adobe StandardEncoding. SEAC has been deprecated in CFF 
and OpenType, and is not well supported in all enivronments today. If using FontLab, go to the 
preferences for "Generating OpenType PS (.otf)" and make sure the option to "Decompose all 
composites" is on."
Comment 2 nmailhot 2009-12-22 13:07:00 UTC
Is this something fontlint warns about?
If not could you contribute a test to fontlint so font distributors can test for
this pattern?
Comment 3 2009-12-22 13:59:17 UTC
I'm not sure whether fontlint already warns about this yet, but the related fontforge project is already 
aware of the problem as the quick grep over the source shows
    fontforge/splinesave.c:/* Type2 doesn't allow any seacs */
What is meant here are the Type2 charstrings and these are used in about every PS-OTF-font out there to 
define the glyph outlines.

If fontlint doesn't warn about it yet doing so would be a good idea.
Comment 4 2009-12-22 15:15:58 UTC
Also see :
  "In the CFF/Type 2 charstring format, the seac operator is not supported."

The priority of this issue depends on the importance of the fonts that have this problem. I do not expect 
them to be plentyful since if they were important enough to be maintained they would not use illegal 
operators. Anyway, here is the start of the list:
- "Yanone Kaffeesatz"
- older versions of "FreeFontPro"
Comment 5 2009-12-22 15:33:49 UTC
Correction: current versions of "Yanone Kaffeesatz" use only non-deprecated operators. Thanks Jan!
Comment 6 2009-12-22 15:36:24 UTC
- ZapfinoPro is affected (
Comment 7 2009-12-28 10:11:48 UTC
Created attachment 66865 [details]
patch for fontforge/fontlint to warn about depreciated SEAC-like operator in Type2
Comment 8 e7 2010-02-24 21:07:05 UTC
Additional Font: FrutigerNextLT (some chars: ä ö „ “).
Comment 9 2010-03-10 10:47:16 UTC
Upstream fontlint now has applied the suggested patch (and some other nice checks):
Thanks Kevin for suggesting it. AFAIK no fonts provided by the distributions were affected. The change 
will hopefully prevent them from ever getting new fonts with the old problem.
Comment 10 Marcus 2017-05-20 11:33:22 UTC
Reset assigne to the default "".