bugFree UCS Outline Fonts - Bugs: bug #28742, Extra glyphs at end of TTF, OTF...


bug #28742: Extra glyphs at end of TTF, OTF files

Submitted by:  Steve White <Stevan_White>
Submitted on:  Tue 26 Jan 2010 10:51:40 PM UTC  
Category:  compilation Severity:  4 - Important
Item Group:  None Status:  Fix posted
Privacy:  Public Assigned to:  Steve White <Stevan_White>
Open/Closed:  Closed Release:  2009-01-04

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Wed 27 Jan 2010 09:34:25 PM UTC, comment #1: 

1) TrueType standard has a recommendation that three special glyphs be present in the 'Controls' section of ASCII, at
0x0000 0x0001 0x000D

2) FontForge has an almost undocumented feature ( in source file tottf.c, AssignNotdefNull() ), whereby it searches for these glyphs, and does (something) with them, which results in (3).  If it doesn't find them, evidently, some other glyphs are copied there, with no concern for width etc.

3) It seems that TTF files with BMP Unicode encoding get these three glyphs copied to the end; OTF files only get 0x0000 copied.  What happens to non-BMP Unicode files seems more complicated: sometimes strange ranges of characters are copied to the end.

The solution for FreeMono seems to be, to provide glyphs for these three characters.

Should also make a check for this; maybe isMonoMono would be a good place.

Steve White <Stevan_White>
Project AdministratorIn charge of this item.
Tue 26 Jan 2010 10:51:40 PM UTC, original submission:  

As compared with the SFD files, the binary TTF and OTF files produced with FontForge 20080429 (now confirmed: also with 20090923 and 20090622) have extra characters appended.

Specifically, in this case the TTF file gets four characters
.notdef, .null, nonmarkingreturn, NameMe.1231
The OTF file gets only a

Sometimes these characters have strange widths, which may responsible in some cases for applications thinking FreeMono is not monospaced.

Thanks to Hin-Tak Leung for pointing out anomolies!

Steve White <Stevan_White>
Project AdministratorIn charge of this item.


(Note: upload size limit is set to 16384 kB, after insertion of the required escape characters.)

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    Follow 2 latest changes.

    Date Changed by Updated Field Previous Value => Replaced by
    2010-09-19 Stevan_White Open/ClosedOpen => Closed
    2010-01-27 Stevan_White StatusConfirmed => Fix posted

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