[tex-live] [XeTeX] Problem with ocrb10.otf ligature 'fi'

[Zdenek Wagner]

2011/6/13 Pander <pander at users.sourceforge.net>:
> TeX Live list members: see full thread here:
> http://tug.org/pipermail/xetex/2011-June/020681.html for now keep the
> discussion at XeTeX's list.
>
> On 2011-06-13 14:22, mskala at ansuz.sooke.bc.ca wrote:
>> On Mon, 13 Jun 2011, Pander wrote:
>>> TeX Live 2010
>>>
>>> /usr/local/texlive/2010/texmf-dist/fonts/opentype/public/ocr-b-outline/ocrb10.otf
>>
>> That is Zdeněk Wagner's auto-conversion of Norbert Schwarz's Metafont
>> source.  It doesn't contain f-ligatures no matter what the GSUB table may
>> say.  I took a look at it with Fontforge and I see that it contains a GSUB
>> table pointing the ligatures at "alternate" and added non-ASCII characters
>> from the Schwarz version, some of which happen to be ligature-like but not
>> the correct ones.  For instance, "fl" points at the Æ glyph.
>>
>> I recogize that pattern because it happened in an earlier version of my
>> own version of the font, as a result of auto-conversion.  The thing is,
>> Schwarz's Metafont files used a nonstandard custom encoding.  If you
>> simply convert the font code point for code point to whatever the default
>> 8-bit Adobe encoding might be, you end up with Schwarz's extra glyphs at
>> the "f-ligature" code points (as well as some distortions at quotation
>> mark, dotless i and j, and similar code points).  The existence of a GSUB
>> table pointing at those points can probably be explained by defaults from
>> the auto-conversion.  So in summary, yes, it's a bug in the font.
>
> Could the conversion software generate a warning when it recognises such
> a situation?
>
The fonts were first converted to PFB by mftrace, then opened in
FontForge and saved as OTF. No warning was displayed.

>> The current version of my own OCR B fonts, available on ansuz.sooke.bc.ca,
>
> http://ansuz.sooke.bc.ca/page/fonts
>
>> is also based on Schwarz's, but via a more manual conversion process
>> (rewriting the Metafont sources to work with MetaType1), and I've
>> attempted to put all glyphs at their correct Unicode code points.  It
>> contains a GSUB table for alternate forms of glyphs, but none for
>> ligatures.
>>
>>>> I just downloaded the demo from here:
>>>>       http://www.barcodesoft.com/ocr_font.aspx
>>
>>> Maybe TeX Live should use these OTF files?
>>
>> Barcodesoft's "free" version is a watermarked demo of an expensive
>> commercial product, basically just an advertisement, and for that reason I
>> wouldn't recommend its distribution in TeXLive; I'm not even sure that the
>> license agreement would allow such distribution.
>
> In effect it is freeware and is owned by Barcodesoft. But according to
> your README, one is allowed to redistribute this and your enhanced
> version. So in the same way would TeX Live be able to so. The metadata
> in the font files provides proper credits.
>
> I think, first CTAN needs to be properly updated, see:
>  http://ctan.org/search/?search=ocr&search_type=description
> Probably many of these CTAN package can merge.
>
> Subsequently TeX Live can do their update. For now, I'll forward this
> also to them.
>
> Would it also be possible to generate Bold, Italic, Light and Condensed
> versions for OCR-A and OCR-B? In that way it is also backwards
> compatible with the current OCRA fonts.
>
If someone uploads better version of OCR-A and OCR-B fonts to CTAN, I
won't mind if my fonts are deleted. I needed OCR-B for EAN13 only and
have not tested them in other situations.


-- 
Zdeněk Wagner
http://hroch486.icpf.cas.cz/wagner/
http://icebearsoft.euweb.cz