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Font embedding problem: coded font names?

I've received a TeXShop-generated PDF file from a colleague in which 
many of the math symbols in the equations don't print or have obviously 
incorrect substitutions when I try to print it using Acrobat.  I also 
get Acrobat warnings like 

   "Unable to find font ABCXYZ+CMR10; Courier substituted".

Converting the PDF file to a Postscript (.ps)  file and examining this 
with a text editor shows that all of the dozen or so font names 
appearing in the file have been renamed from standard TeX names cmr10, 
cmmi10, etc., to the form "ABCXYZ+CMR10", etc, where "ABCXYZ" is a 
random string, different for each font.  I gather this is a scheme used 
to prevent font theft of copyrighted fonts in some situations, though 
I've never run into it before.  

I removed all the random strings using a text editor, so that the font 
names appeared normal; re-distilled the .ps file to PDF; and tried 
printing the re-distilled file.  (I also have a full TeXShop setup on my 
HD, so I have all the Computer Modern fonts present.) The error messages 
all went away -- but the printout was still defective.

Two queries:

1)  What option or pref should my colleague alter in his TeXShop setup 
to get fonts openly embedded?

2)  Mostly for my edification, what's this "ABCXYZ+CMR10" stuff all 
about?  What's it supposed to do?  How can this approach be truly secure 
in protecting fonts if it's so easy to trim out the "ABCXYZ" parts?  Is 
there some deeper coding in the .ps file that uses these prefixes in 
some more deeply coded form?
0
AES
4/16/2008 6:44:27 PM
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"AES" <siegman@stanford.edu> wrote in message
news:siegman-B73B54.11442716042008@nntp.stanford.edu...
[snip]
>the printout was still defective.

[...]

> 2)  Mostly for my edification, what's this "ABCXYZ+CMR10" stuff all
> about?  What's it supposed to do?  How can this approach be truly secure
> in protecting fonts if it's so easy to trim out the "ABCXYZ" parts?  Is
> there some deeper coding in the .ps file that uses these prefixes in
> some more deeply coded form?

The random prefix assures the PS device you're printing to it's an unique font,
and it should not try and substitute any of its own, built-in fonts. Primary
reason is because this happens to /subsetted/ fonts. A subset font is just a
series of glyphs (character drawings), in fairly random order -- usually, but
not always, the order in which they are encountered first in the output. Because
the link between encoding and original font glyphs is broken -- this new
encoding always starts at value '1' --, the PS device can't reliably susbtitute
the text with another font. A fairly new trick (Reader 7.0? 8.0?) is to encode
/glyph names/ as well, so text still can be copied out of it, but the internal
glyph order is still messed up.

Your printout *will not work* with any other font, including the "original" one,
because you cannot replace a subsetted, re-encoded font with another one in its
original encoding.

[Jw]


0
Jongware
4/16/2008 8:46:38 PM
AES <siegman@stanford.edu> wrote:

> all of the dozen or so font names 
>appearing in the file have been renamed from standard TeX names cmr10, 
>cmmi10, etc., to the form "ABCXYZ+CMR10", etc, where "ABCXYZ" is a 
>random string, different for each font.  I gather this is a scheme used 
>to prevent font theft of copyrighted fonts in some situations, though 
>I've never run into it before.  

Not exactly. This has no role in protection.

This six letter prefix followed by a plus sign is used to indicate a
font subset. A font may appear in a PDF file as a subset of the
characters in it, and this can happen multiple times; a PDF reader
needs to know that these are distinct subsets.

In a correctly formed PDF, all subset fonts must be embedded.
In correctly working PDF software, embedded fonts, if valid, will be
used for printing without an error.

So something is wrong with the PDF or the software. I've never see a
warning exactly like    "Unable to find font ABCXYZ+CMR10; Courier
substituted" except from Distiller; never when trying to print a PDF,
only when trying to make one.
----------------------------------------
Aandi Inston  
Please support usenet! Post replies and follow-ups, don't e-mail them.

0
quite
4/17/2008 7:33:14 AM
On Thu, 17 Apr 2008, Aandi Inston wrote:

> AES <siegman@stanford.edu> wrote:
>
>> all of the dozen or so font names
>> appearing in the file have been renamed from standard TeX names cmr10,
>> cmmi10, etc., to the form "ABCXYZ+CMR10", etc, where "ABCXYZ" is a
>> random string, different for each font.  I gather this is a scheme used
>> to prevent font theft of copyrighted fonts in some situations, though
>> I've never run into it before.
>
> Not exactly. This has no role in protection.

That is what I thought until yesterday -- read on.

> This six letter prefix followed by a plus sign is used to indicate a
> font subset. A font may appear in a PDF file as a subset of the
> characters in it, and this can happen multiple times; a PDF reader
> needs to know that these are distinct subsets.
>
> In a correctly formed PDF, all subset fonts must be embedded.
> In correctly working PDF software, embedded fonts, if valid, will be
> used for printing without an error.
>
> So something is wrong with the PDF or the software. I've never see a
> warning exactly like    "Unable to find font ABCXYZ+CMR10; Courier
> substituted" except from Distiller; never when trying to print a PDF,
> only when trying to make one.

I just encountered this with a pdf created by PageMaker+Distiller years 
ago by someone who no longer works in our lab.  Now we need to reprint the 
report.  As I recall the PDF files were created without fonts due to the 
licenses in effect at the time. Our printer had to purchase (much more 
costly) versions for the phototypsetter.  The original printer (no doubt
impoverished by the cost of those fonts) was taken over by another company 
who is unable to print the archived pdf file.

--
George White <aa056@chebucto.ns.ca> <gnw3@acm.org>
189 Parklea Dr., Head of St. Margarets Bay, Nova Scotia  B3Z 2G6
0
George
4/19/2008 8:10:13 PM
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