Adobe Community: Message List - PDF CID keyed font support

Re: PDF CID keyed font support

forums_noreply@adobe.com — Mon, 10 Nov 2014 20:28:33 GMT

thanks ever so much for the info.

One last thing - I said earlier that I thought I had examples of CIDFonts that had non CFF data, I think I may well have got that wrong.

To your knowledge, does the CIDFont spec support type 1 charstrings (like you find in type 1 fonts)?

Re: PDF CID keyed font support

forums_noreply@adobe.com — Mon, 10 Nov 2014 15:22:49 GMT

ISO Standard is the document you should be using – it supersedes all of the Adobe references.

Correct. You need to convert the T1->CFF for use in a CIDFont.

(and yes, PS also did CIDFonts of more complexity)

Re: PDF CID keyed font support

forums_noreply@adobe.com — Mon, 10 Nov 2014 14:35:02 GMT

I thought CIDFonts existed in the PS world well before PDF, and also, in the PS world, CIDFonts are more complex because they aren't limited to a single descendent font.

My understanding of the PDF spec is that a composite font has only 1 descendant unlike in PS. But that's a bit off topic.

AFP (a nasty old IBM transactional print language) will generate CIDFonts which use type1 font (not CFF) as a descendent - these CIDfonts are handled by FreeType.

the problem I have is how to embed them in PDF (when converting the AFP stream to PDF).

The bit you quote from the ISo standard is really clear, I agree, I had been using the PDF reference manual which doesn't specify CFF for composite based in type1, it says:

"•A Type 0 CIDFont contains glyph descriptions based on the Adobe Type 1 font format"

based on the ISO spec and what you tell me, I guess it is clear that you cannot represent a CIDFont which is based on a non-CFF font program in a PDF file unless you convert the Type1 font to CFF. Is that right?

Thanks

AFO

Re: PDF CID keyed font support

forums_noreply@adobe.com — Mon, 10 Nov 2014 14:22:49 GMT

ISO 32000-1:2008 (aka the PDF standard) is very clear on the topic:

9.7.4.1 General

A CIDFont program contains glyph descriptions that are accessed using a CID as the character selector. There

are two types of CIDFonts:

• A Type 0 CIDFont contains glyph descriptions based on CFF

NOTE The term “Type 0” when applied to a CIDFont has a different meaning than for a “Type 0 font”.

• A Type 2 CIDFont contains glyph descriptions based on the TrueType font format

I am confused, however what print language you are converting to PDF that has a CIDFont, since that is a PDF-centric concept.

Re: PDF CID keyed font support

forums_noreply@adobe.com — Mon, 10 Nov 2014 14:14:12 GMT

can I add a little background to my question.

We have a print language conversion application that can receive fonts from a variety of sources.

One such source will generate CIDFonts that contains type 1 font programs and these are perfectly valid, they can be rendered by the FreeType library etc.

however, if transforming a print stream to PDF, I am worried that PDF cannot represent such a thing (non CFF, CID keyed).

If I know that this is the case, then I know that we have the big problem of Type1 to CFF conversion in order to embed the font in pDF.

This is what has prompted my question.

Re: PDF CID keyed font support

forums_noreply@adobe.com — Mon, 10 Nov 2014 14:05:44 GMT

ok, let me rephrase my question a little.

please explain why the fact that a type1 font doesn't know about Unicode means that a CID keyed font has to use a CFF embedded font program rather than, for instance, a CIDFont that uses a type 1 font program.

Re: PDF CID keyed font support

forums_noreply@adobe.com — Mon, 10 Nov 2014 13:44:24 GMT

You don’t.

Re: PDF CID keyed font support

forums_noreply@adobe.com — Mon, 10 Nov 2014 13:35:57 GMT

thanks for the reply, but I don't quite understand your answer.

Could you explain to me how the Unicode issue affects and explains your assertion that only CFF is supported?

My understanding is that a composite font in PDF has to use a CMap to generate a numeric CID, the problem with a type 1 font would then be that glyphs are selected by name - how do you

map a CID to a glyph name?

Re: PDF CID keyed font support

forums_noreply@adobe.com — Mon, 10 Nov 2014 12:08:34 GMT

You can only use CFF-based Type 1 fonts for CID, since a classic Type 1 didn’t know anything about Unicode.

PDF CID keyed font support

forums_noreply@adobe.com — Mon, 10 Nov 2014 12:00:44 GMT

Hi,

I understand that PDF supports embedded CFF font programs for composite fonts of type CIDFontType0 - the spec is clear.

But, does it support embedded font programs that are not CFF - ie. CIDFont with type 1 descendent for example?

The spec only mentions CFF when talking about type 1 composite fonts, but it isn't totally clear.

So, does PDF support embedded non-CFF programs for composite type 1 fonts?

regards

Steve