9 Replies Latest reply: Nov 10, 2014 12:28 PM by JamieLaManger RSS

    PDF CID keyed font support

    JamieLaManger Community Member

      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

        • 1. Re: PDF CID keyed font support
          lrosenth Adobe Employee

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

          • 2. Re: PDF CID keyed font support
            JamieLaManger Community Member

            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?

            • 3. Re: PDF CID keyed font support
              lrosenth Adobe Employee

              You don’t.

              • 4. Re: PDF CID keyed font support
                JamieLaManger Community Member

                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.

                • 5. Re: PDF CID keyed font support
                  JamieLaManger Community Member

                  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.

                  • 6. Re: PDF CID keyed font support
                    lrosenth Adobe Employee

                    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.

                    • 7. Re: PDF CID keyed font support
                      JamieLaManger Community Member

                      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

                      • 8. Re: PDF CID keyed font support
                        lrosenth Adobe Employee

                        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)

                        • 9. Re: PDF CID keyed font support
                          JamieLaManger Community Member

                          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)?