Laurent Guerby guerby@acm.org writes:
PS: do you have any URL about Adobe's claims?
The following is an excerpt from the PDF specification, version 1.3, dated 1999-03-11.
AFAIK, a U.S. court ruled that if you can interface a software package in just one way which always leads to the same code, this code cannot be copyrighted, so it is a bit questionable if the Adobe approach works at all.
| 1.7 Copyright permission to use PDF | | The general idea of utilizing an interchange format for final-form | documents is in the public domain. Anyone is free to devise his or her | own set of unique commands and data structures that define an | interchange format for final-form documents. Adobe owns the copyright | in the data structures, operators, and the written specification for | the particular interchange format called the Portable Document | Format. These elements may not be copied without Adobe's permission. | | Adobe will enforce its copyright. Adobe's intention is to maintain the | integrity of the Portable Document Format as a standard. This enables | the public to distinguish between the Portable Document Format and | other interchange formats for final- form documents. | | However, Adobe desires to promote the use of the Portable Document | Format for information interchange among diverse products and | applications. Accordingly, Adobe gives copyright permission to anyone | to: | | | · Prepare files in which the file content conforms to the Portable | Document Format. | | · Write drivers and applications that produce output represented in | the Portable Document Format. | | · Write software that accepts input in the form of the Portable | Document Format and displays the results, prints the results, or | otherwise interprets a file represented in the Portable Document | Format. | | · Copy Adobe's copyrighted list of operators and data structures, | as well as the PDF sample code and PostScript language Function | definitions in the written specification, to the extent | necessary to use the Portable Document Format for the above | purposes. | | The only condition on such copyright permission is that anyone who | uses the copyrighted list of operators and data structures in this way | must include an appropriate copyright notice. | | This limited right to use the copyrighted list of operators and data | structures does not include the right to copy the Portable Document | Format Reference Manual, other copyrighted material from Adobe, or the | software in any of Adobe's products which use the Portable Document | Format, in whole or in part, nor does it include the right to use any | Adobe patents.