Department of Engineering

IT Services

PDF (Acrobat)

Acrobat is the name for a family of document interchange products written by Adobe Systems, Inc. The underlying file format is the Portable Document Format (PDF), which is based on Postscript. Any document you would normally print, can instead be turned into PDF, which represents the exact appearance of the printed document. The PDF file can then be viewed online by anyone with a free PDF Reader.

PDF is designed so that users rarely have to worry about fonts: `Standard' fonts (Adobe Times, Helvetica, Courier, Symbol and Zapf Dingbats) are available with every Acrobat installation. For other fonts, when the PDF file is produced, a description of character widths, weight and style is included. When the file is viewed, if the original font is not available, a substitute is made up from the information in the file. In most cases this is good enough; lines are the right length, characters don't crash into each other and the overall appearance is similar to the original. However, if it is essential to the author that every reader should see the correct font, the whole font (or a subset) may be embedded in the PDF file at generation time.

Since PDF is platform-independent, and reading and writing software is available for a variety of platforms (Windows, Macintosh, various flavours of UNIX), documents can be exchanged freely between users of those platforms.

On CUED's Unix Teaching System we have the following PDF-related software

  • Viewing
    • acroread is installed to view PDF files. Doing a "print to file" produces a postscript file.
    • xpdf displays PDF files.
    • gv displays PDF files (and postscript files).
    • evince
  • Checking and Manipulating
    • PDFExtracttext, PDFInfo, PDFSplit, PDFImpose, PDFMerge, PDFValidate, PDFRepair and PDFCompress are installed for PDF file manipulation and pre-flight checking. E.g. 
          PDFImpose -nup 4 foo.pdf
      creates a file with 4 old pages on each new page. See the online man pages for details, or look at the Multivalent documentation
  • Producing
    • ps2pdf and the newer ps2pdf14 convert Postscript files to PDF files.
    • xfig is a graphics editor that can export PDF files
    • OpenOffice is a word processor and graphics editor that can produce PDF output.
    • If you use LaTeX and you want to produce PDF files, consider using the hyperref package and/or pdflatex. See Producing HTML and PDF files with LaTeX for details.
    • To produce PDF files from Word under Windows you may need Adobe's Distiller. CUED staff can use a copy on the Computer Operators' PC. Note that with Acrobat 5, Adobe decided to use Times New Roman, Arial, and Courier New in place of Times, Helvetica, and Courier. If you have versions of Times, etc, that you'd like to use, use Distiller's Font Locations to show it where they are.
  • Printing - To print out PDF files, use acroread or lp from the command line.

FDF

FDF (Forms Data Format) is used for Acrobat Forms and is based on PDF. FDF files can be viewed with most PDF viewers.

Security

Some PDF files are "protected" by DRM (Digital Rights Management) controls. Sometimes these have been added to the file accidentally by the author, but there may be good reasons for limiting the viewing, copying, or printing of the file. If in doubt, contact the author!

References

Online resources from elsewhere include