|  |  | 2 About Ipe files

# 2 About Ipe files

Ipe 6.0 creates (Encapsulated) Postscript or PDF files. These files can be used in any way that PDF or Postscript files are used, such as viewed with Ghostview, with Acrobat Reader or Xpdf, edited with Acrobat, or included in Latex/Pdflatex documents. However, Ipe cannot read arbitrary Postscript or PDF files, only files it has created itself. This is because files created by Ipe contain a special hidden stream that describes the Ipe objects. (So if you edit your Ipe-generated PDF file in a different program such as Adobe Acrobat, Ipe will not be able to read the file again afterwards.)

You decide in what format to store a figure when saving it for the first time. Ipe gives you the option of saving with extensions "eps" (Encapsulated Postscript), "ps" (Postscript), "pdf" (PDF), and "xml" (XML). Note that only documents of a single page can be stored in Encapsulated Postscript format, as this format doesn't support multi-page documents. Files saved with extension "xml" are--obviously--XML files and contain no Postscript of PDF information. The precise XML format used by Ipe is documented later in this manual. XML files can be read by any XML-aware parser, and it is easy for other programs to generate XML output to be read by Ipe. You probably don't want to keep your figures in XML format, but it is excellent for communicating with other programs, and for converting figures between programs.

There are perhaps two major uses for Ipe documents. The first is for inclusion into Latex documents, the second is for making presentations. There isn't much to be said about the second use: You create a PDF file with Ipe, and either print it on transparencies or present it using a laptop with Acrobat Reader. You should read the section on page views if you plan to make on-line presentations, as Ipe allows you to create pages that are displayed incrementally in Acrobat Reader.

So let's concentrate on the first and original use of Ipe documents, inclusion in Latex documents. Most Latex installations support the inclusion of figures in Encapsulated Postscript (EPS) format (the "Encapsulated" means that there is only a single Postscript page and that it contains a bounding box of the figure).

The standard way of including EPS figures is using the `graphicx` package. If you are not familiar with it, here is a quick overview. In the preamble of your document, add the declaration:

      \usepackage{graphicx}

One useful attribute to this declaration is `draft`, which stops LaTeX from actually including the figures--instead, a rectangle with the figure filename is shown:

      \usepackage[draft]{graphicx}

To include the figure "figure1.eps", you use the command:

      \includegraphics{figs/figure1}

Note that it is common not to specify the file extension ".eps". The command `\includegraphics` has various options to scale and rotate the figure. For instance, to scale the same figure to 50%, use:

      \includegraphics[scale=0.5]{figs/figure1}

To scale such that the width of the figure becomes 5 cm:

      \includegraphics[width=5cm]{figs/figure1}

Instead, one can specify the required height with `height`.

Here is an example that scales a figure to 200% and rotates it by 45 degrees counter-clockwise. Note that the scale argument should be given before the `angle` argument.

      \includegraphics[scale=2,angle=45]{figs/figure1}

Let's stress once again that these commands are the standard commands for including EPS files in a LaTeX document. Unlike in previous versions of Ipe, Ipe files neither require nor support any special treatment.1 If you are used to other commands for EPS inclusion, such as the old-fashioned `epsfig` package,2 you can use them as well for Ipe figures. If you want to know more about the LaTeX packages for including graphics and producing colour, check the `grfguide.tex` document that is probably somewhere in your TeX installation.

If you are a user of Pdflatex (a version of Latex that produces PDF instead of DVI output), you cannot include EPS files. Instead, save your Ipe figures in PDF format, and include them in the way described above.

There is a slight complication here: Each page of a PDF document can carry several "bounding boxes", such as the MediaBox (which indicates the paper size), the CropBox (which indicates how the paper will by cut), or the ArtBox (which indicates the extent of the actual contents of the page). Ipe automatically saves, for each page, the paper size in the MediaBox, and a bounding box for the drawing in the ArtBox. Ipe also puts the bounding box in the CropBox if you have ticked the Use CropBox checkbox in the Document properties (in the Edit menu).

Now, when including a PDF figure, Pdflatex will (by default) first look at the CropBox, and, if that is not set, fall back on the MediaBox. It does not inspect the ArtBox, and so it is important that you have Use CropBox ticked when making figures for inclusion in Pdflatex. On the other hand, when making presentations or full-page documents, you will want to untick Use CropBox, as otherwise Acrobat Reader will not display full pages (Acrobat Reader actually crops each page to the CropBox).

If you have a recent version of Pdflatex (1.20 or higher), you can actually ask Pdflatex to inspect the ArtBox by saying `\pdfoptionalwaysusepdfpagebox5`. (But in Pdflatex 1.30, the primitive was renamed to `\pdfforcepagebox5`.) This will result in a warning message during the Pdflatex run, so it is probably simpler to keep using CropBoxes--you'll have less explaining to do to co-authors and publishers.

You can save all your figures in both EPS and PDF format, so that you can run both Latex and Pdflatex on your document--when including figures, Latex will look for the EPS variant, while Pdflatex will look for the PDF variant. (Here it comes in handy that you didn't specify the file extension in the `\includegraphics` command.)

It would be cumbersome to have to save an Ipe figure in both formats each time you modify it. What you should do instead, is to always save in one format--let's say EPS. You can then write a shell script or batch file that calls ipetoipe to do the conversion to PDF. Alternatively, you can enable auto-exporting from EPS to PDF in Ipe.

On the other hand, if you only use Pdflatex, you might opt to exploit a feature of Pdflatex: You can keep all the figures for a document in a single, multi-page Ipe document, with one figure per page. You can then include the figures one by one into your document by using the `page` argument of `\includegraphics`.

For example, to include page 3 from the PDF file "figures.pdf" containing several figures, you could use

      \includegraphics[page=3]{figs/figures}

|  |  | 2 About Ipe files