[texhax] labeling images with text

Ross Moore ross at maths.mq.edu.au
Fri Sep 24 02:47:51 CEST 2004

Hi Reinhard, Robin, and others

On 24/09/2004, at 7:36 AM, Reinhard Kotucha wrote:

> There are two packages which you can use.  Robin and Ian already
> mentioned them.  The difference between them is that the positioning
> of the labels is done either in the eps file (psfrag) or in the latex
> file (overpic) while the labels themselves are defined in the latex
> file in both cases.

There's a third method which is very powerful -- more so than
either of the above two, but requires more to setup; though
you get back much more for the effort.


> I recommend to read the documentation of both packages carefully
> before you decide which way to go.

The above site gives lots of examples, as well as links to TUGboat
articles where the basis of the methods are described in some detail.

>> Where can I go for help?

As a quick comparison:


    *  uses LaTeX's picture environment;
    *  you place other elements by specifying coordinates which you
       have to guess or use trial-and-error;
    *  the nice part is that coords can be given as fractions of the
       width/height of the imported image, so that the locations of
       your labels/annotations do not change if the image is scaled.


    *  relies upon clever PostScript tricks to place TeX typeset
       material at marked places within the .eps image.
    *  this requires preparing your .eps image specially with the
       labelling in mind -- not good for images from elsewhere.
    *  This method does *not* carry over to pdfTeX
       --- though you can still use it in conjunction with the
        ps4pdf  package.

    *  IMHO, while cute and powerful, this method is inherently
       unstable with respect to changes in how PostScript and PDF
       are supported by other software down the production chain.

  WaRMreader/Marked Objects

    *  uses extra (intuitive) logical markup of features contained
       within the image --- metadata for image content, so to speak.
    *  uses the Xy-pic package for graphics and diagrams in (La)TeX.
    *  by interpreting the extra metadata, the places to place labels
       can be located in a coordinate-free manner;
    *  the full power of Xy-pic is available for placing labels
       at/above/below/nearby/centered/etc. these locations.
    *  works with any image that you can use with TeX or LaTeX,
       **provided** you can construct the metadata. The .eps images
       (or other format) are **not** altered in any way.
    *  a plug-in tool for Adobe Illustrator is available to create
       the metadata --- freely available for Windows or Mac.
    *  Papers describe the (text-only) format, so that other tools
       can be used as well, to generate the metadata in a suitable way.

Xy-pic + WaRMreader is not everybody's cup of tea,
but it does give a powerful, reliable way to annotate graphics.

The metadata is stored external to the image, and can serve
as a searchable file that contains information about an images
contents, so could potentially be used for other applications.

> Don't know which system you use, but maybe you'll find somwething
> useful under .../texmf/doc/...
> If you're in luck you have a program called texdoctk installed on your
> system.

Hope this helps,

	Ross Moore

> Regards,
>   Reinhard
> --  
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> Reinhard Kotucha			              Phone: +49-511-4592165
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Ross Moore                                         ross at maths.mq.edu.au
Mathematics Department                             office: E7A-419
Macquarie University                               tel: +61 +2 9850 8955
Sydney, Australia                                  fax: +61 +2 9850 8114

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