Skencil User's Guide: Configuration

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# Configuration

## Fonts

Fonts are a somewhat complex matter in Linux and X. Skencil's main output format for printing is PostScript. Because of that, Skencil identifies fonts with their PostScript names and must know how to get the appropriate metrics (these tell Skencil how to place the individual letters for instance) and it must know X's name for the font (to be able to show the text on the screen appropriately).

The information Skencil needs to map the PostScript names to metric-filenames (.afm-files) and X font names is stored in .sfd-files.

### sfd-Files

An sfd-file maps font names to the filenames of the `afm`-files and to various font attributes like weight and width and to two strings that are used to build the font name for X.

For example, the line concerning the Courier font in `Resources/Fontmetrics/std.sfd` is:

    Courier,Courier,Roman,-adobe-Courier-medium-r-normal,iso8859-1,pcrr

This tells Skencil that the metrics file is `pcrr.afm` and that the first part of the X font name is `-adobe-Courier-medium-r-normal` and its last part is `iso8859-1`. The parts missing from the X font name describe the size and transformation which are automatically filled in by Skencil. Skencil assumes that fonts can be arbitrarily scaled and transformed. (The XFree servers often used on Linux have this capability; other servers on other platforms may not)

If the font is not installed in the server (either the X-server or the font server), or if it is installed under a different name, Skencil will not be able to display the text.

On start-up, Skencil reads all sfd-files it finds in the directories listed in its font-path.

### The font-path

Skencil maintains a list of directories where it searches for font-related files like sfd-files and metrics. Note that this is a skencil-specific font-path and has nothing to do with X's font-path.

By default (as of version 0.6.2) the font-path consists of the directories `Resources/Fontmetrics` (relative to where Skencil is installed), `/usr/X11R6/lib/X11/fonts/Type1` and `/usr/share/ghostscript/fonts`.

If you need to add directories or otherwise modify the font-path, you can do so in Skencil's start-up file, `~/.sketch/userhooks.py`, which is executed by Skencil if it exists. E.g. to add a directory to the font-path you could put this code into `userhooks.py`:

    from Sketch import config

    config.font_path.append('/usr/local/share/fonts/bitstream')

In case you're wondering, Skencil was originally called `Sketch', hence the name of the directory and the python module in the above code snippet.

### Adding Fonts

If you install new Type 1 fonts on your system for use with Skencil, you have to make them available to X and you have to create an sfd-file for Skencil.

The X-specific part of this is described in the usual man-pages, like `mkfontdir(1)` (for the format of `fonts.scale` and `fonts.alias`), `xset(1)` (for ways to change the fontpath at runtime), `Xserver(1)` (for general information about the X server, including fonts) and `XF86Config(5)` (for the default configuration of XFree86).

To help with the installation, Skencil comes with a script, mkfontdb.py, that can create both Skencil's sfd-files and X's fonts.scale files. In my opinion it's a good idea to generate both files with mkfontdb.py to make sure the X-font-names in both files match, because Skencil won't be able to display the fonts otherwise.

The easiest way to use mkfontdb.py is:

    mkfontdb.py <dir>

When invoked like this, mkfontdb.py reads the afm-files in the directory <dir> and creates the two files `fonts.scale` and `std.sfd` in the current directory. For more information about the command line options run 'mkfontdb.py -h'.

A good way to install new Type 1 fonts on a Linux-system, in my opinion, is to put the files (pfb/pfa and afm) into a separate directory, e.g. `/usr/local/share/fonts` and create `fonts.scale` and an sfd file in that directory, and append it to X's font-path and Skencil's font-path.

### Installing Ghostscript's Type1 fonts for X.

To use the standard PostScript fonts, I recommend installing the appropriate Type1 fonts from the Ghostscript distribution. They are high quality fonts and distributed under the GPL.

The following suggestions and instructions are mainly for XFree86. I don't know in how far these are applicable to other X-servers or other platforms than Linux.

WARNING: The following instructions describe how to change the configuration files of XFree86. Be careful and make backup copies of the files you modify so you can restore them if something goes wrong.

Copy or symlink the necessary files from Ghostscript's `fonts` directory to `/usr/X11R6/lib/X11/fonts/Type1/` (or wherever you have X). On my system this can be done from the `Type1` directory with:

    $ ln -s /usr/share/ghostscript/fonts/*l.pfb .

Append the file `Doc/fonts.scale` to `Type1/fonts.scale`. The first line in the latter file contains a single number. This is the number of fonts listed in that file. Update that number to reflect the changes (if there are no blank lines or comments, this number is the number of lines minus 1)

You may have noticed that the font names used in `Doc/fonts.scale` don't match the ones in in `std.sfd`. The reason for this is that fonts you have just installed aren't the original adobe PostScript fonts. Instead, they were contributed to ghostscript by a company called URW. To use the standard PostScript names to refer to these fonts, append `Doc/fonts.alias` to `/usr/X11/lib/X11/fonts/misc/fonts.alias`. There is no number to update here.

The file `Doc/fonts.scale` lists Ghostscript's fonts with their own name and not with the name of the Adobe fonts they can replace. The file `Doc/fonts.alias` maps the adobe names to these real names.

Now you have to run mkfontdir(1) to update the font database:

    $ mkfontdir

If your X-server is running already you have to tell it to reread the font databases with xset(1):

    $ xset fp rehash

Concepts | Skencil User's Guide | User Scripting