Eric Foster-Johnson

Listing Available Fonts

The X Window system comes with a huge set of fonts. To see a listing of the fonts available on your system, try a program called xlsfonts:

xlsfonts | more

This lists out many fonts, such as:

-adobe-courier-bold-r-normal--12-120-75-75-m-70-iso8859-1 -adobe-new century schoolbook-medium-r-normal--34-240-100-100-p-181-iso8859-1 -daewoo-gothic-medium-r-normal--16-120-100-100-c-160-ksc5601.1987-0 -misc-fixed-medium-r-normal--14-130-75-75-c-140-jisx0208.1983-0 lucidasans-bold-14 cursor

Decoding Long Font Names

Some of the multi-part names are quite long. These names follow a standard called X Logical Font Description, or XLFD.

Each part of an XLFD name is separated by a hyphen. If a part is missing, you'll see two hyphens in a row. You can also use wildcards, such as * for fields you don't care about.

Going in order, from left to right, the fields follow:

For more information on XLFD fonts, see chapter 7 in The UNIX System Administrator's Guide to X.

Window Managers

One of the main things that distinguish X from most other windowing systems, such as Windows or Macintosh, is that X separates the window manager from the windowing system. X allows you to run any window manager you want, and it is the window manager that controls the title bar and other "decorations" around your windows' client areas.

Major desktop environments, such as GNOME and KDE, come pre-built with one or more window managers that help provide a consistent desktop.

The window manager controls the initial placement of windows on your screen. It also controls the title bar. (The title bar is actually a window that the window manager creates.) The window manager is in charge of how you go about resizing and moving windows. And, some window managers provide a set of virtual screens, which allow you to organize your windows (and applications) across a number of virtual screens, each of which looks like the full screen you have.

This is all quite a lot different from Windows or Macintosh systems, where the window manager comes built-in and you don't have a lot of control over how it acts. In X, you can simply run a different window manager. Also in X, the title bar is a separate window, owned and managed by the window manager program. In the Windows and Macintosh environments, the title bar is part of your application's window and your application draws into the client area of the window. In X, all you have is the client area. The window manager controls the rest.

Controlling Window Decorations

Because the window manager is in charge of so much, you'll oftentimes want your programs to communicate with the window managers to request various features, such as the title to display in the title bar and so on. The X Window method to do this is by following the Inter-Client Communications Conventions Manual, or ICCCM. (X defines application programs as clients.)

Unfortunately, the ICCCM does not define all you'll normally want for communicating with the window manager. The problem is that the two main window managers, Motif and Open Look, each use proprietary extensions to the ICCCM to control things like whether the window title bar has resize handles and so on. Therefore, the ICCCM is no good for dealing with this. Instead, you need to program to the proprietary extensions used by both the Motif and Open Look window managers (luckily, these extensions don't overlap).

The following charts, extracted from Power Programming Motif, may help.

Window Manager Resources in Motif

If you're programming with Motif, you can use traditional Xt resources to control many aspects of the window manager, with special emphasis on the Motif window manager, mwm. If the current window manager is compatible with Motif conventions, then the following will also apply.

Open Look Window Manager

The Open Look window manager, olwm, uses a different set of X window properties than mwm for controlling its behavior. The bad part about this is that you have to set both types of properties to make your application robust in a number of different window manager environments. The good part, though, is that the Motif and Open Look properties don't conflict, so you can safely set both types for all your application's top-level windows.

Since the designers of Motif assumed you'd only run the Motif window manager, there are no nice resources for the Open Look window manager, at least not from within Motif applications. Instead, you need to set X properties on your top-level windows.

To control olwm title bar decorations, the first step is to set the _OL_WIN_ATTR property, which contains five 32-bit numbers:

• flags
• window type
• window manager menu information
• pushpin state information
• limited menu information

You don't have to fill in all the fields. Instead, you set the flags to a bit-mask specifying which fields are actually filled in:

The window types include the following:

To change window decorations, I normally use a type of _OL_WT_OTHER.

To add window decorations, fill in the _OL_DECOR_ADD property with the Atom IDs of the decorations you want to add to the default set.

To remove decorations, fill in the _OL_DECOR_DEL property with the Atom IDs of the decorations you want to remove.

Both properties contain any of the following Atoms: