X Window System Problems

Its getting harder and harder to write cross-platform X code that works perfectly. Some subtle differences have crept into different versions of X and these are hard to deal with in a general way. Please note the following problems and workarounds:

Netscape 4.0.x problems

Please note that versions 4.0.3 and 4.0.4 of Netscape ignore the -ncols switch that limits the number of colors hogged by the program. Therefore, when you are running Netscape 4.0.x, SAOtng will not be able to allocate colors from the public colormap and will be forced to switch to a private colormap. There is no work-around for this anti-social behavior on the part of Netscape. (Note that Netscape 3.x works properly.)

Arrow keys

Arrow keys are used in SAOtng to move the mouse or markers. X defines two sets of arrow keys: those situated on the keypad and those which are situated by themselves. Different keyboards might have one or both of these arrow key sets (e.g., most newer Sun keyboards have both, some Alpha keyboards have only the non-keypad keyboards), and different versions of X support one or both sets of definitions. Unfortunately, error messages are generated if both sets are defined in the SAOtng code but are not supported by X.

To get around this problem, we have added the -kbprefix command switch (and the SAOTNG_KBPREFIX environment variable) to SAOtng. This switch allows you to specify which arrow keys you want to use (assuming your version of X supports both). The default is set based on which version of X we believe you are using, so it often will be correct. But if your mouse and markers do not move in response to the arrow keys, please try one of these switches:

  saotng -kbprefix ""   # use the non-keypad keys
or
  saotng -kbprefix "KP_"  # use the keypad keys

If you find that one of them enables marker movement, then set the appropriate environment variable, for example:

  setenv SAOTNG_KBPREFIX "KP_"  

Note that using the wrong keyboard prefix can result in a lot of "translation table" error messages on startup. These messages look like:

Warning: translation table syntax error: Unknown keysym name: KP_Down

If you find that such error messages are being output, then try the other prefix. In the above example, the "KP_" prefix is not valid, so try:

  saotng -kbprefix ""

If nothing works (i.e., markers do not move or you get error translation messages on startup), please contact us.

Fonts

We have tried to use good-looking fonts that are defined on all X platforms, but we know we will be surprised some day. The two main fonts we use are:

  For menus: -adobe-times-bold-r-normal--14-140-75-75-p-77-iso8859-1
  For commands: -adobe-times-medium-r-normal--14-140-75-75-p-74-iso8859-1

The choice of these fonts can be controlled by the command switches: -menufont and -commandfont, or the corresponding environment variables: SAOTNG_MENUFONT and SAOTNG_COMMANDFONT.

In addition, the message window, dialog window, control panel and WCS display use fonts which can be specified using the -largefont1 (SAOTNG_LARGEFONT1), -smallfont1 (SAOTNG_SMALLFONT1), -smallfont2 (SAOTNG_SMALLFONT2), and -smallfont3 (SAOTNG_SMALLFONT3) switches (and environment variables):

  SmallFont1: -adobe-times-medium-r-normal--12-120-75-75-p-64-iso8859-1
  SmallFont2: -adobe-times-bold-r-normal--12-120-75-75-p-67-iso8859-1
  SmallFont3: 7x13bold
  LargeFont1: 9x15

These fonts look nice and natural on SAOtng, but X will substitute really ugly fonts if it can't locate them. If you find the font size is weird or really ugly, you can change fonts using the switches above. To see which fonts are available with your X server, execute the following X program in your shell:

  xlsfonts

Last Updated March 26, 1998