Environment Variables
Eric Pepke
September 11, 1992

Summary: Description of environment variables used by SciAn

SciAn uses a number of environment variables for debugging and for setting 
default parameters.  All variables begin with SCIAN_.

SCIAN_SHOW_CONFIG
   If this variable is defined (any definition will do), then SciAn will
   print to standard output the decisions it makes about the machine while
   setting it up.

SCIAN_VETO_RGB
   If this variable is defined, then SciAn will not use RGB mode even if it
   is present.

SCIAN_VETO_CMAP
   If this variable is defined, then SciAn will not use color map mode even
   if it is present.

SCIAN_VETO_DOUBLE
   If this variable is defined, then SciAn will not use double buffers even
   if it can.

SCIAN_VETO_ZBUFFER
   If this variable is defined, then SciAn will not use the Z-buffer even
   if there is one.

SCIAN_FORCE_ZBUFFER
   If this variable is defined, then SciAn will try to use the Z-buffer even
   if there isn't one.

SCIAN_VETO_OVERLAY
   If this variable is defined, then SciAn will not use overlay planes even
   if they are there.  This causes SciAn not to work most of the time.

SCIAN_FORCE_OVERLAY
   If this variable is defined, then SciAn will try to use overlay planes
   even if they are not there.

SCIAN_SCAVENGE_COLORS
   If this variable is defined, then SciAn will try to scavenge colors from
   the existing color map as much as it can instead of define new entries.
   This keeps the color map more pristine and may be a good idea on systems
   with not very much memory.  However, it may take longer.

SCIAN_COLOR_BEG
   This variable can be defined as an integer giving the start of the 
   colors in the color map that SciAn writes over for its own use.

SCIAN_N_COLORS
   This variable can be defined as the number of colors that SciAn can use.
   It overrides assumptions about the system.

SCIAN_RECORDER_DEV
   This variable should be a string which is the path of the terminal device
   used to drive a videodisc recorder connected to the machine.

SCIAN_preference
   Any variable of this form is a default preference if no preferences file
   is found.  Names and values of preferences can be found in 
   ScianPreferences.c.  Look for the shortName field of prefInfo.