PGPLOT Module: PGSCRN -- set color representation by name


Set color representation: i.e., define the color to be
associated with a color index. Ignored for devices which do not
support variable color or intensity. This is an alternative to
routine PGSCR. The color representation is defined by name instead
of (R,G,B) components.

Color names are defined in an external file which is read the first
time that PGSCRN is called. The name of the external file is
found as follows:
1. if environment variable (logical name) PGPLOT_RGB is defined,
its value is used as the file name;
2. otherwise, if environment variable PGPLOT_DIR is defined, a
file "rgb.txt" in the directory named by this environment
variable is used;
3. otherwise, file "rgb.txt" in the current directory is used.
If all of these fail to find a file, an error is reported and
the routine does nothing.

Each line of the file
defines one color, with four blank- or tab-separated fields per
line. The first three fields are the R, G, B components, which
are integers in the range 0 (zero intensity) to 255 (maximum
intensity). The fourth field is the color name. The color name
may include embedded blanks. Example:

255 0 0 red
255 105 180 hot pink
255 255 255 white
0 0 0 black

CI (input) : the color index to be defined, in the range 0-max.
If the color index greater than the device
maximum is specified, the call is ignored. Color
index 0 applies to the background color.
NAME (input) : the name of the color to be associated with
this color index. This name must be in the
external file. The names are not case-sensitive.
If the color is not listed in the file, the
color representation is not changed.
IER (output) : returns 0 if the routine was successful, 1
if an error occurred (either the external file
could not be read, or the requested color was
not defined in the file).