Colours are the deeds of light; its deeds and sufferings: thus considered we may expect from them some explanation respecting light itself.
rgb] [-h ] [-n
registration] [-u ] [-v ] [-V ] [
The xycpt program generates discrete or continuous cpt files from simple input describing sample values of the colour (or greyscale) range. The input consists of 1–4 columns. For 2 and 4 columns, the first column is interpreted as a (double) z value, for 1 and 3 the z value is taken implicitly. For 1 and 2 columns the final column will be taken as a greyscale value. For 3 and 4, the last 3 columns are taken as RGB values.
The program will read from
stdin if a file is not specified as
the final argument, and write to
stdout if the
-o option is not specified.
In the following, all
rgb specifications should be
of the form
blue where the
colour components are integers in the range 0 to 255.
Set the background colour of the output.
Specify a file to which to write a formatted backtrace. The file will only be created if there is a backtrace created, typically when an error occurs.
formatof the backtrace written to the files specified by
--backtrace-file, one of
Output a discrete cpt file, the default is continuous.
Set the foreground colour of the output.
Set the NaN (no data) colour of the output.
Write the output to
file, rather than
For discrete (using the
-doption) conversion, specifies
lowerregistration of the data value. For the
lowertypes the final (respectively the first) colour is omitted from the output; only the z value is used. For
middleregistration all the colours appear in the output.
Colour values are specified as floating point numbers in the range 0–1 rather than as integers in the range 0–255.