Common user interface
Nicolas Calimet <email@example.com>
Some of the featured POV-Ray / MegaPOV patches provide with additional facilities that are user-controlled via either environment variables or patch-specific command-line options. The first are set in the shell, while the second are passed to the command-line when invoquing the povray or megapov executable.
The user settings are identical regardless of the method used: the value passed to the environment variable or command-line option is the same text string. Quoting the option value may be necessary if the string contains spaces or other special characters.
Depending on your shell, environment variables are set as follows:
setenv VARIABLE "value"
where VARIABLE is for instance POV_STREAM_COLORS. The various environment variables recognized are presented in the relevant user manual for each patch.
Each environment variable has an equivalent command-line option.
Note: Using the command-line option always overrides the setting provided by the environment variable, if any.
Command-line options are available as several syntactic variants for conveniency. The recognized syntaxes differ by the number of leading dash characters (one or two), the use of dash or underscore to seperate the name components, and the use of spaces or an equal sign to seperate the value from the option name.
For instance, one can equally use any of the following syntaxes (use of equal sign or space is arbitrary here):
--pov-stream-colors="value" -pov-stream-colors "value" --pov_stream_colors="value" -pov_stream_colors "value"
Note: Command-line options cannot be abbreviated.
The last syntax is the most consistent with respect to the name of the related environment variable and the form of the standard POV-Ray command-line options. However the first form is encouraged for users who are familiar with programs that support GNU-style long options.