Set the background color by 8-bit rgb value and double alpha transparency value.
plscolbga(r, g, b, alpha)
Set the background color (color 0 in color map 0) by 8-bit RGB value (see the PLplot documentation) and double alpha transparency value.
This function is used in example 31.
r (PLINT, input)
Unsigned 8-bit integer (0-255) representing the degree of red in the color.
g (PLINT, input)
Unsigned 8-bit integer (0-255) representing the degree of green in the color.
b (PLINT, input)
Unsigned 8-bit integer (0-255) representing the degree of blue in the color.
alpha (PLFLT, input)
double value (0.0-1.0) representing the alpha transparency value of the color.
Many developers (who are credited at http://plplot.sourceforge.net/credits.php) have contributed to PLplot over its long history.
PLplot documentation at http://plplot.sourceforge.net/documentation.php.