Rgbatrans can take input either from stdin or from a file specified on the command line. If a filename appears on the command line, stdin will not be checked for input. Filenames must appear before numeric arguments. The last optional argument specifiesthe opaqueness level to which to set the selected pixels. It still functions when considering colormap operations.
Output is directed to stdout and errors to stderr.
This will degrade the image quality considerably. Rgbatrans below is setting an absolute transparency value. Therefore, the input file cannot begin with any of these else it would be mistakenly taken as the first numeric argument. All rights reserved.