How do I set keys of Ghostscript filters (as documented here) in the command-line interface?
More precisely, I would like to set the
Predictor option of the
PNGPredictorEncode filter in the following script:
gs \ -sDEVICE=pdfwrite \ -dGrayImageFilter=/PNGPredictorEncode \ -sOutputFile=out.pdf \ in.pdf
I have tried to guess the syntax for this and found some ways which do not raise a syntax error (e.g., adding
-dPredictor=10 as an option). However, none of these ways seemed to have any effect (the respective
out.pdfs were identical to the pixel).