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ghostscriptpostscriptimage-scaling

Scale PostScript Image via GhostScript

I have a postscript image, which I wanted to scale down to 84x84 pixels.

I tried the following line ( and different ones, but this one is the furthest I got ):

gs -sOutputFile=somefile.bmp -sDEVICE=bmpgray -q -g84x84 -dDEVICEWIDTH=84 -dDEVICEHEIGHT=84 -dPDFFitPage frames/frame_00000055.ps

This did not achieve what I wanted (all it does is showing a white image).

Solution

  • You have several problems with that command line. There is no command line switch -dDEVICEHEIGHT or -dDEVICEWIDTH, the relevant switches are -dDEVICEHEIGHTPOINTS and -dDEVICEWIDTHPOINTS. You should never attempt to set the media size in two different ways anwyay, it will only lead to problems of some kind. You've specified -dPDFFitPage, but you appear to have supplied a PostScript program as the input.

    Unsurprisingly, the PDFFitPage parameter does not scale PostScript.

    When you are having problems of any kind, its best not to mute the application using -q (for quiet), in case its trying to tell you something.

    Try using -dFitPage instead of -dPDFFitPage. If that still doesn't work, then I'll need to see your PostScript program.

    84x84 pixels is tiny, its entirely conceivable that the result of downscaling a PostScript program could result in no pixel centers being touched, in which case the output will indeed be blank.