
plscompression: Set device-compression level 

DESCRIPTION:

    This function is used in example 31. 

SYNOPSIS:

plscompression(compression)

ARGUMENTS:

    compression (PLINT, input) :    The desired compression level. This is
    a device-dependent value. Currently only the jpeg and png devices
    use these values. For jpeg  value is the jpeg quality which should
    normally be in the range 0-95. Higher values denote higher quality
    and hence larger image sizes. For png values are in the range -1
    to 99. Values of 0-9 are taken as the  compression level for zlib.
    A value of -1 denotes the default zlib    compression level. Values
    in the range 10-99 are divided by 10 and  then used as the zlib
    compression level. Higher compression levels correspond to greater
    compression and small file sizes at the expense of more
    computation. 
