intn GRsetcompress(int32 ri_id, int32 comp_type, comp_info *c_info)

	ri_id	IN:	Raster image identifier returned by GRcreate or GRselect
	comp_type	IN:	Compression method for the image data
	C only:
	c_info	IN:	Pointer to the comp_info union
	Fortran only:
	comp_prm	IN:	Compression parameters array

	Purpose	Specifies if the raster image will be stored in a file as a compressed raster image.
	Return value	Returns SUCCEED (or 0) if successful and FAIL (or -1) otherwise.
	Description	GRsetcompress specifies if the raster image specified by the parameter ri_id will be stored in the file in compressed format.
		The compression method is specified by the parameter comp_type. Valid values of the parameter comp_type are:
		COMP_CODE_NONE (or 0) for no compression COMP_CODE_RLE (or 1) for RLE run-length encoding COMP_CODE_SKPHUFF (or 3) for Skipping Huffman compression COMP_CODE_DEFLATE (or 4) for GZIP compression
		The compression method parameters are specified by the parameter c_info in C and the parameter comp_prm in Fortran. The parameter c_info has type comp_info, which is described in the hcomp.h header file. It contains algorithm-specific information for the library compression routines.
		The skipping size for the Skipping Huffman algorithm is specified in the field c_info.skphuff.skp_size in C and in the parameter comp_prm(1) in Fortran.
		The deflate level for the GZIP algorithm is specified in the field c_info.deflate.level in C and in the parameter comp_prm(1) in the Fortran.

	FORTRAN	integer mgscompress(ri_id, comp_type, comp_prm)
		integer ri_id, comp_type, comp_prm(*)