AVS Modules						read compressed image
Lawrence Berkeley Laboratory					  24 Jan 1992

NAME
     read compressed image - read compressed image file from disk into a field

SUMMARY
     Name	   read	compressed image

     Type	   data

     Inputs	   none

     Outputs	   field 2D 4-vector byte

     Parameters	   _N_a_m_e		   _T_y_p_e		  _D_e_f_a_u_l_t	 _M_i_n	   _M_a_x
		   Input File	   Browser	  not applicable

DESCRIPTION
     The "read compressed image" module provides the same functionality
     as the AVS-supplied "read image" module, with the added twist that
     the image is in a "compressed" format.

     An AVS image may be compressed using the UNIX(tm) compress utility,
     or by using the sibling module "write compressed image."  Compression
     ratios of 1:10 are easily achieved using this compression scheme.

     Upon entrance to the computation function, this module first checks
     to see if the user-specified file has a ".Z" suffix.  If no .Z
     suffix is present, the module complains then quits.

     If the required suffix is present, the (compressed) file is copied
     to a temporary location (in /tmp, though this may be changed by a
     a recompilation), decompressed then read in.  System difficulties
     are accompanied by module failure.

PARAMETERS

     Input Image
	  The name of the compressed image file.

OUTPUTS

     Output Image
	The standard AVS image; 2D 4-vector byte field.


RELATED	MODULES
     write compressed image, read image, write image

SEE ALSO
     UNIX(tm) compress, uncompress

AVS Modules						read compressed image
Lawrence Berkeley Laboratory					  24 Jan 1992

24 Jan 1992

The source code, image_io.c, contains two very useful modules.
They will read and write compressed AVS image files, where the
UNIX-supplied un/compress are used for un/compressing the
.x files.

These modules have been tested on Sun and Stardent, uh, KPC Titan machines.
They HAVE NOT BEEN TESTED on anything alse.

wes