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

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