#
# usage.txt
# 
# Copyright (c) 1997-1999  Everett Lipman
#
# This document is free software; you can redistribute it and/or
# modify it under the terms of the GNU General Public License
# as published by the Free Software Foundation; either version 2
# of the License, or (at your option) any later version.
# 
# This document is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
# 
# The GNU General Public License is available at
#
#    http://www.fsf.org/copyleft/gpl.html
#
# Alternatively, you can write to the 
#
#    Free Software Foundation, Inc.
#    59 Temple Place - Suite 330
#    Boston, MA  02111-1307, USA
#

#
# 9 May 1999
#

This file describes the usage of the programs sfwjpg, pwpjpg,
pwpext, and the Independent JPEG Group's jpegtran.


Limitations:

  The programs sfwjpg and pwpjpg convert from Seattle
  FilmWorks's private file formats to JFIF (JPEG File Interchange
  Format).  As far as I am aware, Seattle FilmWorks does not
  make public the specifications of these formats.  The format
  specifications were deduced by examining a number of
  .sfw and .pwp files, and may not be entirely accurate.  In
  particular, some .sfw files which were downloaded from the SFW
  web site were not properly converted to JFIF.  All .pwp files
  which were downloaded from SFW and tried have been converted
  without any problems.

  Converted images will need to be flipped vertically.  This can
  be done with jpegtran.  The jpegtran program is part of the
  Independent JPEG Group's free software, which can be obtained
  from

  ftp://ftp.uu.net/graphics/jpeg 

  pwpext is a UNIX (Bourne) shell script, and will not work unless
  pwpjpg and jpegtran are in the execution search path ($PATH) when
  it is invoked.


sfwjpg

  sfwjpg will take a single .sfw file and convert it into a
  .jpg (JFIF) file.  The image in the newly created .jpg file
  will then need to be flipped vertically.  sfwjpg takes one or
  two arguments, the name of the .sfw file to be converted, and
  an optional output file:

  sfwjpg mypic.sfw

  This will create the file mypic.jpg in the current directory.
  mypic.sfw will not be altered or removed.  Under Microsoft
  Windows, sfwjpg.exe must be invoked from the run window
  command line.

  sfwjpg mypic.sfw foo.jpg

  This will convert mypic.sfw and leave the result in foo.jpg.

  sfwjpg mypic.sfw -

  This will convert mypic.sfw and write the result to the standard
  output.


pwpjpg

  pwpjpg will take a .pwp file and extract the images in the
  file.  A .pwp file typically contains the scanned images from
  an entire roll of film.  The names of the images are contained
  within the .pwp file.  pwpjpg takes a single argument, the
  name of the .pwp file from which to extract the images:

  pwpjpg mypics.pwp

  This will extract all of the images contained in mypics.pwp
  and write them in the current directory as .jpg (JFIF) files.
  The file names will correspond to the names of the images
  stored in the .pwp file.  mypics.pwp will not be altered or
  removed.  Under Microsoft Windows, pwpjpg.exe must be invoked
  from the run window command line.


pwpext

  pwpext is a UNIX (Bourne) shell script which extracts and
  flips the images from a .pwp file.  It takes a single
  argument, the name of the .pwp file:

  pwpext mypics.pwp

  This will extract, flip, and store as .jpg files all of the
  images contained in mypics.pwp.  mypics.pwp will not be
  altered or removed.


jpegtran

  jpegtran will do a lossless vertical inversion of the image in
  a .jpg file.  This is a complicated process which is described
  in details.txt.  jpegtran can use use standard input and output:

  jpegtran -flip vertical < mypic.jpg > myflippedpic.jpg

  This will create the file myflippedpic.jpg, which will contain
  the same image as mypic.jpg, except that the vertical ordering
  of the scan lines will be reversed in myflippedpic.jpg.  This
  flipping can be done by most image processing programs, though
  usually not without some gain in file size and/or loss in
  image quality.