SETUP

SETUP instructions for the Independent JPEG Group's JPEG software
=================================================================

This file explains how to configure and compile the JPEG software.  We have
tried to make this software extremely portable and flexible, so that it can be
adapted to almost any environment.  The downside of this decision is that the
installation process is not very automatic; you will need at least a little
familiarity with C programming and program build procedures for your system.

This file contains general instructions, then sections of specific hints for
certain systems.  You may save yourself considerable time if you scan the
whole file before starting to do anything.

Before installing the software you must unpack the distributed source code.
Since you are reading this file, you have probably already succeeded in this
task.  However, there is one potential trap if you are on a non-Unix system:
you may need to convert these files to the local standard text file format
(for example, if you are on MS-DOS you probably have to convert LF end-of-line
to CR/LF).  If so, apply the conversion to all the files EXCEPT those whose
names begin with "test".  The test files contain binary data; if you change
them in any way then the self-test will give bad results.


STEP 1: PREPARE A MAKEFILE
==========================

First, select a makefile and copy it to "Makefile" (or whatever your version
of make uses as the default makefile name; for example, "makefile.mak" for
Borland C).  We include several standard makefiles in the distribution:

	makefile.ansi: for Unix systems with ANSI-compatible C compilers.
	makefile.unix: for Unix systems with non-ANSI C compilers.
	makefile.mc5:  for Microsoft C 5.x under MS-DOS.
	makefile.mc6:  for Microsoft C 6.x under MS-DOS.
	makefile.tc:   for Borland's Turbo C under MS-DOS.
	makefile.pwc:  for Mix Software's Power C under MS-DOS.
	makefile.manx: for Manx Aztec C on Amigas.
	makefile.sas:  for SAS C on Amigas.

If you don't see a makefile for your system, we recommend starting from either
makefile.ansi or makefile.unix, depending on whether your compiler accepts
ANSI C or not.  Actually you should start with makefile.ansi whenever your
compiler supports ANSI-style function definitions; you don't need full ANSI
compatibility.  The difference between the two makefiles is that makefile.unix
preprocesses the source code to convert function definitions to old-style C.
(Our thanks to Peter Deutsch of Aladdin Enterprises for the ansi2knr program.)

If you don't know whether your compiler supports ANSI-style function
definitions, then take a look at config.c.  It is a test program that will
help you figure out this fact, as well as some other facts you'll need in
later steps.  You must compile and execute config.c by hand; the makefiles
don't provide any support for this.  config.c may not compile the first try
(in fact, the whole idea is for it to fail if anything is going to).  If you
get compile errors, fix them by editing config.c according to the directions
given in config.c.  Once you get it to run, select a makefile according to the
advice it prints out, and make any other changes it recommends.

Look over the selected Makefile and adjust options as needed.  In particular
you may want to change the CC and CFLAGS definitions.  For instance, if you
are using GCC, set CC=gcc.

If you are on a system that doesn't use makefiles, you'll need to set up
project files (or whatever you do use) to compile all the source files and
link them into executable files cjpeg and djpeg.  See the file lists in any of
the makefiles to find out which files go into each program (makcjpeg.lst and
makdjpeg.lst are handy summaries).


STEP 2: EDIT JCONFIG.H
======================

Look over jconfig.h and adjust #defines to reflect the properties of your
system and C compiler.  (If you prefer, you can usually leave jconfig.h
unmodified and add -Dsymbol switches to the Makefile's CFLAGS definition.)

If you have an ANSI-compliant C compiler, no changes should be necessary
except perhaps for RIGHT_SHIFT_IS_UNSIGNED and TWO_FILE_COMMANDLINE.  For
older compilers other changes may be needed, depending on what ANSI features
are supported.

If you don't know enough about C programming to understand the questions in
jconfig.h, then use config.c to figure out what to change.  (See description
of config.c in step 1.)

A note about TWO_FILE_COMMANDLINE: defining this selects the command line
syntax in which the input and output files are both named on the command line.
If it's not defined, the output image goes to standard output, and the input
can optionally come from standard input.  You MUST use two-file style on any
system that doesn't cope well with binary data fed through stdin/stdout; this
is true for most MS-DOS compilers, for example.  If you're not on a Unix
system, it's probably safest to assume you need two-file style.


STEP 3: MAKE
============

Now you should be able to "make" the software.

If you have trouble with missing system include files or inclusion of the
wrong ones, look at jinclude.h (or use config.c, if you are not a C expert).

If your compiler complains about big_sarray_control and big_barray_control
being undefined structures, you should be able to shut it up by adding
-DINCOMPLETE_TYPES_BROKEN to CFLAGS (or add #define INCOMPLETE_TYPES_BROKEN
to jconfig.h).

There are a fair number of routines that do not use all of their parameters;
some compilers will issue warnings about this, which you can ignore.  Any
other warning deserves investigation.


STEP 4: TEST
============

As a quick test of functionality we've included three small sample files:
	testorig.jpg	A reduced section of the well-known Lenna picture.
	testimg.ppm	The output of djpeg testorig.jpg
	testimg.jpg	The output of cjpeg testimg.ppm
(The two .jpg files aren't identical since JPEG is lossy.)  If you can
generate duplicates of testimg.ppm and testimg.jpg then you probably have a
working port.

With most of the makefiles, "make test" will perform the necessary
comparisons.  If you're using a makefile that doesn't provide this option, run
djpeg and cjpeg to generate testout.ppm and testout.jpg, then compare these to
testimg.* with whatever file comparison tool you have.  The files should be
bit-for-bit identical.

NOTE: this is far from an exhaustive test of the JPEG software; some modules,
such as color quantization and GIF I/O, are not exercised at all.  It's just a
quick test to give you some confidence that you haven't missed something
major.

If the test passes, you can copy the executable files cjpeg and djpeg to
wherever you normally install programs.  Read the file USAGE to learn more
about using the programs.


OPTIONAL STUFF
==============

We distribute the software with support for RLE image files (Utah Raster
Toolkit format) disabled, because the RLE support won't compile without the
Utah library.  If you have URT version 3.0, you can enable RLE support as
follows:
	1.  #define RLE_SUPPORTED in jconfig.h or in the Makefile.
	2.  Add a -I option to CFLAGS in the Makefile for the directory
	    containing the URT .h files (typically the "include"
	    subdirectory of the URT distribution).
	3.  Add -L... -lrle to LDLIBS in the Makefile, where ... specifies
	    the directory containing the URT "librle.a" file (typically the
	    "lib" subdirectory of the URT distribution).

If you want to incorporate the JPEG code as subroutines in a larger program,
we recommend that you make libjpeg.a.  Then use the jconfig.h and jpegdata.h
files as your interface to the JPEG functions, and link libjpeg.a with your
program.  Your surrounding program will have to provide functionality similar
to what's in jcmain.c or jdmain.c, and you may want to replace jerror.c and
possibly other modules depending on your needs.  See the "architecture" file
for more info.  If it seems to you that the system structure doesn't
accommodate what you want to do, please contact the authors.

CAUTION: When you use the JPEG code as subroutines, we recommend that you make
any required configuration changes by modifying jconfig.h, not by adding -D
switches to the Makefile.  Otherwise you must be sure to provide the same -D
switches when compiling any program that includes the JPEG .h files.

If you need to make a smaller version of the JPEG software, some optional
functions can be removed at compile time.  See the xxx_SUPPORTED #defines in
jconfig.h.  If at all possible, we recommend that you leave in decoder support
for all valid JPEG files, to ensure that you can read anyone's output.
Restricting your encoder, or removing optional functions like block smoothing,
won't hurt compatibility.  Taking out support for image file formats that you
don't use is the most painless way to make the programs smaller.


NOTES FOR SPECIFIC SYSTEMS
==========================

We welcome reports on changes needed for systems not mentioned here.
Submit 'em to jpeg-info@uunet.uu.net.  Also, config.c is fairly new and not
yet thoroughly tested; if it's wrong about how to configure the JPEG software
for your system, please let us know.


HP/Apollo DOMAIN:

At least in version 10.3.5, the C compiler is ANSI but the system include
files are not.  Use makefile.ansi and add -DNONANSI_INCLUDES to CFLAGS.

HP-UX:

If you have HP-UX 7.05 or later with the "software development" C compiler,
then you can use makefile.ansi.  Add "-Aa" to the CFLAGS line in the
makefile.  If you have a pre-7.05 system, or if you are using the non-ANSI C
compiler delivered with a minimum HP-UX 8.0 system, then you must use
makefile.unix (and do NOT add -Aa).  Also, adding "-lmalloc" to LDLIBS is
recommended if you have libmalloc.a (it seems not to be present in minimum
8.0).

On HP series 800 machines, the HP C compiler is buggy in revisions prior to
A.08.07.  If you get complaints about "not a typedef name", you'll have to
convert the code to K&R style (i.e., use makefile.unix).

IBM RS/6000 AIX:

The CFLAGS switch to make the compiler define __STDC__ is "-qlanglvl=ansi".

Macintosh Think C:

You'll have to prepare project files for cjpeg and djpeg; we don't include
those in the distribution since they are not text files.  The COBJECTS and
DOBJECTS lists in makefile.unix show which files should be included in each
project.  Also add the ANSI and Unix C libraries in a separate segment.  You
may need to divide the JPEG files into more than one segment; you can do this
pretty much as you please.

If you have Think C version 5.0 you should be able to just turn on __STDC__
through the compiler switch that enables that.  With version 4.0 you must
manually edit jconfig.h.  (You can #define __STDC__, but also #define const.)

Microsoft C for MS-DOS:

Some versions of MS C fail with an "out of macro expansion space" error
because they can't cope with the macro TRACEMS8 (defined in jpegdata.h).
If this happens to you, the easiest solution is to change TRACEMS8 to
expand to nothing.  You'll lose the ability to dump out JPEG coefficient
tables with djpeg -d -d, but at least you can compile.

Sun:

Don't forget to add -DBSD to CFLAGS.  If you are using GCC on SunOS 4.0.1 or
earlier, you will need to add -DNONANSI_INCLUDES to CFLAGS (your compiler may
be ANSI, but your system include files aren't).  I've gotten conflicting
reports on whether this is still necessary on SunOS 4.1 or later.