Tcl Image formats (Img)
		(Version 1.0b1 / March 12, 1997)

		Jan Nijtmans	(nijtmans@nici.kun.nl)

This file contains a collection of format handlers for Tk.
It can be used in combination with Tk4.1 or later. Also
supported are Itcl 2.1 (or later) and the Tcl/Tk netscape
plugin (version 1.1 or later).

Included in this distribution are the most recent versions
(as of March 26 '97) of the libz, libpng, libjpeg and libtiff
libraries. These are not required for compilation of libimg,
only if you need support for the PNG, JPEG or TIFF format.
If your system already has shared libraries for these formats,
probably it will already work with this package. Otherwise the
tools are here to build it any time later.

CONFIGURE

Configure has the following possibilities:

	configure --with-tcl=/usr/local/lib --with-tk=/usr/local/lib

The options --with-tcl and --with-tk are optional. The most recent
version of Tcl/Tk will be found automatically, either in a
sibling directory of the img1.0 top directory or in <exec-prefic>/lib.
Optional is the option "--enable-shared": it is already the default.
If you don't want shared libraries, use "--disable-shared". Configuration
of libtiff and libjpeg will be done automatically.

PATCH

In the patches subdirectory, a patch file "tk.patch" and a
source file "tkImgPhoto.c: is present. Either copy "tk.patch"
to the Tk distribution and type "patch <tk.patch", or copy
tkImgPhoto.c in the "generic" directory of any Tk version.
This will enhance the photo widget:
  - New image subcommand "data", which returns the content
    of the image as a string.
  - New "-format", "-grayscale" and "-background"
    options for the "data" and "write" subcommands.
  - Internal modification which allows writing of transparency
    information to disk or (base-64 encoded) strings.
The Img package can be built without this patch, only a lot
of tests will fail. But reading images from files will always
work, not matter if the patch is used or not.


MAKE

By default only libimg1.0.so will be built. If the Netscape Tcl/Tk plugin
is available in /usr/local/lib/netscape/plugins another library
"libimg.so" is built as well, which can be dynamically loaded in
the netscape plugin. Further on:

	make		build libimg1.0.so only
	make z		build libz.so
	make png	build libpng.so
	make jpeg	build libjpeg.so
	make tiff	build libtiff.so
	make all	build all of above
	make test	run tests for all image formats.

Best is to start with "make". If a test fails for one of the
PNG, JPEG or TIFF formats, the error message will indicate
what is wrong. If a library is missing in your system, you
can always build it later. If a crash occurs, this might
also indicate that you better upgrade one of these libraries.

If you prefer to use versions numbers after the extension, you
can manually adapte the Makefile. On Irix, you can use the
"ifl" libraries which are already part of the operating system.
The top of the Makefile shows which file names to use.

INSTALL

You can install whatever you like:
	make install		install libimg1.0.so only
	make install-z		install libz.so
	make install-png	install libpng.so
	make install-jpeg	install libjpeg.so
	make install-tiff	install libtiff.so
	make install-all	install all of above
	
PLATFORMS
	tested:
		Linux 1.2.13	(gcc 2.7.0)
		IRIX 6.2	(cc only)
		ULTRIX 4.1	(both cc and gcc)
		ULTRIX 4.4	(cc 3.0)
		HP-UX-9		(both cc and gcc 2.7.0)
		HP-UX-10.2	(gcc 2.7.2)
		Solaris 2.5	(gcc 2.7.2 only)
		Windows	95/NT	(MS Visual C++ 4.2, Windows NT 3.51)

	Not done yet:
		Mac		) someone interested
		VMS		) to try??????

	Other machines and OS's should work too. 

Feedback about other OS's and compilers is appreciated. Please
help me in making this package better.

THANKS

Many thanks to Andreas Kupries <a.kupries@westend.com> for many
feedback and all the makefiles for Windows (MS Visual C++ 4.2).

		Jan Nijtmans
		NICI (Nijmegen Institute of Cognition and Information
		email: nijtmans@nici.kun.nl
		url:   http://www.cogsci.kun.nl/~nijtmans/