- In some cases when an error occurs reading those parts of a JPEG

[imager.git] / README

================================================================
Copyright (c) 1999-2004 Arnar M. Hrafnkelsson. All rights reserved.
Copyright (c) 2004-2007 Anthony Cook.
This program is free software; you can redistribute it and/or
modify it under the same terms as Perl itself.
================================================================

>> THIS SOFTWARE COMES WITH ABSOLUTELY NO WARRANTY WHATSOEVER <<

If you like or hate Imager, please let me know by sending mail 
to imager@imager.perl.org - I love feedback.

================================================================


========================
1. Patent infringements?
========================

Imager as such contains no patented algorithms.  The external
libraries (which are not written by me) may or may not contain
patented algorithms.  YOU ARE SOLELY RESPONSIBLE FOR OBTAINING
LICENSE(S) TO USE SUCH LIBRARIES SHOULD YOU NEED ANY.


========================
2. Compiling and testing
========================

Some care has been taken to make the installation as smooth as
possible.  This is rather hard due to the difference between operating
systems and site setups.  To get started just type

$ perl Makefile.PL

It should blurb out a list of which libraries were found and which
not.  If you add a library to the machine after installing Imager it
does not automatically become available in Imager.  It only uses the
libraries that are found.  If the list of found libraries is not what
you expected, then the Makefile.PL is either not searching in the
right directories or your box does not have the libraries you think it
does.  For a list of where to get the libraries have a look at
3. External dependencies.  To widen the search path for libraries and
include files set the IM_INCPATH and IM_LIBPATH variables.  The
environment variables that matter when Makefile.PL is run are

IM_INCPATH      colon separated list of paths to extra include files
IM_LIBPATH      colon separated list of paths to extra library files

IM_VERBOSE      turns on verbose mode for the library scanning and such
IM_MANUAL       to manually select which libraries are used and which not
IM_NOLOG        if true logging will not be compiled into the module
IM_DEBUG_MALLOC if true malloc debugging will be compiled into the module
                do not use IM_DEBUG_MALLOC in production - this slows
                everything down

IM_CFLAGS       Extra flags to pass to the compiler
IM_LFLAGS       Extra flags to pass to the linker
IM_DFLAGS       Extra flags to pass to the preprocessor



When finding the libraries has been sorted out it's time for

$ make 

and if that works then do

$ make test

If either fails do take a peek at the file errep.perl.  It's creates a
file report.txt.  This is some information which will help me discover
where the problem is so I can try to fix it in future releases.  If
you find running it ok (just remember - no warranty!) please send the
report.txt via email to imager@imager.perl.org.

Troubleshooting tips:

A common problem is that libgif/libungif are sometimes linked to the X
libraries and then running the tests fails.  In that case something
like:

$ IM_LFLAGS="-L/usr/X11R6/lib -lX11" perl Makefile.PL

Which simply sets the environment variables for the extra libraries 
to include the X libraries (which we do not use at all, but must
included since libgif has been linked with it).

Otherwise you could just build giflib without any X11 dependencies:

  # must be a clean tree
  cd giflib-4.1.4
  ./configure --without-x ...

Also note that libgif has a few bugs: You can run something like

$ perl -Iblib/lib -Iblib/arch t/t105gif.t

This way you can see what comments the test script prints out.
t/t105gif.t checks for an bug in libgif and prints out a patch
if that bug is present, note that this bug only affects the more
"advanced" features of libgif.

If for some reason you have libungif-devel package installed but
not libungif on RedHat then you will probably get lots of errors
like undefined symbol: FreeSavedImages when running make test.
Install libungif package to fix it.

Stock libungif 4.1.4 or later seems to fix all of the bugs, if you
have a problem that version of linungif (or later), let us know and
we'll look into it.

Imager needs to have a libtiff version of at least 3.5.5, but you
should use a later version since some noticable bugs have been fixed.

For now you can either configure Imager manually (by setting the
IM_MANUAL environment variable to 1, in sh:

$ IM_MANUAL=1 perl Makefile.PL

and simply say no to tiff support when asked if you want it, the same thing
can be used to circumvent problems in gifs to get Imager going.

If it worked just continue with the installation as normally 
(with make install).

Freetype 1.x vs Freetype 2.x
----------------------------

These two libraries have some conflicting include file names, but as
long as you don't put the Freetype 2.x freetype.h directory in the
include path it should all work.

Put the directory containing ft2build.h in the include path, but not
the directory containing the freetype 2.x freetype.h.

If you see compilation errors from font.c you've probably made the
mistake of putting the Freetype 2.x freetype.h directory into the
include path.

To see which directories should be in the include path, try:

  freetype-config --cflags

Ideally, freetype-config should be in the PATH when building Imager
with freetype 2.x support.


Macintosh dfont and suitcase font support
-----------------------------------------

Through Freetype 2.1, Imager can use Macintosh DFON (.dfont) fonts and
suitcase font files.

If you want to be able to use more than just the first face in the
font file though, you will need to configure freetype2 with the
--with-old-mac-fonts option:

  ./configure --with-old-mac-fonts

You can use the index option to get to the other font faces in the
file:

  # get the second face from $file
  my $font = Imager::Font->new(file=>$file, index=>1)
    or die Imager->errstr;

If you're using a suitcase font, you will also need to force the use
of freetype 2 with the type argument:

  my $font = Imager::Font->new(file=>$suitcase, type=>'ft2', index=>$index)
    or die Imager->errstr;


========================
3. External dependencies
========================

Some hints about getting the Imager module to find the libraries it
needs for specific features.  The libraries it uses are:

 jpeg: http://www.ijg.org/files/
       ftp://ftp.uu.net/graphics/jpeg/jpegsrc.v6b.tar.gz

ftp.uu.net is still linked from many places, including the Independent
JPEG Groups's home page, but it is non-functional.

  png: http://www.libpng.org/pub/png/libpng.html

  you also need zlib to use png:  http://www.gzip.org/zlib/
We have encountered problems with libpng 1.0.1, which were fixed in 1.0.5
Note: you should probably be using zlib 1.1.4, since 1.1.3 has a 
potential security problem.

  gif: http://sourceforge.net/projects/libungif

giflib/libungif has come a long way since the buggy versions available
when Imager's gif support code was written.  Preferably you should get
at least version 4.1.4.  If you have a recent Linux distribution you
should be safe with whatever giflib it provides, but if you're
building from source, please try to use the latest version.

libgif 4.1.4 has no problems known to me at this point.

 tiff: http://www.libtiff.org/

   t1: http://www.ibiblio.org/pub/Linux/libs/graphics/

freetype2 or
   tt: http://www.freetype.org/

Precompiled versions of some of the libraries might be found at:

AIX:
   http://www.bullfreeware.com/



========================
4. Logging and debugging
========================

Logging is compiled in by default - if you should want to get of it
from the binaries you can do so by setting the env IMAGER_NOLOG 
to something. If you want to enable malloc debugging to check for leaks
then set IMAGER_DEBUG_MALLOC to something.  Needless to say it is
pretty pointless to have malloc debug enabled with no logging since you 
can never see the malloc information that way.


=================
5. Win32 Support
=================

Imager can be installed on Win32 systems.  This was ported and tested
with Microsoft Visual C++ 6.0 with build 623 of ActivePerl.  You can
use all of the features of Imager.  You can also use Win32 GDI fonts
directly by supplying the 'face' parameter to Imager::Font->new(...).

I've tested with both MSVC++ 6.0 and cygwin (perl 5.6.1).

If you see an error under cygwin during testing along the lines of:

  C:\cygwin\bin\perl.exe: *** unable to remap C:\cygwin\...some dll to the 
    same address as parent (0x...) != 0x....

you will need to install the cygwin rebase package and run:

  $ rebaseall -v

If you get errors from your make tool, make sure you're using the same
make that was used to build your perl - generally GNU make for cygwin,
nmake for Visual C/C++ and dmake for MinGW.

============
6. Mac OS X
============

Building Imager under OS X is generally straightforward.  There are
some exceptions though:

a) you may find to need to ranlib library files in place after you've 
   installed them, for example:

     ranlib /usr/local/lib/libgif.a

b) the version of GCC enabled by default on OS X 10.4 generates
   incorrect code for some functions.  To work around this run:

     gcc_select 3

   before building Imager and:

     gcc_select 4

   after building Imager.

   This problem exhibits itself as test failures in t/t20fill.t

   Imager 0.56 includes a workaround for this problem, but I wasn't
   able to test it.

c) if you want to build GCC 4.0 from scratch and use that you will
   need to adjust the command-line supplied during the link stage, so
   that there is some other option before the -bundle option.

   For example:

     perl Makefile.PL LDDLFLAGS="`perl -MConfig -e 'print "-g $Config{lddlflags}"'`"
   
=======================
7. General information
=======================

The Imager module homepage is currently at:

 http://imager.perl.org/

You can report bugs by pointing your browser at:

  https://rt.cpan.org/NoAuth/ReportBug.html?Queue=Imager

========================
8. Thanks
========================

Thanks go to:
  Tony Cook           ( TonyC )
  Claes Jacobson      ( Claes )
  Philip Gwyn         ( Leolo )
  Michael Slade       ( Micksa )
                      ( Cogent )
  Brad Murray         ( HalfJack )
  Nicholas Dronen     ( Veblen )
  Michael G Schwern   ( Schwern )
  Rocco Caputo        ( Dngor )
  Graham barr         ( Gbarr )
  Mark-Jason Dominus  ( Mjd )
  Jerome
  Jason Alexander     ( Jalex )
  Randal R. Schwartz  ( Merlyn )
  Tkil                ( )
  Artur Bergman       ( Sky )
  Luc St-Louis        ( Lucs )
  PerlJam             ( )
  Roderick Schertler  ( Roderick )
  Nathan Torkington   ( gnat )

(and just to play it safe) all those I forgot to mention.