Installing dvipng
*****************

Installing dvipng should be simple: merely ‘./configure’, ‘make’, and
‘make install’.

Prerequisites
=============

   • The GD Graphics Draw library, libgd

     The drawing library ‘libgd’ is necessary, and is downloadable at
     <https://bitbucket.org/libgd/gd-libgd/downloads>, and there are
     binary packages for most operating systems from their respective
     distributors.  In any case, the library installs using ‘autoconf’
     so it should not be difficult for you to install it from source,
     and then proceed with installing dvipng.

   • The path-searching library kpathsea

     Kpathsea is most likely included in your LaTeX installation, but it
     may happen that ./configure does not find it; see below.  If you do
     not have it, download it from <http://www.ctan.org> and compile it.
     I have no experience with this, so I cannot help much here.

   • The font-rendering library FreeType 2

     While not strictly necessary, a recent FreeType 2 is recommended
     since dvipng currently will produce better-quality images when this
     library is available.  To take advantage of this, you should have
     at least FreeType 2.1.9.

     FreeType 2 will enable direct support for PostScript and TrueType
     fonts, so that dvipng will not need to generate bitmapped variants
     on disk of the TeX fonts since modern TeX distributions include
     PostScript versions of them.  Then, you can render images at
     different (and unusual) resolutions without cluttering the disk
     with lots of bitmapped fonts.

     Finally, it will enable subfont support in dvipng.  That is, if you
     want to render CJK-LaTeX characters, you must have FreeType 2
     installed.

   • libpng and libz

     To be able to compress and write PNG files to disk, dvipng (or
     really libgd) uses libpng which in turn uses libz.  These should be
     available on any modern system, if not, download them and install
     them.

   • The ‘texinfo’ package

     This is needed for building the documentation.

Configure
=========

The first step is to configure the source code, telling it where various
files will be.  To do so, run

     ./configure OPTIONS

   (Note: if you have fetched dvipng from CVS rather than a regular
release, you will have to first generate ‘./configure’ by running
‘autoconf’ 2.53 or later.)

   On many machines, you will not need to specify any options, but if
‘configure’ cannot determine something on its own, you'll need to help
it out.  For a list of the options type

     ./configure --help

   On some machines, the libraries will be installed in directories that
are not in the linker's search path.  This will generate an error when
running ‘./configure’, indicating that it cannot find libgd or
libkpathsea (most likely).  You then need to specify the path to the
respective library's object files.  They are typically called e.g.,
‘libgd.a’ or ‘libgd.so’.  If they are located in e.g., ‘/sw/local/lib’,
do

     ./configure LDFLAGS=-L/sw/local/lib

   If the library is available as a shared object file (‘.so’), the
runtime linker may also need to be told where to find the library, then
use

     ./configure LDFLAGS='-L/sw/local/lib -R/sw/local/lib'

   When either of these is necessary, it is likely that the C header
files are also installed in directories that are not in the C
preprocessor's search path.  This will also generate an error when
running ‘./configure’, indicating that it cannot find e.g., ‘gd.h’ or
‘kpathsea.h’ (most likely).  You then need to specify the path to the
respective library's C header files.  If they are located in e.g.,
‘/sw/local/include’, do

     ./configure CPPFLAGS=-I/sw/local/include

   On my SUN Solaris workstation, I had to combine this into

     ./configure CPPFLAGS='-I/sw/local/include -I/sw/tex/teTeX/1.0/include'\
         LDFLAGS='-L/sw/local/lib -R/sw/local/lib -L/sw/tex/teTeX/1.0/lib/'

where the backslash denotes a continuation of the line.

Build/install
=============

Once ‘configure’ has been run, simply enter

     make

at the prompt to compile the C code, and build the documentation files.
To install the files into the locations chosen earlier, type

     make install

You may need special privileges to install, e.g., if you are installing
into system directories.

Installation outside the texmf tree
===================================

In some cases, a dvipng binary installed outside the texmf tree will not
be able to find virtual fonts, or the PostScript font maps (normally
used by dvips).  This may be because _only_ $SELFAUTOLOC, $SELFAUTODIR,
and $SELFAUTOPARENT are used in the texmf tree configuration file
‘texmf.cnf’.  If so, give the switch ‘--enable-selfauto-set’ to
‘./configure’.  This will make dvipng adjust these three internally so
that kpathsea thinks that dvipng _is_ installed in the texmf tree.

Installation for non-privileged users
=====================================

Often people without system administration privileges want to install
software for their private use.  In that case you need to specify more
options to the ‘configure’ script, usually this is done by using the
‘--prefix’ option to the ‘configure’ script, and let it point to the
personal home directory.  In that way, resulting binaries will be
installed under the ‘bin’ subdirectory of your home directory, manual
pages under ‘man’ and so on.  That way, it is reasonably easy to
maintain a bunch of additional packages, since the prefix argument is
supported by most ‘configure’ scripts.

   You'll have to add something like ‘/home/myself/bin’ to your ‘PATH’
shell variable, if it isn't there already, and similarly set the
‘INFOPATH’ and ‘MANPATH’ variables to be able to access the
documentation.

Copying
=======

This program is released under the GNU Lesser General Public License
version 3, see the COPYING file in the dvipng distribution or
<http://www.gnu.org/licenses/>.

   Copyright © 2002-2015, 2019 Jan-Åke Larsson
