GraphicsMagick

Octave will use GraphicsMagick for reading and writing your images (not plots, only if you are actually doing image processing). This means that the GraphicsMagick configuration you have on you system will limit what your Octave installation can do. Most systems will have it onn their repositories. Unfortunately, their configuration is not always the best for image analysis as it limits reading of images to 8-bit.

Quantum depth

The most common problem is the following warning when using imread():

warning: your version of GraphicsMagick limits images to 8 bits per pixel

The reason for this is that GraphicsMagick was compiled with --with-quantum-depth 8. Possible values are 8, 16 or 32, each implememnting that limitation. See the INSTALL file on GraphicsMagick sourcefor an explanantion of this. There has bugs reported requesting package maintainers to compile it with higher values. You should not create a new bug, instead leave a comment on the already open bugs: Debian, Ubuntu.

As versions with higher values are not available on the repositories, the solution is to compile it. Octave needs then to be recompiled to use the freshly compiled Magick++ library.

Magick++

Magick++ is the C++ application programming interface to GraphicsMagick. This is what Octave uses so you will need this when compiling GraphicsMagick. This will be enabled by default but if you don't have a C++ compiler installed (such as g++) GraphicsMagick will build just fine without a warning, just a small note during the run of configure.

Shared libraries

The default is to disable shared libraries but that won't work with Octave. You will need to pass the --enable-shared option. If you do not, Octave will give the following warning when running configure:

GraphicsMagick++ library fails tests.  The imread function for reading image files will not be fully functional.

Dependencies

Compiling from source means tracking the dependencies yourself which may be a kind of painful. There's no wiki for GraphicsMagick so the following table hopes to makes things easier. Note however that this is the list of all dependencies and suggestions. For Octave purposes only, you definetely will not need all of these.

Dependency	Debian Wheezy	Ubuntu Precise
BZLIB	libbz2-dev	libbz2-dev
dcraw	dcraw	dcraw
dot	graphviz	graphviz
fig2dev	transfig	transfig
FlashPIX
FreeType 2.0	libfreetype6-dev	libfreetype6-dev
Ghostscript	ghostscript	ghostscript
Ghostscript-fonts	gsfonts	gsfonts
gnuplot	gnuplot	gnuplot
hp2xx	hp2xx	hp2xx
html2ps	html2ps	html2ps
JBIG	libjbig-dev
JPEG v1	libjpeg8-dev	libjpeg-dev
JPEG-2000	libjasper-dev	libjasper-dev
LCMS v2	liblcms2-dev	liblcms2-dev
ltdl	libltdl-dev	libltdl-dev
LZMA	liblzma-dev	liblzma-dev
PNG	libpng12-dev	libpng12-dev
ra_ppm	radiance	radiance
scanimage	sane-utils	sane-utils
TIFF	libtiff5-dev	libtiff5-dev
TRIO
WMF	libwmf-dev	libwmf-dev
X11	libx11-dev libxext-dev libsm-dev
XML	libxml2-dev	libxml2-dev
ZLIB	zlib1g-dev	zlib1g-dev

You will also need to install g++ and gcc (or alternatives).

DPS has been deprecated and should not be used hence why is not on the list.

Ghostscript library support is not recommended by GraphicsMagick hence why is not on the list.

there are both LCMS v2 and v1 but GraphicsMagick only needs one of them.