libvips/README.md

# libvips : an image processing library

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libvips is a 2D image processing library. Compared to
similar libraries, [libvips runs quickly and uses little
memory](http://www.vips.ecs.soton.ac.uk/index.php?title=Speed_and_Memory_Use).
libvips is licensed under the LGPL 2.1+.

It has around 300 operations covering arithmetic, histograms,
convolutions, morphological operations, frequency filtering, colour,
resampling, statistics and others. It supports a large range of numeric
formats, from 8-bit int to 128-bit complex. It supports a good range of
image formats, including JPEG, TIFF, PNG, WebP, FITS, Matlab, OpenEXR,
PDF, SVG, HDR, PPM, CSV, GIF, Analyze, DeepZoom, and OpenSlide.  It can
also load images via ImageMagick or GraphicsMagick.

It has APIs for
[C](http://www.vips.ecs.soton.ac.uk/supported/current/doc/html/libvips/using-from-c.html)
and
[C++](http://www.vips.ecs.soton.ac.uk/supported/current/doc/html/libvips/using-from-cpp.html)
and comes with a [Python
binding](http://www.vips.ecs.soton.ac.uk/supported/current/doc/html/libvips/using-from-python.html)
and a [command-line
interface](http://www.vips.ecs.soton.ac.uk/supported/current/doc/html/libvips/using-cli.html).
Bindings are available for [Ruby](https://rubygems.org/gems/ruby-vips),
JavaScript and others. There is full
[documentation](http://www.vips.ecs.soton.ac.uk/supported/current/doc/html/libvips/index.html).
There are several GUIs as well, see the [VIPS
website](http://www.vips.ecs.soton.ac.uk).

There are packages for most unix-like operating systems and binaries for
Windows and OS X.

# Building libvips from a source tarball

We keep pre-baked tarballs of releases on the vips website:

http://www.vips.ecs.soton.ac.uk/supported/current/

Untar, then in the libvips directory you should just be able to do:

	$ ./configure

Check the summary at the end of `configure` carefully. 
libvips must have `build-essential`, `pkg-config`, `glib2.0-dev`, and 
`libxml2-dev`. 

For the vips8 Python binding, you must have 
`gobject-introspection`, `python-gi-dev`, and `libgirepository1.0-dev`.

You'll need the dev packages for the file format support you
want. For basic jpeg and tiff support, you'll need `libtiff5-dev`,
`libjpeg-turbo8-dev`, and `libgsf-1-dev`.  See the **Dependencies** section
below for a full list of the things that libvips can be configured to use.

Once `configure` is looking OK, compile and install with the usual:

	$ make
	$ sudo make install

By default this will install files to `/usr/local`.

We have detailed guides on the wiki for [building on
Windows](http://www.vips.ecs.soton.ac.uk/index.php?title=Build_on_windows)
and [building on OS
X](http://www.vips.ecs.soton.ac.uk/index.php?title=Build_on_OS_X).

# Building libvips from git

Checkout the latest sources with:

	$ git clone git://github.com/jcupitt/libvips.git

Building from git needs more packages, you'll need at least `swig`, `gtk-doc` 
and `gobject-introspection`, see the dependencies section below. For example:

	$ brew install gtk-doc swig

Then build the build system with:

	$ ./bootstrap.sh

Debug build:

	$ CFLAGS="-g -Wall" CXXFLAGS="-g -Wall" \
		./configure --prefix=/home/john/vips --enable-debug
	$ make
	$ make install

Leak check:

	$ export G_DEBUG=gc-friendly
	$ export G_SLICE=always-malloc
	$ valgrind --suppressions=libvips.supp \
		--leak-check=yes \
		vips ... > vips-vg.log 2>&1

valgrind threading check:

	$ valgrind --tool=helgrind vips ... > vips-vg.log 2>&1

Clang build:

	$ CC=clang CXX=clang++ ./configure --prefix=/home/john/vips

Clang static analysis:

	$ scan-build ./configure --disable-introspection
	$ scan-build -o scan -v make 
	$ scan-view scan/2013-11-22-2

Clang dynamic analysis:

	$ FLAGS="-O1 -g -fsanitize=address"
	$ FLAGS="$FLAGS -fno-omit-frame-pointer -fno-optimize-sibling-calls"
	$ CC=clang CXX=clang++ LD=clang \
		CFLAGS="$FLAGS" CXXFLAGS="$FLAGS" LDFLAGS=-fsanitize=address \
		./configure --prefix=/home/john/vips 

	$ FLAGS="-O1 -g -fsanitize=thread"
	$ FLAGS="$FLAGS -fPIC -pie"
	$ FLAGS="$FLAGS -fno-omit-frame-pointer -fno-optimize-sibling-calls"
	$ CC=clang CXX=clang++ LD=clang \
		CFLAGS="$FLAGS" CXXFLAGS="$FLAGS" \
		LDFLAGS="-fsanitize=thread -fPIC -pie" \
		./configure --prefix=/home/john/vips 

Build with the GCC auto-vectorizer and diagnostics (or just -O3):

	$ FLAGS="-O2 -msse4.2 -ffast-math"
	$ FLAGS="$FLAGS -ftree-vectorize -fdump-tree-vect-details"
	$ CFLAGS="$FLAGS" CXXFLAGS="$FLAGS" \
		./configure --prefix=/home/john/vips 

Static analysis with:

	$ cppcheck --force --enable=style . &> cppcheck.log

# Dependencies 

libvips has to have `gettext`, `glib2.0-dev` and `libxml2-dev`. Other
dependencies are optional, see below.

# Optional dependencies

If suitable versions are found, libvips will add support for the following
libraries automatically. See `./configure --help` for a set of flags to
control library detection. Packages are generally found with `pkg-config`,
so make sure that is working.

libtiff, giflib and libjpeg do not usually use `pkg-config` so libvips looks for
them in the default path and in `$prefix`. If you have installed your own
versions of these libraries in a different location, libvips will not see
them. Use switches to libvips configure like:

	./configure --prefix=/Users/john/vips \
		--with-giflib-includes=/opt/local/include \
		--with-giflib-libraries=/opt/local/lib \
		--with-tiff-includes=/opt/local/include \
		--with-tiff-libraries=/opt/local/lib \
		--with-jpeg-includes=/opt/local/include \
		--with-jpeg-libraries=/opt/local/lib

or perhaps:

	CFLAGS="-g -Wall -I/opt/local/include -L/opt/local/lib" \
		CXXFLAGS="-g -Wall -I/opt/local/include -L/opt/local/lib" \
		./configure --without-python --prefix=/Users/john/vips 

to get libvips to see your builds.

### vips8 Python binding

If `gobject-introspection`, `python-gi-dev`, and `libgirepository1.0-dev` are
available, libvips will install the vips8 Python binding. 

### libjpeg

The IJG JPEG library. Use the `-turbo` version if you can. 

### libexif

If available, libvips adds support for EXIF metadata in JPEG files.

### giflib

The standard gif loader. If this is not present, vips will try to load gifs
via imagemagick instead.

### librsvg

The usual SVG loader. If this is not present, vips will try to load SVGs
via imagemagick instead.

### libpoppler

The usual PDF loader. If this is not present, vips will try to load PDFs
via imagemagick instead.

### libgsf-1

If available, libvips adds support for creating image pyramids with `dzsave`. 

### libtiff

The TIFF library. It needs to be built with support for JPEG and
ZIP compression. 3.4b037 and later are known to be OK. 

### fftw3

If libvips finds this library, it uses it for fourier transforms. 

### lcms2, lcms

If present, `vips_icc_import()`, `vips_icc_export()` and `vips_icc_transform()`
are available for transforming images with ICC profiles. If `lcms2` is 
available it is used in preference to `lcms`, since it is faster.

### Large files

libvips uses the standard autoconf tests to work out how to support
large files (>2GB) on your system. Any reasonably recent unix should
be OK.

### libpng

If present, libvips can load and save png files. 

### ImageMagick, or optionally GraphicsMagick

If available, libvips adds support for loading all libMagick-supported
image file types. Use `--with-magickpackage=GraphicsMagick` to build against 
graphicsmagick instead.

Imagemagick 6.9+ needs to have been built with `--with-modules`. Most packaged
IMs are, I think, but if you are rolling your own, you'll need to pass
this flag to configure. 

If you are going to be using libvips with untrusted images, perhaps in a
web-server, for example, you should consider the security implications of
using a package with such a large attack surface. You might prefer not to
enable Magick support. 

### pangoft2

If available, libvips adds support for text rendering. You need the
package pangoft2 in `pkg-config --list-all`.

### orc-0.4

If available, vips will accelerate some operations with this run-time
compiler.

### matio

If available, vips can load images from Matlab save files.

### cfitsio

If available, vips can load FITS images.

### libwebp

If available, vips can load and save WebP images.

### OpenEXR

If available, libvips will directly read (but not write, sadly)
OpenEXR images.

### OpenSlide

If available, libvips can load OpenSlide-supported virtual slide
files: Aperio, Hamamatsu, Leica, MIRAX, Sakura, Trestle, and Ventana.

### swig, python, python-dev

If available, we build the vips7 python binding.

# Disclaimer

No guarantees of performance accompany this software, nor is any
responsibility assumed on the part of the authors. Please read the licence
agreement.