--- icon: material/image-sync-outline --- # Image processing Some of the [built-in plugins] depend on external libraries for efficient image processing, most notably the [social] plugin to generate [social cards], and the [optimize] plugin for applying [image optimization]. This guide explains how to install those libraries in different environments. [built-in plugins]: ../index.md [social]: ../social.md [social cards]: ../../setup/setting-up-social-cards.md [optimize]: ../optimize.md [image optimization]: ../../setup/building-an-optimized-site.md ## Dependencies The libraries for image processing are entirely optional, and only need to be installed if you want to use the [social] plugin or the [optimize] plugin. The libraries are listed under the `imaging` extra: ``` pip install "mkdocs-material[imaging]" ``` This will install compatible versions of the following packages: - [Pillow] - [CairoSVG] [Pillow]: https://pillow.readthedocs.io/ [CairoSVG]: https://cairosvg.org/ ### Cairo Graphics [Cairo Graphics] is a graphics library and dependency of [Pillow], which Material for MkDocs makes use of for generating [social cards] and performing [image optimization]. See the following section which explains how to install [Cairo Graphics] and its dependencies on your system: === ":material-apple: macOS" Make sure [Homebrew] is installed, which is a modern package manager for macOS. Next, use the following command to install all necessary dependencies: ``` brew install cairo freetype libffi libjpeg libpng zlib ``` === ":fontawesome-brands-windows: Windows" As stated in the [installation guide], the easiest way to get up and running with the [Cairo Graphics] library on Windows is by installing [GTK+]. You can also download a precompiled [GTK runtime]. === ":material-linux: Linux" There are several package managers for Linux with varying availability per distribution. The [installation guide] explains how to install the [Cairo Graphics] library for your distribution: === ":material-ubuntu: Ubuntu" ``` apt-get install libcairo2-dev libfreetype6-dev libffi-dev libjpeg-dev libpng-dev libz-dev ``` === ":material-fedora: Fedora" ``` yum install cairo-devel freetype-devel libffi-devel libjpeg-devel libpng-devel zlib-devel ``` === ":fontawesome-brands-suse: openSUSE" ``` zypper install cairo-devel freetype-devel libffi-devel libjpeg-devel libpng-devel zlib-devel ``` The following environments come with a preinstalled version of [Cairo Graphics]: - [x] No installation needed in [Docker image] - [x] No installation needed in [GitHub Actions] (Ubuntu) [Cairo Graphics]: https://www.cairographics.org/ [Homebrew]: https://brew.sh/ [installation guide]: https://www.cairographics.org/download/ [GTK+]: https://www.gtk.org/docs/installations/windows/ [GTK runtime]: https://github.com/tschoonj/GTK-for-Windows-Runtime-Environment-Installer/releases [Docker image]: https://hub.docker.com/r/squidfunk/mkdocs-material/ [GitHub Actions]: ../../publishing-your-site.md#with-github-actions ### pngquant [pngquant] is an excellent library for lossy PNG compression, and a direct dependency of the [built-in optimize plugin]. See the following section which explains how to install [pngquant] system: === ":material-apple: macOS" Make sure [Homebrew] is installed, which is a modern package manager for macOS. Next, use the following command to install all necessary dependencies: ``` brew install pngquant ``` === ":fontawesome-brands-windows: Windows" Installing [pngquant] on Windows is a little more involved. The [pngquant-winbuild] repository contains a guide on how to set up an environment for building [pngquant] on Windows. === ":material-linux: Linux" All popular Linux distributions, regardless of package manager, should allow to install [pngquant] with the bundled package manager. For example, on Ubuntu, [pngquant] can be installed with: ``` apt-get install pngquant ``` The same is true for `yum` and `zypper`. The following environments come with a preinstalled version of [pngquant]: - [x] No installation needed in [Docker image] [pngquant]: https://pngquant.org/ [built-in optimize plugin]: ../../plugins/optimize.md [pngquant-winbuild]: https://github.com/jibsen/pngquant-winbuild ## Troubleshooting ### Cairo library was not found After following the installation guide above it may happen that you still get the following error: ```bash no library called "cairo-2" was found no library called "cairo" was found no library called "libcairo-2" was found cannot load library 'libcairo.so.2': error 0x7e. Additionally, ctypes.util.find_library() did not manage to locate a library called 'libcairo.so.2' cannot load library 'libcairo.2.dylib': error 0x7e. Additionally, ctypes.util.find_library() did not manage to locate a library called 'libcairo.2.dylib' cannot load library 'libcairo-2.dll': error 0x7e. Additionally, ctypes.util.find_library() did not manage to locate a library called 'libcairo-2.dll' ``` This means that the [`cairosvg`][PyPi CairoSVG] package was installed, but the underlying [`cairocffi`][PyPi CairoCFFI] dependency couldn't [find][cffi-dopen] the installed library. Depending on the operating system the library lookup process is different: !!! tip Before proceeding remember to fully restart any open Terminal windows, and their parent hosts like IDEs to reload any environmental variables, which were altered during the installation process. This might be the quick fix. === ":material-apple: macOS" On macOS the library lookup checks inside paths defined in [dyld][osx-dyld]. Additionally each library `name` is checked in [three variants][find-library-macOS] with the `libname.dylib`, `name.dylib` and `name.framework/name` format. [Homebrew] should set every needed variable to point at the installed library directory, but if that didn't happen, you can use the debug script below to see what paths are looked up. A [known workaround][cffi-issue] is to add the Homebrew lib path directly before running MkDocs: ```bash export DYLD_FALLBACK_LIBRARY_PATH=/opt/homebrew/lib ``` View source code of [cairo-lookup-macos.py] ```bash title="Python Debug macOS Script" curl "https://raw.githubusercontent.com/squidfunk/mkdocs-material/master/includes/debug/cairo-lookup-macos.py" | python - ``` === ":fontawesome-brands-windows: Windows" On Windows the library lookup checks inside the paths defined in the environmental `PATH` variable. Additionally each library `name` is checked in [two variants][find-library-Windows] with the `name` and `name.dll` format. The default installation path of [GTK runtime] is: ```powershell C:\Program Files\GTK3-Runtime Win64 ``` and the libraries are in the `\lib` directory. Use the debug script below to check if the path is included. If it isn't then: 1. Press ++windows+r++. 2. Run the `SystemPropertiesAdvanced` applet. 3. Select "Environmental Variables" at the bottom. 4. Add the whole path to the `lib` directory to your `Path` variable. 5. Click OK on all open windows to apply changes. 6. Fully restart any open Terminal windows and their parent hosts like IDEs. ```powershell title="You can also list paths using PowerShell" $env:Path -split ';' ``` View source code of [cairo-lookup-windows.py] ```powershell title="PowerShell - Python Debug Windows Script" (Invoke-WebRequest "https://raw.githubusercontent.com/squidfunk/mkdocs-material/master/includes/debug/cairo-lookup-windows.py").Content | python - ``` === ":material-linux: Linux" On Linux the library lookup can [differ greatly][find-library-Linux] and is dependant from the installed distribution. For tested Ubuntu and Manjaro systems Python runs shell commands to check which libraries are available in [`ldconfig`][ubuntu-ldconfig], in the [`gcc`][ubuntu-gcc]/`cc` compiler, and in [`ld`][ubuntu-ld]. You can extend the `LD_LIBRARY_PATH` environmental variable with an absolute path to a library directory containing `libcairo.so` etc. Run this directly before MkDocs: ```bash export LD_LIBRARY_PATH=/absolute/path/to/lib:$LD_LIBRARY_PATH ``` You can also modify the `/etc/ld.so.conf` file. The Python script below shows, which function is being run to find installed libraries. You can check the source to find out what specific commands are executed on your system during library lookup. View source code of [cairo-lookup-linux.py] ```bash title="Python Debug Linux Script" curl "https://raw.githubusercontent.com/squidfunk/mkdocs-material/master/includes/debug/cairo-lookup-linux.py" | python - ``` [PyPi CairoSVG]: https://pypi.org/project/CairoSVG [PyPi CairoCFFI]: https://pypi.org/project/CairoCFFI [osx-dyld]: https://www.unix.com/man-page/osx/1/dyld/ [ubuntu-ldconfig]: https://manpages.ubuntu.com/manpages/focal/en/man8/ldconfig.8.html [ubuntu-ld]: https://manpages.ubuntu.com/manpages/xenial/man1/ld.1.html [ubuntu-gcc]: https://manpages.ubuntu.com/manpages/trusty/man1/gcc.1.html [cffi-issue]: https://github.com/squidfunk/mkdocs-material/issues/5121 [cffi-dopen]: https://github.com/Kozea/cairocffi/blob/f1984d644bbc462ef0ec33b97782cf05733d7b53/cairocffi/__init__.py#L24-L49 [find-library-macOS]: https://github.com/python/cpython/blob/4d58a1d8fb27048c11bcbda3da1bebf78f979335/Lib/ctypes/util.py#L70-L81 [find-library-Windows]: https://github.com/python/cpython/blob/4d58a1d8fb27048c11bcbda3da1bebf78f979335/Lib/ctypes/util.py#L59-L67 [find-library-Linux]: https://github.com/python/cpython/blob/4d58a1d8fb27048c11bcbda3da1bebf78f979335/Lib/ctypes/util.py#L92 [cairo-lookup-macos.py]: https://raw.githubusercontent.com/squidfunk/mkdocs-material/master/includes/debug/cairo-lookup-macos.py [cairo-lookup-windows.py]: https://raw.githubusercontent.com/squidfunk/mkdocs-material/master/includes/debug/cairo-lookup-windows.py [cairo-lookup-linux.py]: https://raw.githubusercontent.com/squidfunk/mkdocs-material/master/includes/debug/cairo-lookup-linux.py