Building libmypaint

Documentation > Contributor Guides > Building

MyPaint’s brush engine, libmypaint is a discrete external library to MyPaint.

When building a branch/tag of MyPaint, build the corresponding branch of libmypaint.

e.g. MyPaint/main with libmypaint/main
When building old commits of MyPaint, search for libmypaint using git log, then infer the corresponding libmypaint commit by cross-referencing the commit logs.

Dependencies

All configurations and builds:
- json-c (>= 0.11)
- C compiler, make etc.
Most configurations (all except --disable-introspection --without-glib):
- GObject-Introspection
- GLib
When building from git (developer package names vary by distribution):
For --enable-gegl (GIMP does not require this):
- GEGL + BABL

Debian-based

# apt install -y build-essential
# apt install -y libjson-c-dev libgirepository1.0-dev libglib2.0-dev

When building from git:

# apt install -y python autotools-dev intltool gettext libtool

Red Hat-based

# yum install -y gcc gobject-introspection-devel json-c-devel glib2-devel

When building from git:

# yum install -y git python autoconf intltool gettext libtool

SUSE-based

# zypper install -t pattern devel_basis
# zypper install gcc13 gobject-introspection-devel libjson-c-devel glib2-devel

When building from git:

# zypper install git python311 autoconf intltool gettext-tools libtool

Build libmypaint

Optimization Flags

MyPaint and libmypaint benefit dramatically from autovectorization and other compiler optimizations. You may want to set your CFLAGS before compiling:

export CFLAGS='-Ofast -ftree-vectorize -fopt-info-vec-optimized -march=native -mtune=native -funsafe-math-optimizations -funsafe-loop-optimizations'

To avoid potential glitches, make sure to compile both libmypaint and MyPaint using the same optimization flags.

Steps

The traditional setup works just fine.

$ ./autogen.sh    # Only needed when building from git.
$ ./configure
# make install
# ldconfig

Maintainer mode

We don’t ship a configure script in our git repository. If you’re building from git, you have to kickstart the build environment with:

$ git clone https://github.com/mypaint/libmypaint.git
$ cd libmypaint
$ ./autogen.sh

This script generates configure from configure.ac, after running a few checks to make sure your build environment is broadly OK. It also regenerates certain important generated headers if they need it.

Folks building from a release tarball don’t need to do this: they will have a configure script from the start.

Configure

$ ./configure
$ ./configure --prefix=/tmp/junk/example

There are several MyPaint-specific options. These can be shown by running

$ ./configure --help

Action	Command
Build	`$ make`
Test (run unit tests)	`$ make check`
Install	`# make install`
Uninstall	`# make uninstall`

Check Availability

Make sure that pkg-config can see libmypaint before trying to build with it.

$ pkg-config --list-all | grep -i mypaint

If it’s not found, you’ll need to add the relevant pkgconfig directory to the pkg-config search path. For example, on CentOS, with a default install:

# sh -c "echo 'PKG_CONFIG_PATH=/usr/local/lib/pkgconfig' >>/etc/environment"

Make sure ldconfig can see libmypaint as well

# ldconfig -p |grep -i libmypaint

If it’s not found, you’ll need to add the relevant lib directory to the LD_LIBRARY_PATH:

$ export LD_LIBRARY_PATH=/usr/local/lib
# sh -c "echo 'LD_LIBRARY_PATH=/usr/local/lib' >>/etc/environment

Alternatively, you may want to enable /usr/local for libraries. Arch and Redhat derivatives:

# sh -c "echo '/usr/local/lib' > /etc/ld.so.conf.d/usrlocal.conf"
# ldconfig

Make Release

The distribution release can be generated with:

$ make dist

And it should be checked before public release with:

$ make distcheck

Localisation

Contribute translations here: https://hosted.weblate.org/engage/mypaint/.

The list of languages is maintained in po/LINGUAS. Currently this file lists all the languages we have translations for. It can be regenerated with:

$ ls po/*.po | sed 's$^.*po/\([^.]*\).po$\1$' | sort > po/LINGUAS

You can also disable languages by removing them from the list if needed.

A list of files where localizable strings can be found is maintained in po/POTFILES.in.

Strings update

You can update the .po files when translated strings in the code change using:

$ cd po && make update-po

When the results of this are pushed, Weblate translators will see the new strings immediately.