Building ART on Windows

These instructions reproduce, step by step, what the official windows.yml GitHub Actions workflow does to produce the Windows installer (and portable .7z) releases published on the releases page. The build uses MSYS2 and is meant to be run from an MSYS2 shell, not a plain Windows terminal.

Supported variants

Variant	Runner	MSYS2 subsystem	Compiler	Notes
x64	windows-latest	UCRT64	gcc
arm64	windows-11-arm	CLANGARM64	clang	Requires SIMDE and extra warning-suppression flags

1. Install MSYS2

Download and install MSYS2 from https://www.msys2.org/ (the CI installs it to C:\msys2, so that path is assumed below — adjust it if you install elsewhere). Update it and open the shell that matches your target variant:

• x64 → the UCRT64 shell (C:\msys2\msys2_shell.cmd -ucrt64)
• arm64 → the CLANGARM64 shell (C:\msys2\msys2_shell.cmd -clangarm64)

All the commands below are run inside that MSYS2 shell.

Install the base tools:

pacman -Syu   # you may need to re-open the shell if pacman restarts itself
pacman -S git wget xz p7zip

2. Install prebuilt ART dependencies

ART publishes a prebuilt MSYS2 package repository (artraweditor/msys2-repo) containing pinned versions of several dependencies that are faster to grab than to build. Register it as a local pacman repository:

# UCRT64 (x64):
export ART_MSYS2_REPO=ucrt64
export ART_PKG_PREFIX=mingw-w64-ucrt-x86_64
export ART_MSYS2_REPO_VER=1.0.1
export ART_COMPILER=gcc
# CLANGARM64 (arm64), use instead:
# export ART_MSYS2_REPO=clangarm64
# export ART_PKG_PREFIX=mingw-w64-clang-aarch64
# export ART_MSYS2_REPO_VER=1.0
# export ART_COMPILER=clang

wget https://github.com/artraweditor/msys2-repo/releases/download/${ART_MSYS2_REPO_VER}/repo-${ART_MSYS2_REPO}.tar
tar xf repo-${ART_MSYS2_REPO}.tar

cat >> /etc/pacman.conf <<EOF
[custom-${ART_MSYS2_REPO}]
SigLevel = Optional TrustAll
Server = file://$(pwd)/repo-${ART_MSYS2_REPO}
EOF

pacman -Sy
for p in ${ART_COMPILER} cmake autotools ninja gtkmm3 lcms2 fftw lensfun mimalloc opencolorio; do
    pacman --noconfirm -S custom-${ART_MSYS2_REPO}/${ART_PKG_PREFIX}-${p}
done

This installs the compiler toolchain, CMake, Ninja, GTKmm3, LCMS2, FFTW, Lensfun, mimalloc and OpenColorIO in one step.

3. Remaining dependencies, built from source

Exiv2 0.27.7

wget https://github.com/Exiv2/exiv2/releases/download/v0.27.7/exiv2-0.27.7-Source.tar.gz
tar xzf exiv2-0.27.7-Source.tar.gz
mkdir build-exiv2 && cd build-exiv2
cmake \
  -GNinja \
  -DCMAKE_BUILD_TYPE=Release \
  -DCMAKE_INSTALL_PREFIX=c:/msys2/usr/local \
  -DEXIV2_ENABLE_WIN_UNICODE=1 \
  -DEXIV2_ENABLE_BMFF=1 \
  ../exiv2-0.27.7-Source
ninja install
cd ..

LibRaw (latest master)

git clone --depth 1 https://github.com/LibRaw/LibRaw.git
cd LibRaw
autoreconf -i
# gcc for UCRT64, clang for CLANGARM64:
export CC=gcc CXX=g++
# export CC=clang CXX=clang++

CPPFLAGS=-DUSE_X3FTOOLS ./configure --prefix=c:/msys2/usr/local
make -j
make install
cd ..

CTL (ACES CTL interpreter, latest master)

git clone --depth 1 https://github.com/ampas/CTL.git
mkdir build-CTL && cd build-CTL
cmake \
  -GNinja \
  -DCMAKE_BUILD_TYPE=Release \
  -DCMAKE_INSTALL_PREFIX=c:/msys2/usr/local \
  -DCMAKE_CXX_FLAGS="-fpermissive -fms-extensions" \
  -DCTL_BUILD_TESTS=0 -DCTL_BUILD_TOOLS=0 \
  ../CTL
ninja install
cd ..

SIMDE 0.8.2 — arm64 (CLANGARM64) only

wget https://github.com/mesonbuild/meson/releases/download/1.10.0/meson-1.10.0.tar.gz
tar xzf meson-1.10.0.tar.gz
wget https://github.com/simd-everywhere/simde/archive/refs/tags/v0.8.2.tar.gz
tar xzf v0.8.2.tar.gz
cd simde-0.8.2
python ../meson-1.10.0/meson.py setup build -Dbuildtype=release -Dtests=false -Dprefix=c:/msys2/usr/local
python ../meson-1.10.0/meson.py install -C build
cd ..

4. Configure and build ART

git clone https://github.com/artraweditor/ART.git
mkdir build && cd build
export PKG_CONFIG_PATH=c:/msys2/usr/local/lib/pkgconfig

# UCRT64 (x64):
ART_CXX_FLAGS=
ART_SIMDE=0
# CLANGARM64 (arm64), use instead:
# ART_CXX_FLAGS="-Wno-ignored-attributes -Wno-unused-command-line-argument"
# ART_SIMDE=1

cmake \
  -GNinja \
  -DCMAKE_BUILD_TYPE=Release \
  -DENABLE_LIBRAW=1 \
  -DENABLE_OCIO=1 \
  -DENABLE_CTL=1 \
  -DCTL_INCLUDE_DIR=/usr/local/include/CTL \
  -DCMAKE_LIBRARY_PATH=/usr/local/lib \
  -DBUILD_BUNDLE=1 \
  -DENABLE_SIMDE=${ART_SIMDE} \
  -DCMAKE_CXX_FLAGS="${ART_CXX_FLAGS}" \
  ../ART

ninja install

This installs a self-contained bundle under build/Release.

Update the Lensfun camera/lens database:

lensfun-update-data

5. Packaging: portable bundle, installer

Collect the DLLs and produce a portable, self-contained folder using ART’s own bundling script:

cd build/Release
python ../../ART/tools/win/bundle_ART.py -o ../../bundle -v -E -I -m c:/msys2
cd ../..

To build the Windows installer, Inno Setup is required. From a regular Windows shell (PowerShell), with Chocolatey available:

choco install innosetup
cd bundle
iscc /F"installer" "WindowsInnoSetup.iss"

This produces installer.exe; rename it, e.g. ART_<version>_Win64.exe (or ..._Windows_arm64.exe for the arm64 build).

Optionally, also archive the bundle folder itself as a portable, no-install-required .7z package:

mv bundle ART_portable
7z a ART_portable.7z ART_portable

Reference

This document is derived from the CI definition in .github/workflows/windows.yml. Refer to that file for the exact, up-to-date, authoritative build recipe — these instructions may lag behind future CI changes.