# Building from source

If you are a developer and you want to build from source, follow these steps.

## Requirements

pikepdf requires:

- a C++20 compliant compiler

- pybind11

- libqpdf 12.2.0 or higher from the qpdf project.

On Linux the library and headers for libqpdf must be installed because pikepdf compiles code against it and links to it.

Check Repology for qpdf to see if a recent version of qpdf is available for your platform. Otherwise you must build qpdf from source. (Consider using the binary wheels, which bundle the required version of libqpdf.)

Note

pikepdf should be built with the same compiler and linker as libqpdf; to be precise both must use the same C++ ABI. On some platforms, setup.py may not pick the correct compiler so one may need to set environment variables `CC` and `CXX` to redirect it. If the wrong compiler is selected, `import pikepdf._core` will throw an `ImportError` about a missing symbol.

## GCC or Clang, linking to system libraries

To link to system libraries (the ones installed by your package manager, such `apt`, `brew` or `dnf`:

- Clone the pikepdf repository

- Install libjpeg, zlib and libqpdf on your platform, including headers

- If desired, activate a virtual environment

- Run `pip install .`

## GCC or Clang and linking to user libraries

pikepdf’s setup.py will check the following locations, in the order given here, for qpdf’s headers and libraries (both of which are required for a build):

1. the paths specified by environment variables `QPDF_SOURCE_TREE` and `QPDF_BUILD_LIBDIR`

2. a folder named `qpdf` that is installed parallel to `pikepdf`, e.g. if pikepdf is located in `$HOME/src/pikepdf`, then we check `$HOME/src/qpdf` for qpdf

3. the system default’s location for these resources

If you wish to link pikepdf against a different version of the qpdf (say, because pikepdf requires a newer version than your operating system has), then you might do something like:

- Install the development headers for libjpeg and zlib (e.g. `apt install libjpeg-dev`)

- Build qpdf from source and run `cmake --install` to install it to `/usr/local`

- Clone the pikepdf repository

- From the pikepdf directory, run

  >     env CXXFLAGS=-I/usr/local/include/libqpdf LDFLAGS=-L/usr/local/lib  \
  >         pip install .

### On Windows (requires Visual Studio 2015)

pikepdf requires a C++20 compliant compiler. See our continuous integration build script in `.appveyor.yml` for detailed and current instructions. Or use the wheels which save this pain.

These instructions require the precompiled binary `qpdf.dll`. See the qpdf documentation if you also need to build this DLL from source. Both should be built with the same compiler. You may not mix and match MinGW and Visual C++ for example.

Running a regular `pip install` command will detect the version of the compiler used to build Python and attempt to build the extension with it. We must force the use of Visual Studio 2015.

- Clone this repository.

- In a command prompt, run:

  >     %VS140COMNTOOLS%\..\..\VC\vcvarsall.bat" x64
  >     set DISTUTILS_USE_SDK=1
  >     set MSSdk=1

- Download qpdf-12.2.0-bin-msvc64.zip from the qpdf releases page.

- Extract `bin\*.dll` (all the DLLs, both qpdf’s and the Microsoft Visual C++ Runtime library) from the zip file above, and copy it to the `src/pikepdf` folder in the repository.

- Run `pip install .` in the root directory of the repository.

Note

The user compiling `pikepdf` to must have registry editing rights on the machine to be able to run the `vcvarsall.bat` script.

## Building against a qpdf source tree

Follow these steps to build pikepdf against a different version of qpdf, rather than the one provided with your operating system. This may be useful if you need a more recent version of qpdf than your operating system package manager provides, and you do not want to use Python wheels.

    # Build libqpdf from source
    cd $QPDF_SOURCE_TREE
    cmake -S . -B build -DCMAKE_BUILD_TYPE=RelWithDebInfo -DBUILD_SHARED_LIBS=ON
    cmake --build build --parallel --target libqpdf
    QPDF_BUILD_LIBDIR=$PWD/build/libqpdf

    # Create a fresh virtual environment
    cd $PIKEPDF_SOURCE_TREE
    python3 -m venv .venv
    source .venv/bin/activate

    # Build pikepdf from source
    env QPDF_SOURCE_TREE=$QPDF_SOURCE_TREE QPDF_BUILD_LIBDIR=$QPDF_BUILD_LIBDIR \
        pip install -e .

Note that the Python wheels for pikepdf currently compile their own version of qpdf and several of its dependencies to ensure the wheels have the latest version. You can also refer to the GitHub Actions YAML files for build steps.

## Building against a qpdf source tree

Using Visual Studio C++:

- `winget install git.git`

- `winget install python.python.3.12`

- `winget install Microsoft.VisualStudio.2022.BuildTools`

- `winget install kitware.cmake`

Download qpdf external libs and unpack in place.

    wget https://github.com/qpdf/external-libs/releases/download/release-$version/qpdf-external-libs-bin.zip -Outfile libs.zip
    expand-archive -path libs.zip -destinationpath .

Download qpdf and build from source using:

    cd $qpdf
    cmake -S . -B build
    cmake --build build --config Release

Switch to pikepdf source folder. Set up environment variables and get pip to build/install:

    cd $pikepdf
    $env:INCLUDE = "$qpdf\include"
    $env:LIB = "$qpdf\build\libqpdf\Release\"
    cp $LIB\libqpdfXX.dll src\pikepdf  # Help Python loader find libqpdf.dll
    python -m venv .venv
    .venv\scripts\activate
    pip install -e .

## Building the documentation

Documentation is generated using Sphinx and you are currently reading it. To regenerate it:

    pip install pikepdf[docs]
    cd docs
    make html