Building the Overviewer from Source

These instructions are for building the C extension for Overviewer. Once you have finished with these instructions, head to Running the Overviewer.


Pre-built Windows and Debian executables are available on the Installing page. These kits already contain the compiled code and require no further setup, so you can skip to the next section of the docs: Running the Overviewer.

Get The Source

First step: download the platform-independent source! Either clone with Git (recommended if you know Git) or download the most recent snapshot

Once you have the source, see below for instructions on building for your system.

Build Instructions For Various Operating Systems

Windows Build Instructions

First, you’ll need a compiler. You can either use Visual Studio, or cygwin/mingw. The free Visual Studio Community is okay. You will need to select the “Desktop Development with C++” WORKLOAD. Microsoft has been changing up the names on this with the “Community” edition of Visual Studio. If nothing else works, just install every Individual Visual C++ component you can find :)


You will need the following:

  • Python 2.7

  • A copy of the Pillow sources.

  • The Pillow Extension for Python.

  • The Numpy Extension for Python.

  • The extensions can be installed via:

    c:\python27\python.exe -m pip -U numpy pillow

Building with Visual Studio

  1. Get the latest Overviewer source code as per above.

  2. From the Start menu, navigate to ‘Visual Studio 2017’ and open the ‘Developer Command Prompt for VS 2017’ (or whatever year) shortcut. A regular command or powershell prompt will NOT work for this.

  3. cd to the folder containing the Overviewer source code.

  4. Copy Imaging.h and ImPlatform.h from your Pillow sources into the current working directory.

  5. First try a build:

    c:\python27\python build

If you encounter the following errors:

error: Unable to find vcvarsall.bat

then try the following:

set MSSdk=1
c:\python27\python build

If the build was successful, there should be a c_overviewer.pyd file in your current working directory.

Building with mingw-w64 and msys2

This is the recommended way to build on Windows without MSVC.

  1. Install msys2 by following all the instructions on the msys2 installation page.

  2. Install the dependencies:

    pacman -S git mingw-w64-x86_64-python2-numpy mingw-w64-x86_64-python2-Pillow mingw-w64-x86_64-python2 mingw-w64-x86_64-toolchain
  3. Clone the Minecraft-Overviewer git repository:

    git clone

    The source code will be downloaded to your msys2 home directory, e.g. C:\msys2\home\Potato\Minecraft-Overviewer

  4. Close the msys2 shell. Instead, open the MinGW64 shell.

  5. Build the Overviewer by changing your current working directory into the source directory and executing the build script:

    cd Minecraft-Overviewer
    python2 build

After it finishes, you should now be able to execute from the MINGW64 shell.

Building with mingw

  1. Open a MinGW shell.

  2. cd to the Overviewer directory.

  3. Copy Imaging.h and ImPlatform.h from your Pillow sources into the current working directory.

  4. Build:

    python build --compiler=mingw32

If the build fails with complaints about -mno-cygwin, open the file Lib/distutils/ in an editor of your choice, and remove all mentions of -mno-cygwin. This is a bug in distutils, filed as Issue 12641.


You will need the gcc compiler and a working build environment. On Ubuntu and Debian, this can be done by installing the build-essential package.

You will need the following packages (at least):

  • python-imaging or python-pillow
  • python-imaging-dev or python-pillow-dev
  • python-dev
  • python-numpy

Then to build:

python2 build

At this point, you can run ./ from the current directory, so to run it you’ll have to be in this directory and run ./ or provide the the full path to Another option would be to add this directory to your $PATH. Note that there is a python2 install step that you can run which will install things into /usr/local/bin, but this is strongly not recommended as it might conflict with other installs of Overviewer.



You will need to have XCode and the XCode Command Line Tools installed (the Command Line Tools can be installed by going to the Downloads tab under the Xcode Preferences dialog).

  1. Download the source code for PIL from

  2. Compile the PIL code (python2 ./ build)

  3. Install PIL (sudo python2 ./ install)

  4. Find the path to the libImaging directory in the PIL source tree.

  5. Build Minecraft Overviewer with the path from step 4 as the value for PIL_INCLUDE_DIR:

    PIL_INCLUDE_DIR="path from step 4" python2 ./ build

The following script (copied into your MCO source directory) should handle everything for you:


# start with a clean place to work
python2 ./ clean

# get PIL
if [ ! -d "`pwd`/Imaging-1.1.7/libImaging" ]; then
    /usr/bin/curl -o imaging.tgz
    tar xzf imaging.tgz
    rm imaging.tgz

# build MCO
PIL_INCLUDE_DIR="`pwd`/Imaging-1.1.7/libImaging" python2 ./ build


FreeBSD is similar to OSX and Linux, but ensure you’re using Python 2.7. The port of Python 2.6 has bugs with threading under FreeBSD. Everything else you should need is ported, in particular math/py-numpy and graphics/py-imaging.

You may need or want to add the line:


to the file /etc/make.conf, but read the ports documentation to be sure of what this might do to other Python applications on your system.