DisplayCAL Python 3 Project

This project intended to modernize the DisplayCAL code including Python 3 support.

Florian Höch, the original developer, did an incredible job of creating and maintaining DisplayCAL for all these years. But, it seems that, during the pandemic, very understandably, he lost his passion to the project. Now, it is time for us, the DisplayCAL community, to contribute back to this great tool.

This project is based on the HEAD of the Sourceforge version, which had 5 extra commits that Florian has created after the 3.8.9.3 release on 14 Jan 2020.

Status Update (18 May 2022)

DisplayCAL is in PyPI now (yay!).

Here is a screenshots showing the tool working with Python 3.10:

Currently, DisplayCAL is working with Python 3.8 to 3.11 and wxPython 4.1.1 to 4.2.1.

Here is a list of things that is working:

• The UI and general functionality.
• Calibration + Characterization (Profiling).
• Installing the created ICC profile both locally and system-wide (requires root permissions).
• Profile Info window is now fully working (on some systems we still have an issue related to default values #67).
• Measurement report creation.
• Creating, displaying and uploading Colorimeter Corrections.
• Measuring and reporting display uniformity.
• Creating charts with Test Chart Editor and creating diagnostic 3d data.
• Creating 3D LUTs.
• Creating synthetic ICC profiles.
• and a lot of other stuff are working properly.

What is not working

• Everything should be working now. But, incase you encounter any bugs please create issues.

How to install

Currently, there is no RPM, DEB, APP or MSI packages. These are coming soon.

To test the code you can either run it directly from the source or install it as a sdist package. To do this:

Prerequisites:

• Assorted C/C++ builder tools
• dbus
• glib 2.0 or glibc
• gtk-3
• libXxf86vm
• pkg-config
• python3-devel

Please install these from your package manager.

# Brew on MacOS
brew install glib gtk+3 python@3.10

# Debian installs
apt-get install build-essential dbus libglib2.0-dev pkg-config libgtk-3-dev libxxf86vm-dev

# Fedora core installs
dnf install gcc glibc-devel dbus pkgconf gtk3-devel libXxf86vm-devel python3-devel

Note, if your system's default python is outside the supported range you will need to install a supported version and its related devel package.

Then pull the source:

git clone https://github.com/eoyilmaz/displaycal-py3
cd ./displaycal-py3/

At this stage you may want to switch to the develop branch to test some new features or possibly fixed issues over the main branch.

git checkout develop

Then you can build and install DisplayCAL using:

make build
make install

The build step assumes your system has a python3 binary available that is within the correct range. If your system python3 is not supported and you installed a new one, you can try passing it to the build command. eg

$ python3 --version
# Python 3.12.2
make build # this will fail
$ python3.11 --version
# Python 3.11.8
make SYSTEM_PYTHON=python3.11 build # should work

If this errors out for you, you can follow the Manual Setup section below.

Otherwise, this should install DisplayCAL. To run the UI:

make launch

Manually Setup

If the makefile workflow doesn't work for you, you can setup the virtual environment manually. Ensure the python binary you're using is supported:

python -m venv .venv # python3.11 -m venv .venv if system python is not a supported version
source .venv/bin/activate  # Windows: .venv\Scripts\activate.bat
pip install -r requirements.txt
python -m build
pip install dist/DisplayCAL-3.9.*.whl

This should install DisplayCAL. To run the UI:

displaycal

Road Map

Here are some ideas on where to focus the future development effort:

• Add DisplayCAL to PyPI (#83). (Done! Display PyPI Page)
• Replace the DisplayCAL.ordereddict.OrderedDict with the pure Python dict which is ordered after Python 3.6. (Done!)
• Make the code fully compliant with PEP8 with the modification of hard wrapping the code at 88 characters instead of 80 characters. This also means a lot of class and method/function names will be changed. Thanks to black and some flake8 this is mostly done.
• Remove the RealDisplaySizeMM C-Extension which is just for creating a 100 x 100 mm dialog and getting EDID information. It should be possible to cover all the same functionality of this extension and stay purely in Python. It is super hard to debug and super hard to maintain.
• Try to move the UI to Qt. This is a big ticket. The motivation behind this is that it is a better library and more developer understands it and the current DisplayCAL developers have more experience with it.
• Create unit tests with Pytest and reach to ~100% code coverage. The 3.8.9.3 version of DisplayCAL is around 120k lines of Python code (other languages are not included) and there are no tests (or the repository this project has adapted didn't contain any tests). This is a nightmare and super hard to maintain. This is an ongoing work, with the latest commits we have around 200 tests (which is super low, should be thousands) and the code coverage is around 26% (again this is super low, should be over 99%).
• Replace the wexpect.py with the latest release of Pexpect. There is no comment in the code on why we have a wexpect.py instead of using the PyPI version of Pexpect. Update: we believe it is because Pexpect doesn't support Windows. Then it is a good idea to port the DisplayCAL implementation to the Pexpect project.
• Replace os.path related code with pathlib.Path class.
• Organize the module structure, move UI related stuff in to ui module etc., move data files into their own folders.
• Use importlib_resources module for reading data files.
• Update the Remaining time calculation during profiling to estimate the time by also considering the luminance of the remaining patches to have a better estimation. Because, patches with higher luminance values are measured quickly than patches with lower luminance values.

Issues related to these ideas have been created. If you have a feature request, you can create more issues or share your comment on the already created issues or create merge requests that are fixing little or big things.

Because there are very little automated tests, the code need to be tested constantly. Please help us with that.

Have fun!