Installation on Ubuntu 21.04


i was trying to install Klayout in Ubuntu 21.04, I faced quite some problem in installing it using the .deb file in the download section of the file.
This is do to some missing dependencies that have been removed in the public repositories ? in particular the Qt5 and the libpython3.8 .
I managed to solve the problem installing manually the Qt5 dependencies and I was left with the libpython3.8 that I have no idea of how to solve since the library is already installed but is the 3.9 version that comes as default with the distro.

I then proceeded to manually compile the files, even there i faced quite few dependencies problems coming from some qtxml ... library.

The final solution was to install the software using a simple " sudo apt install klayout".
The software got installed but at the running moment a warning was displayed regarding a Wayland related problem and the software didn't run.
I then logout and log in using gnome on xorg.
Now the software works fine, but I have to use the xorg environment.

Did someone experience similar issues with the installation ? hope my description can help someone with the same problem. Would be also interesting to know what is missing in the new ubuntu that causes so much trouble


  • I would like to see, somewhere in the release collateral,
    a complete list of all packages required (with version)
    or better yet, some "pull scripts" that would ensure that
    the dependencies are all in place or make it so. Like
    apt for Ubuntu, rpm for RHEL, ??? Rather than waiting
    for compile-fail and wading through the barf, why not
    get in front of it?

    Some of these distributions are too fast-revving to
    rely on, and some users (like me) are not really good
    at compiling if anything anomalous happens. Such
    as some distro-monger deciding you should be on a
    different version, without asking.

  • Hi Jim,

    To be frank, I'm trying to avoid the odd Ubuntu versions. They did not turn out to be stable in the past. I'm focussing on the even LTS versions (16, 18, 20, 22 ...).

    KLayout does not have too many dependencies fortunately. But it's always difficult to figure out the actual package names required.

    On Ubuntu 20 these are the packages I need to install:

      apt-get install -y \
          gcc \
          g++ \
          make \
          libz-dev \
          qt5-default \
          qttools5-dev \
          libqt5xmlpatterns5-dev \
          qtmultimedia5-dev \
          libqt5multimediawidgets5 \
          libqt5svg5-dev \
          ruby \
          ruby-dev \
          python3 \

    I just tried with the Ubuntu 21.10 Docker image and at least the build started with the following packages:

    apt-get install -y qt5ct qt5-qmake gcc g++ make libz-dev libqt5xmlpatterns5-dev qtmultimedia5-dev libqt5multimediawidgets5 libqt5svg5-dev ruby ruby-dev python3 python3-dev
    ./ -without-qtbinding -j4 -prefix /usr/bin/klayout

    I don't know if qt5ct is the right way to do it, but I was not able to find anything useful otherwise. The "-without-qtbinding" trick is to speed up the build process - unless you need Qt5 in your scripts, you can skip the Qt5 binding with this option. This also reduces the dependencies.

    The -prefix is arbitrary and indicates the installation location. "" will finally install klayout there. I can do this on Docker as I'm root there.

    At the time I'm writing this, the build is still running :)

    Best regards,


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