Building QT

Warning: To build this, you need very beefy hardware. We are building this on a VM with 32 vCPUs and 128GB RAM. If you're trying to build it locally, you likely need to tweak MAKE_CORES to something lower, but you would still need a powerful workstation (32GB RAM minimum) to make this build.

Since our entire build environment resides inside a Docker container, you don't need to install any packages on the host system. Everything is confined to the Docker image. Do however note that as of this writing, the multi-platform support is still in beta so, you need to enable this. Instructions for how to get started with multi-platform builds can be found here.

$ cd webview
$ docker buildx build \
    --load \
    --build-arg GIT_HASH=$(git rev-parse --short HEAD) \
    -t qt-builder .

You should now be able to invoke a run executing the following command:

$ docker run --rm -t \
    -v ~/tmp/qt-src:/src:Z \
    -v ~/tmp/qt-build:/build:Z \
    -v $(pwd):/webview:ro \
    qt-builder

This will launch build-qt5.sh and start the process of building QT for all Raspberry Pi boards. The resulting files will be placed in ~/tmp/qt-build/.

You can learn more about this process in the blog post Compiling Qt with Docker multi-stage and multi-platform.

Build Arguments

You can append the following environment variables to configure the build process:

• CLEAN_BUILD: Set to 1 to ensure a clean build (not including the ccache cache).
• BUILD_WEBVIEW: Set to 0 to disable the build of ScreenlyWebView.
• TARGET: Specify a particular target (such as pi3 or pi4) instead of all existing boards.

Usage

DBus is used for communication. Webview registers screenly.webview object at /Screenly address on the session bus.

Webview provides 2 methods:loadPage and loadImage.

Example of interaction (python):

from pydbus import SessionBus

bus = SessionBus()
browser_bus = bus.get('screenly.webview', '/Screenly')

browser_bus.loadPage("www.example.com")

Supported protocols: http://, https://

Debugging

You can enable QT debugging by using the following:

export QT_LOGGING_RULES=qt.qpa.*=true