Building QtWebEngine for Qt 5.15

QtWebEngine is a very large and complicated Qt module as it contains the Chrome browser engine. It takes a lot of space, memory and time to build and therefore it is highly recommended to be built separately from rest of Qt.
It can be built natively on the Raspberry Pi but you do need one of the more powerful models with plenty of memory. With the 4GB or 8GB Raspberry Pi 4 or 5 models it is fully possible to build, but you might still need to enable swap and also limit the amount of parallel builds the ninja build tool (that qtwebengine uses internally for building) is allowed to use.

Start by first building the base Qt 5.15 and make sure it works, then you can continue to build the qtwebengine module. The examples below will be using Qt version 5.15.16 (See release notes here) so if you are using any other version, just adjust the paths to correspond to the version of Qt that you are using.

Note: These example builds of QtWebEngine 5.15 has been done in 32-bit Raspberry Pi OS only. Building on the 64-bit variant has not been tested yet.

Note: Qt 5.15 series is rather old already and is soon End-Of-Life, consider using Qt 6 series.

Download the sources for QtWebEngine

You have two choices here, either download the the release archives or use qtwebengine from git.

The archives are easier and take less space but unfortunately getting old. Git repositories takes up more space and needs a bit more work.

a) Download release archive

Download the QtWebEngine source that corresponds to the version of Qt you are using and have previously built

wget https://download.qt.io/official_releases/qt/5.15/5.15.16/submodules/qtwebengine-everywhere-opensource-src-5.15.16.tar.xz

b) Use git repository

git clone https://invent.kde.org/qt/qt/qtwebengine.git
git checkout -t remotes/origin/5.15.16
git submodule update --init

Install required and any optional build dependencies

Setup sources for building

Extract the source archive and create a separate build directory.

Disable jumbo build in 5.15

Note: This is not needed if building on Bullseye

We had no luck with the default jumbo build system in 5.15, compiling failed with obscure errors that made no sense, so we need to disable it.

Adjust the parameter with help of sed with the command (adjust paths if you need to) or use your favorite editor to change the option:

sed -i -e 's|use_jumbo_build=true|use_jumbo_build=false|' ../qtwebengine-everywhere-src-5.15.16/src/buildtools/config/common.pri

Configure QtWebEngine for building

/opt/Qt/5.15.16/bin/qmake ../qtwebengine-everywhere-src-5.15.16 -- -no-webengine-geolocation

If all goes well, you should be presented with a summary that looks similar to this (Yours does not need to match 100% as it depends on what packages you have installed and on any options given):

• Example configuration summary for QtWebEngine 5.15.7

All is well as long as the configuration does not give errors. Just make sure that any extra features you might need are found and enabled.

Compiling QtWebEngine 5

Now if everything is properly detected (and no mention about QtWebEngine not being built), proceed to building.

Start the build

We must limit the amount of parallel builds, especially on anything less than 8GB, by limiting ninja parallel builds with NINJAJOBS to 4 or less. On 4GB you need to go down to 2 jobs.

Invoke make with:

make -j4 NINJAJOBS=-j4

Building will take a very long time.

Install QtWebEngine

When (and if) the build is complete, the installation part is easy, just:

make install

And you are done. Now you should be able to use QtWebEngine in your Qt and QtQuick applications.

Possible build issues with QtWebEngine and their solutions

The following table has collected some of the problems and build issues found with QtWebEngine

internal compiler error: in convert_move, at expr.c:218
 static void exec_ops(const Op* ops, const void** args,

#pragma GCC optimize ("O0")

qtwebengine-everywhere-src-5.15.2/src/3rdparty/chromium/ui/gl/gl_bindings_autogen_egl.h:201:5:
error: ‘EGLDeviceEXT’ has not been declared

Out of memory: Killed process 125689 (cc1plus)