FreeRDP Qt platform plugin

Application details

This is a Qt5/Qt6 platform plugin to export application through RDP without modifying the original code.

Requirements

• Qt5 development librairies (>= 5.12.8)
• libfreerdp (>= 2.100.20230321)

Set up dev environment

export INSTALL_PATH=/your/preferred/install/path
export PKG_CONFIG_PATH=${INSTALL_PATH}/usr/lib/pkgconfig:${INSTALL_PATH}/usr/lib/x86_64-linux-gnu/pkgconfig
export LD_LIBRARY_PATH=${INSTALL_PATH}/usr/lib/

Install requirements (for Ubuntu 22.04)

system libraries

apt install qtbase5-private-dev libxkbcommon-dev libglib2.0-dev libxrender-dev libudev-dev libfontconfig1-dev libfreetype6-dev libxcursor-dev qttools5-dev-tools

Installation

Configuration

Have a look inside meson_options.txt to see what options you might want to change while configuring the project, and then:

meson setup build -Dprefix=${INSTALL_PATH}/usr -Dglobal_install=false

Compilation

ninja -C build install

Using

To use the platform plugin you need to specify the path where QT can find plugins:

export QT_PLUGIN_PATH=${INSTALL_PATH}/usr/lib/

Now launch any Qt5 program (you'll find many in the examples directory of Qt) with the -platform freerdp parameter, for example:

./menus -platform freerdp

You can also provide options to the freerdp platform:

./menus -platform freerdp:port=3389:address=127.0.0.1

Platform parameters list

Parameter	Example	Default	Description
address	address=127.0.0.1	0.0.0.0	Bind (listen) IP address for the RDP server
port	port=3392	3389	Listening port for the RDP server
socket	socket=43	None	Fixed socket
width	width=1024	800	Initial screen width, in pixels
height	height=768	600	Initial screen height, in pixels
cert	cert=/path/to/cert.pem	cert.pem	Path to TLS certificate
key	key=/path/to/key.key	cert.key	Path to TLS key
secrets	secrets=/path/to/ssl_secrets	None	Path to secrets file
fg-color	fg-color=#ebbdb2	white	Foreground color for window decorations, accepts hex-formatted colors and colors from https://doc.qt.io/qt-5/qcolor.html#setNamedColor
bg-color	bg-color=#282828	black	Background color for window decorations, accepts hex-formatted colors and colors from https://doc.qt.io/qt-5/qcolor.html#setNamedColor
font	font=Oswald	time	Font name for window titles
fps	fps=60	24	Target internal rendering framerate
mode	mode=optimize	autodetect	Display modes. Values: legacy|autodetect|optimize
noegfx	noegfx	egfx enabled	Flag to disable egfx rendering
noclipboard	noclipboard	clipboard enabled	Flag to disable clipboard channel
norootwindow	norootwindow	windowId 1 is root window	By default the first created window has a special role and is never decorated, this option allow to disable this behaviour
qtwebengineKbdCompat	qtwebengineKbdCompat	Client layout dependent Qt key events	Flag to force qfreerdp to always emit Qt key events as if generated by a Qwerty (us) layout so that qtWebEngine can generate correct key.code events.

Testing

To run qfreerdp's unit tests:

meson test -C builddir

Qt WebEngine

If you want to use qfreerdp in front of a Qt WebEngine application, keep in mind that its keyboard support is subpar, especially for layouts different than US qwerty. In particular, KeyEvent.code for javascript will be deduced with the assumption that QKeyEvents were sent using a US qwerty layout[0] if you are not using one of the few mainstream platforms (xcb, wayland, windows, cocoa).

In order to try to somewhat improve the state of things for qfreerdp, we make available two workarounds:

• First, qfreerdp has the option masquerade as xcb, as in that case Qt WebEngine actually handles QKeyEvents' nativeScanCode and nativeModifiers correctly. Simply use -platform freerdp_xcb instead of the usual freerdp
• The qtwebengineKbdCompat platform option, that will convert all Qt::Key events sent as if they were generated by a qwerty layout, so that the reverse operation done by Qt WebEngine is actually correct. However this approach has a few caveats:
  • AltGr isn't supported until Qt6.7
  • The IntlBackslash key, present on ISO layouts but not ANSI layouts, isn't supported.

Those two workarounds suffer from the same additional limitations:

• No support for NumLock until https://bugreports.qt.io/browse/QTBUG-134107 is fixed
• Dead keys take one more keypress to take effect.

[0] - https://github.com/qt/qtwebengine/blob/6.8.2/src/core/web_event_factory.cpp#L1701