frameless-qt-poc

FramelessWindow Demo for Qt Applications (POC)

Why this exists?

Since Qt 5.15 there are two new QWindow slots (functions):

• startSystemMove
• startSystemResize

These functions can be used to implement frameless windows ( using the Qt::FramelessWindowHint window flag ) that can be moved and resized like normal windows having a frame and a title bar, but the application is totally free to draw those elements. This is called Client Side Window Decorations (CSD). There is a similar QML based demo and also a blog post by Johan Helsing.

This POC is not design oriented, but on functionality and simplicity. There are several other similar demos with much more elaborated design, and based on native functions which may be of interest for older Qt versions, for instance:

• GoodWindow
• qt-csd

This is an easier way, and has the advantage of working on Windows, macOS and Linux (both X11/xcb and Wayland). It can be used with projects based on Qt 5.15 and Qt 6.x.

Results

Tests built with Qt 5.15.2 and Qt 6.3.0

✅ means that it is usable.

❌ means that it is not usable.

❓ means that the results are not conclusive.

Platform:	Qt5 + move window	Qt5 + resize	Qt6 + move window	Qt6 + resize
Windows	✅	✅	✅	✅
macOS	✅	❌	✅	✅
Linux X11/xcb	✅	✅	✅	✅
Linux Wayland	✅	✅	✅	✅

Other Projects using the FramelessWindow class

• Drumstick MIDI File Player
• GenPassword
• TimeOut