Running X11 applications under Wayland
Source: vignatti.wordpress.com Intel developer Tiago Vignatti has posted a new blog entry detailing the current state of development work aimed at enabling X11 native applications to run on systems with the X.Org replacement Wayland. His posting describes the xwayland framework, which the Weston reference compositor for Wayland can use to run X11 applications. As soon as an X11 application connects to it, xwayland starts an X Server in the background; this application, and any other applications started subsequently, then communicates with the X Server.
The X Server does not communicate directly with the graphics hardware, but instead contains an xwayland backend and an xwayland graphics driver which communicates with xwayland in Weston. A window manager in Weston's xwayland adds decoration (borders, title bar) to the image data supplied over the communications pathway and outputs the image. This path is also used, for example, to tell X11 applications when a user selects text.
Xwayland components output images in exactly the same way as applications written for Wayland – there are no protocol calls or other major tasks, so that total overhead is close to zero when outputting images. Drag and drop support in xwayland is still being worked on. All of the basic functionality for passing user input to X11 applications is now complete, but work on improving this functionality is ongoing.
This process allows applications programmed with Motif/Xt or older versions of GTK+ and Qt to run on Weston. Other Wayland compositors are likely to take inspiration from the code and mode of operation. This is not necessary for GNOME, KDE Software Collection or other modern programs, however, as current (developer) versions of graphics libraries such as GTK+ and Qt already include code for passing images directly to Wayland compositors such as Weston.
- Wayland - Beyond X, a feature from The H.