This file is a collection of informal notes, with references to where they were originally written. Each note should have a source and date mentioned. Let's keep these in date order, newest first. ----------------------------------------------------------------------- 2012-10-23; Pekka Paalanen http://lists.freedesktop.org/archives/wayland-devel/2012-October/005969.html For anyone wanting to port or write their own window manager to Wayland: Most likely you have a desktop window manager. A quick way to get started, is to fork Weston's desktop-shell plugin and start hacking it. Qt could be another good choice, but I am not familiar with it. You also need to understand some concepts. I'm repeating things I wrote to the wayland-devel list earlier, a little rephrased. We need to distinguish three different things here (towards Wayland clients): - compositors (servers) All Wayland compositors are indistinguishable by definition, since they are Wayland compositors. They only differ in the global interfaces they advertise, and for general purpose compositors, we should aim to support the same minimum set of globals everywhere. For instance, all desktop compositors should implement wl_shell. In X, this component corresponds to the X server with a built-in compositing manager. - shells This is a new concept compared to an X stack. A shell defines how a user and applications interact. The most familiar is a desktop (environment). If KDE, Gnome, and XFCE are desktop environments, they all fall under the *same* shell: the desktop shell. You can have applications in windows, several visible at the same time, you have keyboards and mice, etc. An example of something that is not a desktop shell could be a TV user interface. TV is profoundly different: usually no mouse, no keyboard, but you have a remote control with some buttons. Freely floating windows probably do not make sense. You may have picture-in-picture, but usually not several applications showing at once. Most importantly, trying to run desktop applications here does not work due to the incompatible application and user interface paradigms. On protocol level, a shell is the public shell interface(s), currently for desktop it is the wl_shell. - "window managers" The X Window Managers correspond to different wl_shell implementations, not different shells, since they pratically all deal with a desktop environment. You also want all desktop applications to work with all window managers, so you need to implement wl_shell anyway. I understand there could be special purpose X Window Managers, that would better correspond to their own shells. These window managers might not implement e.g. EWMH by the spec. When you implement your own window manager, you want to keep the public desktop shell interface (wl_shell). You can offer new public interfaces, too, but keep in mind, that someone needs to make applications use them. In Weston, a shell implementation has two parts: a weston plugin, and a special client. For desktop shell (wl_shell) these are src/shell.c and clients/desktop-shell.c. The is also a private protocol extension that these two can explicitly communicate with. The plugin does window management, and the client does most of user interaction: draw backgrounds, panels, buttons, lock screen dialog, basically everything that is on screen. -----------------------------------------------------------------------