Twobjects quick reference

Twobjects is the result of migration taiwins from libweston, as libweston has many constrains, lacks of important features and has several severe bugs for daily users. Firstly I looked into wlroots and found it was not modular enough and the design did not fit the taiwins, inspired by the two prior project, I created this library for faciliting the development of the wayland compositor.

Features

• twobjects implements all the interfaces in the wayland.xml and several important protocols such as xdg-shell and linux-dmabuf.

• twobjects is designed to backend agnositc, you can stack it on top of other backend implementation such as wlroots.

• twobjects is designed to be autonomous. Unlike wlroots approach, which heavily exposes wl_signal from protocols so the users still has to write a layer of glue to use them. In twobjects, many of wayland protocols manages itself thus transparent to the backend developer. A good example is wl_data_device.

• twobjects has built-in logging and profiling system and other utilites.

Building

Install dependencies:

• meson

• wayland

• wayland-protocols

• xkbcommon

• libdrm

• pixman

Commands for build:

meson build
ninja -C build

Commands for install:

sudo ninja -C build install

Getting started

Many protocols essentially implements a wl_global object like wl_compositor in the compositor, twobjects typically implements a corresponding type like tw_compositor. You can create the static global by using function like tw_compositor_create_global or allocate the memory yourself then use tw_compositor_init.

There are some cases where twobjects abstracts several protocols into common interface for users. For example, the tw_desktop_manager implements both wl_shell and xdg_shell and exposes tw_desktop_surface for the user, this is similar to the design of libweston.

For “middle-man” protocols like wl_data_device, the internals or managing wl_data_source, wl_data_offer is transparent to user. Users simply initialize the tw_data_manager for getting the clipboard in wayland.

Twobjects utilities

Twobjects implements utilies like matrix, cursor, logging and profiling functions for users. Check out the headers for usage.