Nicolas Caramelli

DirectFB2 is a fork of DirectFB, a graphics library designed with embedded systems in mind that was widely used in the GNU/Linux embedded world. DirectFB2 comes with changes such as a Meson build system, a pure C implementation and a modularization of the source code.

Access to the low-level display is based on a DRM/KMS system module (or possibly on a legacy Framebuffer system module), and depending on the platform, hardware-accelerated graphics rendering can be achieved using the architecture of the GFX driver modules.

The core library is very light (no external dependencies) and provides basic font/image/video rendering support which can be demonstrated with the DirectFB-examples.

The use of additional DirectFB providers based on external libraries is also possible thanks to the DirectFB-media package, such as rendering fonts with the FreeType library, rendering images with libpng or jpeg libraries, rendering videos with FFmpeg or GStreamer libraries.

For 3D graphics, OpenGL or Vulkan rendering can be done with the DirectFB graphics backend. As an example, the Mesa 3D implementation makes OpenGL rendering possible with a DirectFBGL module or with EGL for the DirectFB platform, and the SwiftShader implementation makes Vulkan rendering possible with the DirectFB WSI.

This talk aims at getting started with DirectFB2 which may be worth considering on some devices.

Although KMS/DRM can replace the Linux Framebuffer, there are a number of programs and libraries that can be built on top of the Linux Framebuffer (without X11 or Wayland dependencies) and that might still be worth considering. The Linux Framebuffer allows direct access to pixels: we will illustrate it with various rendering tools (Fbpad, Fbi, NetSurf, MPlayer, ...), but also with drawing libraries such as Cairo or Evas, and multimedia frameworks like FFmpeg or GStreamer. The Mesa 3D project makes OpenGL rendering possible using only the Linux Framebuffer with GLFBDev or EGL: mesa-demos and yagears programs will be shown. We will then cover graphics libraries (GLUT, SDL, EFL, GTK, Qt) that allow to integrate high level applications running directly on top of the Linux Framebuffer with no compositor. An example will be described using either WebKitGTK or QtWebKit for the rendering of a HTML5 media player and a WebGL sample, using the Linux Framebuffer port of those libraries and toolkits. This talk is inspired by the HiGFXback project which aims at preserving historical backends used for graphics on GNU/Linux systems.