Linux Appliance Design

Chapter 11. DESIGNING A FRAMEBUFFER INTERFACE

If you decide to add a graphical user interface (GUI) to your appliance, you will be faced with the following challenge. On one hand, your appliance's graphics hardware is controlled by low-level commands that manipulate video memory. On the other hand, your users don't want to manipulate video memory; they want to manipulate high-level objects like menus and buttons. In order to build the kind of interface your users want, you will use a set of software layers known collectively as the graphics stack.

The graphics stack, as used for the Laddie appliance, is illustrated in Figure 11-1. The Linux framebuffer device driver provides a low-level but uniform interface to the graphics hardware's video memory. ...