Linux Appliance Design

11.3. Graphics Libraries

Using the Linux framebuffer interface, we have reduced the problem of manipulating pixels on the display to the problem of writing bytes to memory. But think of some of the ways in which we would like to manipulate display pixels: drawing lines of a specified thickness, drawing windows with rounded edges and a three-dimensional look, transferring images, or drawing text with a given font and size. These are nontrivial problems; that's why we need a graphics library. With an appropriate graphics library, we can write programs that manipulate lines, windows, images, and text, and let the underlying library decide what to do with the pixels.

The most common library for manipulating graphics objects in Linux is Xlib. Xlib is ...