- Linux framebuffer
The Linux framebuffer (fbdev) is a graphic hardware-independent
abstraction layer to show graphics on a console without relying on system-specific libraries such asSVGALib or the heavyoverhead of theX Window System .It was originally implemented to allow the
Linux kernel to emulate a text console on systems such as theApple Macintosh that do not have a text-mode display, and was later expanded to Linux's originally-supportedIBM PC compatible platform, where it became popular largely for the ability to show theTux logo on boot up. More significantly, it serves as a way of displayingUnicode characters on the Linux console. Under the non-framebuffer, VGA display of the PC, comprehensive Unicode support was impossible, for VGA console fonts were limited to 512 characters.Nowadays several Linux programs such as
MPlayer , and libraries such asGGI , SDL,GTK+ andQtopia can use the framebuffer immediately, avoiding the overhead of anX server . This is particularly popular inembedded system s.The Linux framebuffer has long suffered from its poor performance, but there is now a library
DirectFB which provides a framework for hardware acceleration.FBUI (FrameBuffer UI) provides in-kernel windowing system (GUI) for the framebuffer subsystem at very low cost: the entire subsystem is about 50 kilobytes in size. It permits multiple programs to share the framebuffer simultaneously; it permits overlapping moveable windows; each program may have multiple windows; and it allows windows on every virtual console. Included with FBUI is libfbui which provides abstractions for windows, events, etc., as well as quite a few sample programs such as load monitor, clock, calculator, scribble pad, image viewer, window managers, and a simple MPEG2 player. FBUI includes an optimized code for the VESA framebuffer driver.See also
*
Framebuffer External links
*Sourceforge [http://sourceforge.net/projects/linux-fbdev/ Project Page]
* [http://tldp.org/HOWTO/Framebuffer-HOWTO.html Framebuffer HOWTO]
* [http://www.xfree86.org/4.3.0/fbdev.4.html XFree86 doc]
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