framebuffer

A framebuffer is a region of memory that holds a digital image intended for display. Each pixel on the screen corresponds to a stored color value in the framebuffer, and the display controller reads this memory to refresh the visible image. Framebuffers can reside in system RAM or in dedicated video memory, and they are used by graphics hardware or software renderers to present graphics output.

Layout and formats commonly describe how pixels are stored. Most framebuffers are linear, with a fixed or pitched stride describing the number of bytes per scanline. Pixel formats specify color depth and arrangement, such as 24-bit RGB, 32-bit RGBA, or 16-bit formats like RGB565. Some systems support paletted modes or separate depth/stencil buffers for 3D rendering. The choice of format affects memory bandwidth and color fidelity.

Buffering and compositing are central to modern displays. A front buffer contains the image currently shown on screen, while one or more back buffers are drawn to off-screen. Double buffering reduces tearing by swapping buffers during vertical blanking. Triple buffering and page flipping further smooth updates, at the cost of additional memory.

Implementation and usage vary by platform. In many systems, the framebuffer resides in GPU memory and is managed by graphics drivers. In embedded and some desktop systems, a Linux framebuffer device (such as /dev/fb0) provides a raw memory interface. On contemporary desktops, a display server or compositor often renders into surfaces that are later presented to the framebuffer through a compositor-managed pipeline.

Overall, the framebuffer is a fundamental abstraction for displaying images, serving as the bridge between software rendering and the digital display. Its size, format, and buffering strategy influence performance, latency, and visual quality.