frame buffer
DirectFB
EZFB Linux Frame Buffer API
FreeBE/AF, cross platform driver for Allegro and MGL to enable accelerated features

linux kernel frame buffer docs (fbcon)
Linux 2.6.10 Documentation/fb
Linux framebuffer super mini howto

non-X low level graphics drivers
Linux Frame Buffer Driver Developers
The GGI Project, "Most applications that use SVGALib can be run on X or any other LibGGI backend by using a wrapper library which re-implements SVGALib (Section 3.12) using LibGGI."
KGI - Kernel Graphics Interface
SWindows

non-X Windowing Systems
The Nano-X Window System
Looking at Microwindows: Under the Hood of the Freepad
FBUI, or FrameBufferUI, is a small, in-kernel graphical user interface for Linux.
DinX
The KDrive Tiny X Server
TinyX
Integrated TinyX
Xynth Windowing System

non-X GUI libraries
OpenGUI
MiniGUI
PicoGUI
ozone gui
wGui : Dialog Manager Library
The GUI Toolkit, Framework Page
FLTK, Fast Light Toolkit
ParaGUI :: cross-platform widgetset

SDL
SDL, Simple DirectMedia Layer is a cross-platform multimedia library designed to provide low level access to audio, keyboard, mouse, joystick, 3D hardware via OpenGL, and 2D video framebuffer.
Verification Tools for SDL
Agar implements what we believe to be the most complete GUI toolkit for SDL/OpenGL®.
Kyra, is a simple, fully featured, industrial strength Sprite engine written in C++. It is built on top of SDL and has been tested on Windows and Linux. Kyra is licensed under the LGPL.
My SDL C++ Gui library
X-Oriented
Gtksdl Widget Homepage

Allegro
Allegro is a game programming library for C/C++ developers
Allegro Libraries
MASkinG - Miran Amon's Skinnable GUI Library
Mappy, Tile Map Library for Allegro
A library to mix OpenGL graphics with Allegro routines
FBlend, high speed allegro blender
Allegro Windowing
Adime, Allegro Dialogs Made Easy
CGUI, for Allegro
DEPUI, DEGFX and DETK, Portable gui, graphics and toolkit source code libraries under a GPL licence
Allegro Font Libraries
ALLEGTTF, Anti-aliased text output and font loading routines for Allegro
AllegroFont lib, is an Allegro wrapper for the wonderful FreeType2 library that makes Allegro (amongst other things) able to load and render TTF and many other famous font formats.
Allegro Tutorials
The Allegro GUI Clinic
Allegro Newbie Tutorial
Allegro 3D tutorial
Allegro Resources
Graphic libraries and source code examples, extensive list of mostly Allegro resources
Allegro.cc

SDL & Allegro
Guichan - A portable C++ GUI library designed for games using Allegro, SDL and/or OpenGL

X Oriented GUI Libraries
GLib Reference Manual
GTK
GtkFB: GTK+ for the Linux Framebuffer
PHP-GTK
french php-gtk page

GUI builder GUIs
glade
phpgladetool
gnope, Gnope is a program management environment, allowing you to download and deploy applications with a graphical user interface written in PHP-GTK2 on many platforms.
(wx)
wxPython
wxWidgets lets developers create applications for Win32, Mac OS X, GTK+, X11, Motif, WinCE, and more using one codebase. It can be used from languages such as C++, Python, Perl, and C#/.NET.
wxCode wxWindows resources
wxGlade
IDEs
SPE
wxDesigner, commercial
XRC
Python Card
Boa Constructor is a cross platform Python IDE and wxPython GUI Builder. Zope support.
Visualwx aims to be the ultimate RAD tool, designed for c++, python, perl, ruby lua and wxWidgets.
wxWorkshop, is a cross-platform IDE and RAD tool designed to aid and accelerate development of wxWidgets
Code Dragon, wxWindows IDE & RAD

2D
libart, GNOME/RaphLevien's advanced 2D graphics library (LGPLed)
DevIL, Developer's Image Library (DevIL) is a programmer's library to develop applications with very powerful image loading capabilities, yet is easy for a developer to learn and use.
g2 graphical library, 2D graphics library
GD Graphics Library, An ANSI C library for the dynamic creation of images. GD creates PNG, JPEG and GIF images, among other formats
ImageMagick
PHP ImageMagick
Anti-Grain Geometry, High Fidelity 2D Graphics
cairo is a vector graphics library designed to provide high-quality display and print output.
glitz is an OpenGL image compositing library.
2d Collision detection

Anti-aliasing algorithms
Fast Antialiasing, Dr. Dobb's Journal June 1992 v17 n6 p139(7)
Wu Algorithm
Antialiasing: Wu Algorithm
Xiaolin Wu's line algorithm, From Wikipedia, the free encyclopedia
Wu Anti-aliased Lines

Flash
development resources
The Labs Flash Page
Perl
Perl Flash, from The Labs
Specifications
A Concise Guide to the SWF File Format, from The Labs
Alexis' SWF Reference
Unix/Linux compilers & tools
Spalah Flash is a GTK2/GNOME2 based application for generating Macromedia SWF and W3C SVGanimations.
Swfdec, is a library for rendering Flash® animations and games.
SWFTOOLS is a collection of SWF manipulation and creation utilities
[Swftools-common] forum
swfc actionscript support
WikiSwftools
SSWF web page
Libswf v0.1
Ming, a SWF output library and PHP module
Flasm is a free command line assembler/disassembler of Flash ActionScript bytecode.
Flare is a free ActionScript decompiler. It decompiles SWFs produced by Macromedia Flash, including Flash MX 2004.
Macromedia Flash Player Download Center Linux
swfc examples
swftools examples
Les swftools
great, detail set of swfc compatible examples
Adobe Unix/Linux compilers & tools

Flash: 3D
Papervision
Sandy
swfz, based on Irrlicht
more actionscript repositories
Mostly Windows/Mac Tools
Actionscript Toolbox
Actionscripts.co.uk >> || , huge resource
about formequalsfunction draw methods

3D
The Mesa 3D Graphics Library
Direct Rendering Open Source Project, The Direct Rendering Infrastructure, also known as the DRI, is a framework for allowing direct access to graphics hardware under the X Window System in a safe and efficient manner.
OpenGL® ES is a royalty-free, cross-platform API for full-function 2D and 3D graphics on embedded systems - including consoles, phones, appliances and vehicles.
Crystal Space 3D is a free (LGPL) and portable 3D Game Development Kit written in C++.
OGRE represents the culmination of 4 years of continuous development, resulting in what is now regarded by many as the leading open source real time 3D rendering engine.
id Software: Technology Downloads
Quake Standards Group
The BUILD Engine, used by Duke Nukem 3D, Blood, Shadow Warrior...
CUBE, Landscape-style game engine that pretends to be an indoor first person shooter engine...
Power Render X
Irrlicht Engine, OpenGL, XML
Delta3D, Open source gaming & simulation
Alice
Yake, VR & Game Engine
Torque, Commercial
Engine Lists
DevMaster's Game and Graphics Engines Database
3D Engines List, list of 3D engines catagorized with descriptions
3D and Game Engines, from CYBER LOONIES: Your indispensable game programming site
Garage Games Engine List
more toolkit oriented
G3D the graphics3d C++ Library 6.02
Open Scene Graph, high peformance 3D graphics toolkit
Expression 3D Toolkit
Open Inventor, from SGI
The GNU 3DKit OpenGL
Mesa Home Page
GLUT
GLFW is a free, open source, portable framework for OpenGL application development.

particles
Open Dynamics Engine
also see: particle generation from 3D Modelling & Animation Links

nVidia
NVIDIA Cg Toolkit
NVIDIA GPU Programming Guide

Bindings
Perl
Simple DirectMedia Library Bindings for Perl
OpenGL, 0.5 - Perl module to display 3D data using OpenGL, GLU, GLUT, and GLX
Python
CGKit, 3D data processing
Python Imaging Library (PIL)
PyOpenGL 2.0, The Python OpenGL\xae Binding
Python-Allegro
PyMedia, is a Python module for wav, mp3, ogg, avi, divx, dvd, cdda etc files manipulations.

3D & Animation, more links

DVD Libraries & CSS
Gallery of CSS Descramblers, CMU CS Dept.
OpenDVD.org -DVD for every OS, This site is dedicated to raising awareness in regards to DVD playing on personal computers and the CSS protection scheme

Players
Videolan, courtesy of l'École de Paris
MPlayer, includes lots of skins
OpenQuickTime
mpeg video
SMPEG, SDL MPEG Player Library
Berkeley mpeg_play
MpegTV
ogle
Ogle
Googles DVD Player, frontend for ogle
oKle KDE DVD Player, frontend for ogle
Ogle IR, client for ogle
xine
xine
xine with css plug-in

SVCD
Authoring an SVCD with VCDImager
arson, CD ripper including VCS support
qvcd, a graphical frontend for GNU vcdimager and cdrdao

Codecs
Lists
fourcc, Video Codecs and Pixel Format Definitions
Codec-Download.com, list of Linux Codecs

MPEG
MPEG-2 Video Codec (with Source Code), from MPEG.ORG MPEG Software Simulation Group (MSSG)
XviD.org

Video Image Format Specifications
Ogg Theora, truely open source codec , "the video version of Ogg!"
V4L2 Video Image Format Specification, details on RGB (for typical PC graphics frame buffers) and YUV (for ITU-R601 and ITU-R656 digital video standards) formats
huffman-table
decode-lvc.c

APIs
v4l
video4linux HQ, video4linux is the original video capture/overlay API of the linux kernel
Video for Linux Two, overhauled v4l1 API
MP4Player internals

ajax video
AJAX, LAMP, and liveDVD for a Linux-based camera
GenReS plugin [includes] Perl script for embedding mplayer and mencoder in a browser and controlling it with Javascript.
ajax sprite video

TV Video Cards TV Card Viewers
Tv-cards.com
xawtv homepage
tvtime
Zapping
GnomeTV
KWintTV
dvr
MythTV
resources
ATI's Video 101 White Paper

Video Streamers
gstreamer
FFMPEG
MPEG4IP: Open Source, Open Standards, Open Streaming

Video Streaming Protocols
DVTS, DV Stream on IEEE1394 Encapsulated into IP

Video Streaming Docs & Programming
Choosing a video source
HOWTO: Streaming MPEG-4 with Linux, Linux Journal Article
Streaming Video Directly from TiVo, O'Reilly TIVO Hacks
Videolan Docs: Chapter 4. Stream a file

Mini-DV and Camera Drivers

Webcam Software
Camserv
setpwc, control settings for cameras supported by the pwc/x driver
also see Astronomy Links for webcam drivers

Non-Linear Digital Video
Editors
LiVES, - the Linux Video Editing System
OpenVIP, highly modular non-linear video editor and video processing library.
Kdenlive
Kino, non-linear DV editor
Avidemux, French site, available for Linux, FreeBSD, NetBSD...
veejay, for Linux, good looking interface
Cinelerra, for Linux, complete editing package
Jahshaka, Editing and effects. Includes OpenML (from SGI) support.
LVE, Linux Video Editor, includes a DVD authoring utilitiy
gAnim8, a full suite of tools for building and manipulating animated GIFs & small videos in a Gtk/Gnome environment
mjpeg tools

Cutters
mpgtx, GOP based mpeg editor
Cutter, cuts video
GOPchop

Video Special Effects Compositors
Film Gimp, has moved to CinePaint
CinePaint
GAnSO, Gnome Animation Studio
FreeJ, realtime effects and layering
The Comparametric Toolkit Page, High dynamic range image processing
Multi-Resolution Image Morphing

Format Converters
ppm2fli, generates .fli animation files from a series of ppms
...also see Kits & Bindings above

FAQs
comp.compression faq
MPEG-2 FAQ
comp.graphics.* FAQs
The Programmer's File Format Collection