The Puzzle library is designed to quickly find visually similar images
(GIF, PNG, JPG), even if they have been resized, recompressed, recolored
or slightly modified.
The library is free, lightweight yet very fast, configurable, easy to use
and it has been designed with security in mind.
libwmf is a library for Unix like machines that can convert wmf
files into other formats, currently it supports a gd binding
to convert to png, and an X one to draw direct to an X window
or pixmap.
VIPS's a free image processing system. It aims to be about half way between
Excel and Photoshop. It's obviously much smaller than these two, but it's
not a toy either (about 200k lines of code). It's very bad at photo
retouching, but it's great (much better than programs like Photoshop, I
think) at all the other things you use photoshop for. It's particularly
good with large images (ie. images larger than the amount of RAM in your
machine), and for working with colour.
3D Scientific Data Visualization and Plotting
The Mayavi project includes two related packages for 3-dimensional
visualization:
Mayavi: A tool for easy and interactive visualization of data, with
seamless integration with Python scientific libraries.
TVTK: A Traits-based wrapper for the Visualization Toolkit, a popular
open-source visualization library.
These libraries operate at different levels of abstraction. TVTK
manipulates visualization objects, while Mayavi lets you operate
on your data, and then see the results. Most users either use the
Mayavi user interface or program to its scripting interface; you
probably don't need to interact with TVTK unless you want to create
a new Mayavi module.
llpp is a graphical PDF viewer which aims to superficially resemble
less(1).
Telak is a small tool to draw local or remote pictures on your root window.
This is very useful if you want to have RRD graphs drawn above your wallpaper.
a2png is a UNIX program that converts plain text into PNG images.
AA-lib is a low-level graphics library similar to many other libraries
except for the fact that AA-lib does not require a graphics device! In
fact, no "graphical" output is possible. AA-lib uses a modern, high-tech
ascii-art renderer in place of outmoded and cumbersome graphical output.
The AA-lib API is designed to be similar to that of other graphics
libraries so learning its API should be simple.
Auto Adjust Photo is a tiny command-line image manipulation tool for
automatic color correction of photos. It tries to make the picture look
better. The program does this by analyzing the input image and then sets
the most optimal contrast, gamma, color balance and saturation for it.
This program generates images from mathematical functions, draws them on the
SVGAlib screen, and cycles the palette. The images are intended to have a
hypnotic effect.
After exiting the program, you must switch consoles before the display will be
usable again.