GrafX2 is a bitmap program based on Amiga Deluxe Paint and Brilliance specializing in 256 color painting with a mouse. The first version was released in 1996 by Sunset Design studio and it continued being developed and released until 2001 when development was abandoned . In 2007 the code was found again by a user named PulkoMandy and development re-started until present day. It is primarily a Haiku, Linux and Windows software although it has been ported on other platforms as well.
Ranked in these QuestionsQuestion Ranking
Pro Free, open source, and cross-platform
GrafX2 is totally free to use, copy, and modify. It's available on Windows, Linux, Mac OS X, Haiku, AROS, MorphOS, SkyOS, Syllable, Mint, and a few more systems. Basically anything is supported by the SDL library.
Pro Very large number of tools and effects
Pro Supports tileset addition and extraction
Pro Scriptable using Lua
GrafX2 is scriptable using the Lua language, which can be used to automate tasks and add new functionality to it. The script library features advanced color reduction and enhancement tools, palette analysis, and much more.
Pro Supports animations
The program has a basic support for animation using frames in newer versions. Graphics can be cloned and copied between frames and changed slightly.
See here how to animate with GrapfX2 https://www.youtube.com/watch?v=Gnq6zBZOqoM
Pro Supports many file formats
GrafX2 supports many file formats, including the popular gif and png, but also importing and exporting from deluxe paint, degas elite, and various other editors using custom formats.
Pro Has a great palette tool
You can create gradients from one color to another, work in either RGB or HSL color space, save and load palettes, sort and organize palettes, and even work on "color cycling" images.
Pro Has a customizable UI with themes support
Theme UI style can easily be changed from settings including buttons and colors.
Pro Palette Color Cycling
GraphX2 being based on older 256 bitmap software has inherited some tricks that modern pixel editors do not have . One of them being the ability to cycle color palette and produce animations and effects with it.