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Spencer Smith
spencera@oregon.uoregon.edu
If you've been looking for a free graphics program with the capabilities of
Photoshop and the flexibility to run on a variety of platforms, The GIMP (http://www.gimp.org/)
could be for you.
The GIMP started out as the General Image Manipulation Program, an attempt
to give the Linux realm a program as flexible and extendable a graphics program
as Adobe Photoshop. The authors eventually decided to issue the program under
the GNU General Public License (GPL), and changed the name to the GNU Image
Manipulation Program. Different meaning, still The GIMP.
Because the program was reissued under the GNU license, the underlying code
was offered to the general public for examination and refinement (part of the
GNU license requires that the source code be available for change and refinement).
Although the GIMP was originally written for use under the X11 interface on
Unix, it has since been ported to Win32 code for Windows, and is in active development
as a MacOS X application. It currently runs under X11 on MacOS X.
This open-source model has allowed The GIMP to expand in capability, incorporating
functions and modules from a multitude of sources. The GIMP incorporates much
of the functionality of Adobe Photoshop, including layers, multiple levels of
undo, filters, multiple file formats, and a flexible scripting language for
automating multiple operations. I'd like to present a quick tour of The GIMP
and show some of the capabilities of this truly useful program.
The GIMP presents several floating palettes for its interface. Anyone who has Photoshop experience will be familiar with this use of multiple windows, although it can be confusing to the first time user (see illustration below).
Sample GIMP windows and palettes.
The GIMP palette is the main window for the program, where all the tools and
file menus are accessed. (All of these menus can also be accessed from a drop-down
menu, by right-clicking on the image you're working with.) All the standard
selection tools are present, as well as Text tools, Gradient and Pattern tools,
Painting tools (such as Airbrush, Paintbrush, Pencil, etc.), and more esoteric
tools like the Dodge/Burn tool, Paths, Sharpen, and Smudge.
Double-clicking on a tool will bring up the Tool Options palette, such as the
settings for the Paintbrush tool shown in the top center menu in the illustration
above. This palette will change, depending on the active tool at the time. There
are any number of settings, which will modify the way the tool interacts with
your image.
The Layers, Channels & Paths palette show the different layers you have
created for your image. Several different options for the look and feel of an
image can be stored in separate layers, then imposed and combined to create
very different effects.
The GIMP offers more filters than I can mention, and more third-party extensions
are available every day. Some of the standard filters available are Emboss,
Lens Flare, Unsharp Mask, Gaussian Blur, Clouds, and a host of other filters.
Other features include an Image Map dialog for creating active image regions
for web pages and a Fractal Explorer module for integrating fractal patterns
and regions into your imagesÑthe options are endless.
In addition to the pre-compiled filters, a flexible scripting language, Script-Fu,
is included with the program. Script-Fu is based on Scheme, a functional programming
language from the Lisp family of languages. It offers a very powerful recursion
structure, strong typing of variables, and a large database of predefined functions
and procedures.
The GIMP can save your finished image in most of the more popular file formats
for Web development and page layout. JPEG, TIFF, Sun Raster, and Postscript
are available. The GIF image format is not available by default due to some
copyright and patent issues, but the emerging PNG standard is supported. Depending
on the color scheme or your image, you can convert between any of the supported
image formats.
The GIMP may not be the best tool for your graphic needs, nor the easiest or most flexible tool to use. However, it has a clearly superior price/performance ratio, and given its low, low price ( free!), I think it's well worth a try.
