GIMP

GIMP

Screenshot of GIMP 2.6
Developer(s)	The GIMP Development Team
Initial release	January 1996
Development status	Active
Written in	C and GTK+
Operating system	Linux, Mac OS X, Microsoft Windows, FreeBSD, Solaris
Available in	Multilingual,[1] 52 languages in GIMP 2.6, 37 fully translated, others partly translated.[2]
Type	Raster graphics editor
License	GNU General Public License
Website	www.gimp.org

GIMP (short for the GNU Image Manipulation Program) is a free software raster graphics editor. It is primarily employed as an image retouching and editing tool.^[3] In addition to free-form drawing, GIMP can accomplish essential image work-flow steps such as resizing, editing, and cropping photos, combining multiple images, and converting between different image formats. GIMP can also be used to create basic animated images in the GIF format. At present, GIMP is usable for amateur or professional work with images intended for viewing on monitors and printing on ink-jet printers.

The product vision for GIMP is to become a high-end graphics application for the editing and creation of original images, icons, graphical elements of web pages and art for user interface elements. One point in GIMP's product vision would see GIMP used for the development of cutting-edge image-processing algorithms.^[4]

History

Screenshot of GIMP 2.6 manipulating an image

GIMP originally stood for the General Image Manipulation Program.^[5] GIMP's original creators, Spencer Kimball and Peter Mattis, began developing GIMP in 1995 as a semester-long project at the University of California, Berkeley. The first public release of GIMP (0.54) was made in January 1996.^[6][7] In 1997 GIMP became a part of the GNU Project, and the acronym GIMP was changed to the GNU Image Manipulation Program.^[8] Currently GIMP is maintained and enhanced by a group of volunteers under the auspices of the GNOME Project.^[9][10] GIMP was originally created for UNIX systems; Linux, SGI IRIX and HP-UX were supported in the first release.^[5][11] Since the first release GIMP was rapidly adopted and a community emerged consisting of users who created tutorials, artwork and shared techniques.^[12] Since the initial release, GIMP has been ported to many operating systems including Microsoft Windows and Mac OS X; the original port to the win32 platform was started by Finnish programmer Tor Lillqvist (tml) in 1997 and was supported in the GIMP 1.1 release.^[11]

GIMP has used three graphical user interface (GUI) toolkits since its inception; GIMP originally used Motif on the first public release (0.54). At some point Peter Mattis became disenchanted with Motif and developed his own GUI toolkit named the GIMP toolkit (GTK); GTK had successfully replaced Motif in the 0.60 release of GIMP.^[7][13] Finally GTK was re-written to be object oriented and was renamed GTK+; this was first visible in GIMP 0.99.

User interface

GIMP has a main window and several dialogue windows used for tools, color palettes and so forth; as such GIMP uses a (controlled) single document interface. In a single document interface the responsibility of managing additional windows is left to the operating system. This windowing format has been criticised and where some attention to the user interface is being debated.^[14] Because GIMP uses multiple windows a given user must place each window in a functional location, other user concerns for windowing include a situation where the toolbox and layer windows end up hidden behind unrelated application windows. This occurs less often in recent versions, where GIMP tells desktop environments how to handle its windows.

In order to construct its interface GIMP uses the GIMP tool kit (GTK+). GTK+ was designed to replace Motif, a proprietary toolkit upon which GIMP depended. Originally GTK+ was a part of the GIMP source tree, but has since been made into a standalone library. While originally being designed to run on Unix-like operating systems, GIMP and GTK+ have been ported to Microsoft Windows, Mac OS X, and other operating systems.

GIMP usability team

GIMP contributors signed up to join the OpenUsability project.^[15] Since then a dedicated usability team has been established to guide the future of the GIMP interface. A user interface brainstorming group was created for GIMP,^[16][17] where users of GIMP can send in their suggestions as to how they think the GIMP user interface could be improved.

Single window GIMP

At Libre Graphics Meeting 2008 Peter Sikking gave a presentation outlining future plans for GIMP to have a single window interface,^[18] amongst many other changes. The use of single window mode will be optional.

Media attention

As a popular application, GIMP is regularly reviewed. The reviews often examine the fitness of GIMP for use in professional environments; as such GIMP is often cited as a replacement for Adobe Photoshop.^[19][20] Even though comparisons to Photoshop are of regular occurrence, the maintainers of GIMP state that GIMP does not aim to replicate Photoshop.^[21]

GIMP 2.6 has been reviewed twice by Ars Technica. In the first review, Ryan Paul noted that GIMP provides "Photoshop-like capabilities and offers a broad feature set that has made it popular with amateur artists and open source fans. Although GIMP is generally not regarded as a sufficient replacement for high-end commercial tools, it is beginning to gain some acceptance in the pro market."^[19] While previously it had been recognized that GIMP had extensive capabilities, few reviewers have cited GIMP as a tool used in professional environments. Dave Girard also reviewed GIMP 2.6, specifically with the aim of testing GIMP's fitness for professional tasks. He noted at the beginning that GIMP was a high-end tool, but the review conclusion noted that although many of GIMP's tools were of high quality, he felt that it lacked in some areas such as non-destructive editing, tools such as a saturation brush and that GIMP did not integrate well to Mac OS X; Dave Girard recognized however that OS X is not the native platform of GIMP.^[22][23]

Features

Brushes dialogue in GNOME

Tools used to manipulate images can be accessed via the toolbox, through menus and dialogue windows. They include filters and brushes, as well as transformation, selection, layer and masking tools.

• Color: GIMP has several ways of selecting colors including palettes, color choosers and using an eyedropper tool to select a color on the canvas. The built in color choosers include RGB/HSV selector or scales, water-color selector, CMYK (cyan, magenta, yellow, key (black)) selector and a color-wheel selector. Colors can also be selected using hexadecimal color codes as used in HTML color selection. GIMP has native support for indexed color and RGB color spaces, other color spaces are supported using decomposition where each channel of the new color space becomes a black and white image. CMYK, LAB and HSV (hue, saturation, value) are supported this way.^[24][25] Color blending can be achieved using the blend tool, by applying a gradient to the surface of an image and using GIMP's color modes. Gradients are also integrated into tools such as the brush tool, when the user paints this way the output color slowly changes. There are a number of default gradients included with GIMP, a user can also create custom gradients with tools provided.

• Selections and paths: in GIMP there are several tools that can be used to create selections including a rectangular and circular selection tool, free select tool, and fuzzy select tool (also known as magic wand). More advanced selection tools include the select by color tool for selecting contiguous regions of color and the scissors select tool which creates selections semi-automatically between areas of highly contrasting colors. GIMP also supports a quick mask mode where a user can use a brush to paint the area of a selection, visibly this looks like a red colored overlay being added or removed. The foreground select tool is an implementation of Simple Interactive Object Extraction (SIOX) a method used to perform the extraction of foreground elements, such as a person or a tree in focus. The Paths Tool allows a user to create vectors (also known as Bézier curves). Paths can be used to create complex selections around natural curves, paths can also be named, saved, and painted (or "stroked") with brushes, patterns, or various line styles.

• Image editing: there are many tools that can be used for editing images in GIMP. The more common tools include a paint brush, pencil, airbrush, eraser and ink tools used to create new or blended pixels. Tools such as the bucket fill and blend tools are used to change large regions of space in an image and can be used to help blend images. GIMP also has a selection of smart tools, which are tools that use more complex mathematics to enable a user to do things that otherwise would be time consuming or impossible; these smart tools include the clone tool that copies pixels using a brush, the healing brush which copies pixels from an area and corrects the tone and color where it is being used. The perspective clone tool works in a similar way to the clone tool previously mentioned but also allows a user to correct for distance changes. The blur and sharpen tool is a brush that blurs and sharpens. Finally the dodge and burn tool is a brush that makes target pixels lighter (dodges) or darker (burns).
  A list of GIMP transform tools include the align tool, move, crop, rotate, scale, shear, perspective and flit tools.

Animation showing three docked and tabbed dialogs: layers, channels, and paths.

• Layers, layer masks and channels: an image being edited in GIMP can consist of many layers sitting in a stack. The GIMP user manual suggests that "A good way to visualize a GIMP image is as a stack of transparencies" where in GIMP terminology each transparency is a layer.^[26] Each layer in an image is made up of several channels. In an RGB image there are normally 3 or 4 channels, each consisting of a red, green and blue channel. Color sublayers look like slightly different gray images, but when put together they make a complete image. The fourth channel that may be part of a layer is the alpha channel (or layer mask), this channel measures opacity where a whole or part of an image can be completely visible, partially visible or invisible.

Text layers can be created using the text tool, allowing a user to write on an image. Text layers can be transformed in several ways, such as converting it to a path or selection.^[27][28]

• Automation, scripts and plug-ins: GIMP has approximately 150 standard effects and filters, including Drop Shadow, Blur, Motion blur and Noise.
  GIMP operations can be automated with scripting languages. The Script-Fu is a Scheme based extension language implemented using TinyScheme, GIMP can also be scripted in Perl, Python (Python-fu), or Tcl.

GIMP has support for several methods of sharpening and blurring images including the blur and sharpen tool. The unsharp mask tool is used to sharpen an image selectively - it only sharpens areas of an image that are sufficiently detailed. The unsharp mask tool is considered to give more targeted results for photographs than a normal sharpening filter.^[29][30] The Selective Gaussian Blur tool works in a similar way, except it blurs areas of an image with little detail.

• GEGL: The Generic Graphics Library (GEGL) was first introduced as part of GIMP on the 2.6 release of GIMP. This initial introduction does not yet exploit all of the capabilities of GEGL; as of the 2.6 release GIMP can use GEGL to perform high bit depth color operations, because of this less information is lost when performing color operations.^[31] When fully integrated, GEGL will allow GIMP to have a higher color bit depth and also a better non-destructive work-flow.

• File formats: GIMP supports saving and loading a large number of different file formats,^[32] GIMP's native format XCF is designed to store an image including all features specific to GIMP such as layers, channels and vectors; XCF is named after the eXperimental Computing Facility where GIMP was authored.

Variants

GIMP 2.2.8 running under X11 on Mac OS X

Several variations and derived graphic applications exist today, these applications can exist because GIMP is released under the GNU General Public License; the GPL specifically allows anybody to take the source code and use it as they see fit, so long as they follow the rules laid out in the license. GIMP is available on many popular operating systems, even so, some variants of GIMP exist for OS-specific modifications.

The GIMP website only offers source code downloads; executable version of GIMP are made available by other sources.

• GIMP Online is the online web browser version for GIMP and GTK+, where GIMP is in a cloud computing environment. This allows non-technical users to launch GIMP on demand without downloading and installing to the hard drive.

• GIMP Visual Studio (GIMPVS) is a derivative of GIMP and GTK+ that is compiled using Microsoft compilers. GIMPVS aims to provide a stable GIMP for artists using Microsoft Windows and allowing developers to program with GTK+ and GIMP using Microsoft Visual Studio.^[33]

• Seashore is a program derived from GIMP running in native Mac OS X. The program is currently in beta and includes a subset of the tools and features in GIMP.

• GIMP.app is a distribution of GIMP built for Mac OS X. GIMP.app has all the features of the default GIMP distribution. GIMP.app has both a version using X11 and a version native to the Mac, but the latter is considered experimental.^[34]

• osx-gimp provides a native beta build of an old (2.2.14) version of GIMP on Mac OS X using GTK+ built for Quartz. It is mostly functional, but support is limited for the Quartz back-end of GTK+. It is only available for PPC Macs.^[35]

• CinePaint, formerly "Film Gimp", is a fork of GIMP version 1.0.4, used for frame-by-frame retouching of feature film. The present version supports up to 32-bit IEEE-floating point color depth per channel. CinePaint supports color management and HDR. CinePaint is used primarily within the film industry due mainly to its support of high-fidelity image formats.

• GIMP Portable is a portable version of GIMP that can be installed on a USB hard drive such that brushes and presets are the same from one computer to the next. GIMP Portable is only portable between different computers running Microsoft Windows (XP or later).^[36]

• GIMP Animation Package (GAP) is an advanced plug-in for GIMP for creating animations, it extends GIMP's normal capabilities. GAP is capable of saving animations in several formats including GIF and AVI.^[37] The animation function relies on the layering capability of GIMP. By creating separate layers and treating each one as an animation cell, then placing and rotating image layers within time constraints, the animation effect is produced. In this way, an animated GIF or encoded video file can be produced. GAP has further functionality in that different programmed layer transitions and timing as well as move paths are available this allows for the creation of sophisticated animations.

• GIMP Paint Studio (GPS) is a collection of brushes and accompanying tool presets for GIMP aimed at artists and graphic designers. It is intended to speed up repetitive tasks; a faster work-flow is achieved by saving tool presets between uses.^[38]

• GIMPshop is a derivative of GIMP that re-arranges the user interface to mimic Adobe Photoshop. This is achieved by modifying menus and user interface items. GIMPshop is released on Microsoft Windows.

• GimPhoto has a similar aim to GIMPshop, but has been made using a more recent version of GIMP.^[39] GimPhoto is targeted toward photographers who have previously used Adobe Photoshop. It is available for both Microsoft Windows and Linux.

• Instrumented GIMP was created at the University of Waterloo to track and report user interaction with the program, in so doing they are able to generate statistics about how GIMP is used.

• GIMP classic is a patch^[40] against the 2.6.8 GIMP source code that was created to undo the changes made to the GIMP user interface between the 2.4 and 2.6 versions. A build of GIMP classic for Ubuntu is available from launchpad.net.^[41]

Wilber

Wilber, the mascot of GIMP

The official mascot of GIMP, Wilber was created by Tuomas Kuosmanen (tigert) at some point before 25 September 1997; since then Wilber has received additional accessories from other GIMP developers.^[42] Accessories for Wilber can be found in the Wilber construction kit, included with the GIMP source code.^[42]

Wilber is also used as a free software cultural reference outside of GIMP, for example Wilber can be played as a racing car driver in SuperTuxKart along with other free software cultural icons.^[43] In addition to being referenced in other software projects, Wilber has been shown on the side of the Bibliothèque nationale de France as part of Project Blinkenlights.^[44]

Development

GIMP is primarily developed by volunteers, however, the GIMP project has a development branch, unstable branches and stable branches. New features are added to the development branch of GIMP, when the developers decide that there are enough new features they begin the process of creating a release. The process starts off by creating an unstable branch from the development branch; this unstable branch will be stabilized and will receive bug-fixes until it is ready to replace the existing stable branch. GIMP has adopted a scheme used by many other free and open source software projects, the second number in a version, for example 2.6.6, denotes whether a GIMP release is stable or unstable, an odd number means an unstable version and an even number means a stable version. The final number represents the number of bug-fix releases after a stable or unstable branch is released. As of July 2010^[update], the current stable version of GIMP is 2.6.10.

Each year GIMP applies for several positions in the Google Summer of Code (GSoC),^[45][46] to date GIMP has participated in all years except 2007.^[47] From 2006 to 2009 there have been 9 GSoC projects that have been listed as successful,^[45] although not all successful projects have been merged into GIMP yet. The healing brush and perspective clone tools and Ruby bindings were created as part of the 2006 GSoC and can be used in the current version of GIMP, although there were three other projects that were completed and are not yet available in a stable version of GIMP; those projects being Vector Layers, a JPEG 2000 plug-in. Several projects were completed in 2008, but none are yet a part of a stable release of GIMP.

Libre Graphics Meetings

The Libre Graphics Meeting (LGM) is a yearly event where developers of GIMP and other projects meet up to discuss issues related to free and open source graphics software. The GIMP developers take the opportunity to hold birds of a feather (BOF) sessions at this event.

Distribution

GIMP is released as source code under the GNU General Public License as free software.^[48] The current version of GIMP works with numerous operating systems, including Linux, Mac OS X and Microsoft Windows. Many Linux distributions include GIMP as a part of their desktop operating systems, including Debian and Fedora. Due to file size constraints, Ubuntu no longer includes GIMP as of Ubuntu 10.04, but it remains available for installation via the package manager.

A port of GIMP to Microsoft Windows was started by Tor Lillqvist in 1997. The GIMP website links to binary installers compiled by Jernej Simončič for the platform.^[49] MacPorts is listed as the recommended provider of recent Mac builds of GIMP,^[50] MacPorts also provides builds of other free and open source software applications and provides tools to make doing so simpler.^[51] Mac OS X can optionally use an X11 server; GTK+ was originally designed to run on an X11 server, as such porting GIMP to Mac OS X was much simpler than creating a Windows port.

There is no stable 64 bit Windows distribution version of GIMP available as of December 2009.

See also

• Image editing
• Comparison of raster graphics editors
• List of raster graphics editors
• Libre Graphics Meeting
• Linux color management

References

External links

• Official GIMP website
• Portable GIMP
• GIMP at the Open Directory Project
• Resources to learn GIMP
  • Official GIMP user manual (English) or (other languages)
  • (book) Montabone, Sebastian (2010). Beginning Digital Image Processing: Using Free Tools for Photographers. Apress. ISBN 9781430228417. 
  • (book) Grokking the GIMP
  • (book) Beginning GIMP: From Novice to Professional, Second Edition--a new book covering 2.4 and previewing 2.6

• GIMP news, and news aggregation
  • GIMP at Freshmeat

• Wilber (the GIMP mascot) links
  • Wilber images at the GIMP homepage (near bottom)
  • Wilber on the Bibliothèque nationale de France (photo taken at a Project Blinkenlights installation in Paris)

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