A College Project to Avoid a Compiler Class
The story begins in 1995 at the University of California, Berkeley. Two undergraduate students, Spencer Kimball and Peter Mattis, were faced with a computer science project they weren't excited about. Instead of building a compiler, they decided to try
something more interesting: creating a pixel-based image editor from scratch. Neither had a background in graphic arts, but after about nine months of work, they released version 0.54 of the 'General Image Manipulation Program', or GIMP, to the public in early 1996. It was an impressive student project, complete with a plug-in system and basic editing tools. The nascent open-source community took notice, but one major hurdle stood in the way of its widespread adoption.
The Problem with Proprietary Tools
The first version of GIMP was built using a graphical user interface (GUI) toolkit called Motif. A toolkit is essentially a box of pre-made software components—like buttons, menus, and sliders—that developers use to build an application's interface. The problem was that Motif was proprietary and commercial software. This meant that distributing GIMP freely and encouraging a community of developers to contribute was legally and practically impossible. Anyone who wanted to build upon GIMP would need a Motif license. This friction went against the entire ethos of the free software movement that was gaining momentum at the time. Frustrated by these limitations, Peter Mattis decided he wouldn't just work around the problem; he would replace the entire toolkit himself.
The Accidental Revolution: GTK Is Born
Mattis began writing a new, open-source toolkit from the ground up, specifically for GIMP. He called it the GIMP ToolKit, or GTK for short. Initially, there was no grand plan for GTK to be anything more than an internal component of their image editor. It was a classic case of 'scratching your own itch'. But the developers soon realized they had built something far more significant than just a part of GIMP. They had created a flexible, free, and powerful set of tools that any developer could use to build their own applications without the licensing headaches of toolkits like Motif. They separated GTK from GIMP, releasing it as a standalone library under the GNU Lesser General Public License (LGPL), which allowed it to be used by both free and proprietary software. This was the turning point.
From an Image Editor to a Desktop Empire
At the same time, in 1997, another major development was brewing in the Linux world. The popular KDE desktop environment was built on a toolkit called Qt, whose licensing terms were also controversial within the free software community. In response, developers Miguel de Icaza and Federico Mena launched a new project to create a completely free desktop environment: GNOME (GNU Network Object Model Environment). And what toolkit did they choose as its foundation? The newly independent and freely licensed GTK. Suddenly, the little toolkit born from an image editor became the bedrock of one of the most ambitious open-source projects in history. This decision transformed GTK from a niche library into a massive software infrastructure. An entire ecosystem of applications, from web browsers to office suites, was built using the very code that was first written to create the buttons and menus in GIMP.
