GTK+ was originally developed for GIMP, the GNU Image Manipulation Program. GTK+ stands for the GIMP Tool Kit. GTK+ has grown from these beginnings and is now used as a central part of Gnome, the GNU Projects desktop environment. GTK+ has also been ported to BeOS and Win32, making it the perfect choice to use as the basis for a PHP extension, keeping PHP as cross-platform as possible and allowing the creation of windowed applications in PHP for Linux, BeOS and Windows.