GNUstep

GNUstep
Company type	Free software project
Industry	Software development, widget toolkit
Founded	1994
Founder	Paul Kunz and associates at the Stanford Linear Accelerator Center
Area served	Cross-platform (Unix-like systems, Microsoft Windows)
Products	Objective-C libraries, widget toolkit, development tools
Owner	GNU Project
Parent	GNU Project
Website	www.gnustep.org

GNUstep represents a free software realization of the Cocoa frameworks—previously known as OpenStep—including the Objective-C libraries, widget toolkit, and development tools designed for Unix-like platforms as well as Microsoft Windows. It forms an integral component of the GNU Project.

Providing a platform-independent, object-oriented IDE, GNUstep extends support beyond its native Objective-C interface by offering bindings for languages such as Java, Ruby, GNU Guile, and Scheme. The project maintains alignment with Apple's Cocoa by closely monitoring its updates. Both GNUstep and Cocoa share a common heritage rooted in NeXTSTEP and OpenStep. Notably, GNUstep predates Cocoa, having been originally developed by GNU contributors to emulate NeXTSTEP’s programmer-centric environment.

History

The inception of GNUstep traces back to efforts by Paul Kunz and associates at the Stanford Linear Accelerator Center, who aimed to adapt HippoDraw from its original NeXTSTEP platform to other operating systems. Rather than rewriting HippoDraw from scratch, they reconstructed the NeXTSTEP object layer it depended upon, resulting in the creation of libobjcX. This approach enabled HippoDraw to operate on Unix systems running the X Window System without altering its source code. Following the 1994 release of the OpenStep specification, they developed a revised objcX implementation compliant with these APIs, which subsequently evolved into what is now known as GNUstep.

Software architecture

The Foundation Kit supplies fundamental classes including wrappers and data structures, while the Application Kit concentrates on delivering graphical user interface functionalities. GNUstep encompasses a collection of Objective-C-based graphical control elements.

GNUstep’s graphical interface, demonstrated by applications like GNUMail, interfaces with windowing systems such as the X11 or Wayland. Its backend components provide mechanisms for communication with these systems and incorporate a rendering engine that simulates typical Postscript operations. The gnustep-back package comprises:

cairo – the standard backend utilizing the 2D graphics library Cairo.
winlib – the default backend for Microsoft Windows platforms, supporting both Cairo and variants of the Windows API.
art – an obsolete backend for Unix-like environments employing the vector-based PostScript-like 2D library Libart.
xlib – a deprecated backend for X11 systems.

GNUstep’s design philosophy draws heavily from OPENSTEP—which predates Cocoa and forms its foundation—and Objective-C, incorporating features such as:

The Model–view–controller architecture
The Target–action mechanism
Support for Drag-and-drop
Use of Delegation
Message forwarding through NSInvocation

Further GNUstep initiatives seek to replicate Apple’s APIs:

The Boron library addresses the partially implemented Carbon API.
CoreBase is intended to provide compatibility with Core Foundation, though it does not fully substitute the Base (Foundation Kit).
QuartzCore delivers functionality for Core Animation, while Opal implements features of Quartz 2D.

As of early 2020, there are no projects available that compile the Swift programming language within GNUstep’s Objective-C runtime environment.

Applications

Several prominent applications have been either created specifically for GNUstep or adapted to run on it:

Native Applications

Addresses – a contact management tool
Étoilé – a complete desktop environment
GNUMail – an email client
GNUstep Database Library 2 – a clone of the Enterprise Objects Framework
GNUstepWeb – an application server compatible with WebObjects version 4.x
Gorm – a user interface designer included in GNUstep’s developer tools, supporting '.nib' and '.gorm' formats; serves as the counterpart to Apple's Interface Builder
GWorkspace – a file manager and workspace environment
Grr – an RSS feed aggregator
Oolite – a space simulation game inspired by Elite, incorporating trading mechanics
PRICE – an image processing application
ProjectCenter – analogous to Project Builder or Xcode
TalkSoup – an IRC client
Terminal – terminal emulator
Zipper – utility for archiving files
Window Maker – a window manager that replicates NeXTSTEP’s graphical interface in an OpenStep-compatible setting; introduced in 1997 as an improved version of AfterStep

Ports from NeXTSTEP, OPENSTEP, or macOS

Adun
BioCocoa
Chess
Cenon
DoomEd
EdenMath
Eggplant
Emacs
Fortunate
Gomoku
NeXTGO
PikoPixel
TextEdit
TimeMon

GNUstep Derivatives

Universal Windows Platform (UWP), which includes the WinObjC suite blending GNUstep elements with Microsoft's implementations of APIs such as Cocoa Touch

External links