GDK
Encyclopedia
GDK is a computer graphics
library
that acts as a wrapper around the low-level drawing and windowing functions provided by the underlying graphics system. Originally developed on the X Window System
for the GIMP
image manipulation program, GDK lies between the X server and the GTK+
library, handling basic rendering such as drawing primitives, raster graphics
(bitmaps), cursor
s, font
s, as well as window events and drag-and-drop
functionality.
Like GTK, GDK is licensed under the GNU Lesser General Public License
.
GDK is an important part of GTK+'s portability. Since low-level cross-platform functionality is already provided by GLib
, all that is needed to make GTK+ run on other platforms is to port GDK to the underlying operating system
's graphics layer. Hence, the GDK ports to Win32 and Quartz
are what makes GTK+ applications run on Windows
and Mac OS X
, respectively.
Starting with GTK+ 2.8, GDK supports Cairo
.
Computer graphics
Computer graphics are graphics created using computers and, more generally, the representation and manipulation of image data by a computer with help from specialized software and hardware....
library
Library (computer science)
In computer science, a library is a collection of resources used to develop software. These may include pre-written code and subroutines, classes, values or type specifications....
that acts as a wrapper around the low-level drawing and windowing functions provided by the underlying graphics system. Originally developed on the X Window System
X Window System
The X window system is a computer software system and network protocol that provides a basis for graphical user interfaces and rich input device capability for networked computers...
for the GIMP
GIMP
GIMP is a free software raster graphics editor. It is primarily employed as an image retouching and editing tool and is freely available in versions tailored for most popular operating systems including Microsoft Windows, Apple Mac OS X, and Linux.In addition to detailed image retouching and...
image manipulation program, GDK lies between the X server and the GTK+
GTK+
GTK+ is a cross-platform widget toolkit for creating graphical user interfaces. It is licensed under the terms of the GNU LGPL, allowing both free and proprietary software to use it. It is one of the most popular toolkits for the X Window System, along with Qt.The name GTK+ originates from GTK;...
library, handling basic rendering such as drawing primitives, raster graphics
Raster graphics
In computer graphics, a raster graphics image, or bitmap, is a data structure representing a generally rectangular grid of pixels, or points of color, viewable via a monitor, paper, or other display medium...
(bitmaps), cursor
Cursor (computers)
In computing, a cursor is an indicator used to show the position on a computer monitor or other display device that will respond to input from a text input or pointing device. The flashing text cursor may be referred to as a caret in some cases...
s, font
Font
In typography, a font is traditionally defined as a quantity of sorts composing a complete character set of a single size and style of a particular typeface...
s, as well as window events and drag-and-drop
Drag-and-drop
In computer graphical user interfaces, drag-and-drop is the action of selecting a virtual object by "grabbing" it and dragging it to a different location or onto another virtual object...
functionality.
Like GTK, GDK is licensed under the GNU Lesser General Public License
GNU Lesser General Public License
The GNU Lesser General Public License or LGPL is a free software license published by the Free Software Foundation . It was designed as a compromise between the strong-copyleft GNU General Public License or GPL and permissive licenses such as the BSD licenses and the MIT License...
.
GDK is an important part of GTK+'s portability. Since low-level cross-platform functionality is already provided by GLib
GLib
GLib is a cross-platform software utility library that began as part of the GTK+ project. However, before releasing version 2 of GTK+, the project's developers decided to separate non-GUI-specific code from the GTK+ platform, thus creating GLib as a separate product...
, all that is needed to make GTK+ run on other platforms is to port GDK to the underlying operating system
Operating system
An operating system is a set of programs that manage computer hardware resources and provide common services for application software. The operating system is the most important type of system software in a computer system...
's graphics layer. Hence, the GDK ports to Win32 and Quartz
Quartz (graphics layer)
Quartz specifically refers to a pair of Mac OS X technologies, each part of the Core Graphics framework: Quartz 2D and Quartz Compositor. It includes both a 2D renderer in Core Graphics and the composition engine that sends instructions to the graphics card...
are what makes GTK+ applications run on Windows
Microsoft Windows
Microsoft Windows is a series of operating systems produced by Microsoft.Microsoft introduced an operating environment named Windows on November 20, 1985 as an add-on to MS-DOS in response to the growing interest in graphical user interfaces . Microsoft Windows came to dominate the world's personal...
and Mac OS X
Mac OS X
Mac OS X is a series of Unix-based operating systems and graphical user interfaces developed, marketed, and sold by Apple Inc. Since 2002, has been included with all new Macintosh computer systems...
, respectively.
Starting with GTK+ 2.8, GDK supports Cairo
Cairo (graphics)
cairo is a software library used to provide a vector graphics-based, device-independent API for software developers. It is designed to provide primitives for 2-dimensional drawing across a number of different backends...
.