2D computer graphics are graphical images created with the aid of digital computers, in which two-dimensional visual techniques are employed. The term may also refer to the field of study or practice of two-dimensional computer graphics methods as a whole. 2D computer graphics typically do not involve the need for any kind of three-dimensional internal representation of objects or lighting characteristics in the computer; that field is customarily reserved for 3D computer graphics. Some primarily 2D software employs 3D techniques and concepts.
In 2D computer graphics, the computer screen may be considered as a canvas on which an image is drawn or composed. Several techniques exist for rendering 2D graphics on a computer screen; these may be broadly categorized into raster graphics, in which a rectangular array of pixels is drawn to the screen, and vector graphics, in which images are composed of mathematical representations of lines, curves, and other geometric shapes.
Modern computer graphics card displays almost overwhelmingly use raster techniques, dividing the screen into a rectangular grid of pixels, due to the relatively low cost of raster-based video hardware as compared with vector graphic hardware. Most graphic hardware has internal support for blitting operations and sprite drawing.
Many graphical user interfaces (GUIs), including Mac OS, Microsoft Windows, or the X Window System, are primarily based on 2D graphical concepts. Such software provides a visual environment for interacting with the computer, and commonly includes some form of window manager to aid the user in conceptually distinguishing between different applications.
The user interface within individual software applications is typically 2D in nature as well, due in part to the fact that most common input devices, such as the mouse, are constrained to two dimensions of movement.
Another common software implementation of 2D graphics takes the form of paint and drawing programs. These may also be conceptually divided into the Raster and Vector models. Raster graphics software, such as The GIMP, Photoshop, and Paint Shop Pro, customarily provides a two-dimensional drawing surface, analogous to a sheet of paper or canvas, which can be colored with lines, shapes, pasted graphics, and a wide array of other 2D visual objects. Images are manipulated and stored as a rectangular array of colored pixels.
Vector drawing programs include Adobe Illustrator and CorelDraw.
Such software utilizes concepts similar to the canvas and paint, but lines, shapes, and text are manipulated and stored as mathematical objects, rather than an array of pixels.
Graphics applications may often make use of both techniques in a complementary fashion; Photoshop and The GIMP, for example, include capabilities for drawing vector-based shapes, while Illustrator and CorelDRAW permit the inclusion of raster-based graphical elements.
Most early video games used only 2D graphics.
See also:
2D Graphics Hardware
2D Graphics Software