Computer graphics, a subfield of computer science, is concerned with digitally
synthesizing and manipulating visual content. Although the term often refers to
three-dimensional (3D) computer graphics, it also encompasses two-dimensional
(2D) graphics and image processing. Graphics is often differentiated from the field
of visualization, although the two have many similarities. Entertainment (in the
form of animated movies and video games) is perhaps the most well-known
application of computer graphics.Today, computer graphics can be seen in almost
every illustration made. Computer graphics are often used by photographers to
improve photos. It also has many other applications, ranging from the motion
picture industry to architectural rendering. As a tool, computer graphics, which
were once
very expensive and complicated, can now be used by anyone in the
form of freeware. In the future, computer graphics could possibly replace
traditional drawing or painting for illustrations. Already, it is being used as a form
of enhancement for different illustrations.Modeling describes the shape of an
object. The two most common sources of 3D models are those
created by an
artist using some kind of 3D modeling tool, and those scanned into a computer
from real-world objects. Models can also be produced procedurally or via physical
simulation.
Because the appearance of an object depends largely on the
exterior of the
object, boundary representations are most common in computer graphics. Two
dimensional surfaces are a good analogy for the objects used in graphics, though
quite often these objects are non-manifold. Since
surfaces are not finite, a
discrete digital approximation is required: Polygonal meshes (and to a lesser
extent subdivision surfaces) are by far the most common representation,
although point-based representations have been gaining some popularity in
recent years. Level sets are a useful representation for deforming surfaces which
undergo many topological changes such as fluids.2D computer graphics is the
computer-based generation of digital images—mostly from two-dimensional
models (such as 2D geometric models, text, and digital images) and by techniques
specific to them. The term may stand for the branch of computer science that
comprises such techniques, or for the models themselves.
2D computer graphics are mainly used in applications that were
originally
developed upon traditional printing and drawing technologies, such as
typography, cartography, technical drawing, advertising, and so on. In those
applications, the two-dimensional image is not just a representation of a real-
world object, but an independent artifact with added semantic value; two-
dimensional models are therefore preferred, because they give more direct
control of the image than 3D computer graphics (whose approach is more akin to
photography than to typography).
In many domains, such as desktop publishing, engineering, and business, a
description of a document based on 2D computer graphics techniques can be
much smaller than the corresponding digital image—often by a factor of 1/1000
or more. This representation is also more
flexible, since it can be rendered at
different resolutions to suit different output devices. For these reasons,
documents and illustrations are often stored or transmitted as 2D graphic files.
2D computer graphics started in the 1950s, based on vector graphics devices.
These were largely supplanted by raster-based devices in the following decades.
The PostScript language and the X Window System protocol were landmark
developments in the field.