Computer graphics, production of images on computers for use in any medium. Images use in printed graphic design are produce on computers, as are still and moving images seen in comic strips and animations. Without modern computer graphics, electronic games and computer simulations would not be possible.

In scientific visualization, images and colors are use to model complex phenomena such as air currents and electric fields. They are also essential to computer-aided engineering and design, in which objects are drawn and analyzed in computer programs. Even the Windows-based graphical user interface, now a common means of interacting with innumerable computer programs, is a product of computer graphics.

Image Display Graphics

Images have high information content, both in terms of information theory, the number of bits required to represent images and in terms of semantics, the meaning images can convey to the viewer. Because of the importance of images in any domain where complex information is display or manipulate. In addition, because of the high expectations consumers have of image quality, computer graphics have always placed heavy demands on computer hardware and software.

In the 1960s early computer graphics systems used vector graphics to construct images out of straight line segments. These images combine for display on specialized computer video monitors. Vector graphics is economical in memory use, as an entire line segment is specified simply by the coordinates of its endpoints. However, it is inappropriate for highly realistic images, since most images have curved edges. Using all straight lines to draw curved objects results in a noticeable stair-step effect.

3-D Rendering Graphics

Although used for display, bitmaps are not appropriate for most computational tasks, which need a three-dimensional representation of the objects composing the image. One standard benchmark for computer model rendering into graphical images is the Utah Teapot, created at the University of Utah in 1975. Represented skeletally as a wire-frame image, the Utah Teapot is compose of many small polygons. However, even with hundreds of polygons, the image is not smooth

Smoother representations can be provided by Bezier curves, which have the further advantage of requiring less computer memory. Bezier curves are describe by cubic equations. A cubic curve is determine by four points or, equivalently, by two points and the curve’s slope at those points. Two cubic curves can be smoothly join by giving them the same slope at the junction. Bezier curves, and related curves known as B-splines, introduce in computer-aided design programs for the modeling of automobile bodies.

Shading And Texturing Graphics

Visual appearance includes more than just shape and colour texture and surface finish, matte, satin, glossy also must be accurately model. The effects these attributes have on an object’s appearance depend on its illumination. This may be diffuse, from a single source, or both. There are several approaches to rendering the interaction of light with surfaces.

The simplest shading techniques are flat, Gouraud, and Phong. Flat shading uses no textures and only one color tone is use for the entire object. Different amounts of white or black are add to each object face to simulate shading. The shading techniques described thus far do not model specular reflection from glossy surfaces or model transparent and translucent objects. This can be done by ray tracing, a rendering technique that uses basic optical laws of reflection and refraction.

Processors And Programs

One way to reduce rendering time is to use parallel processing. This is so that in ray shading, for example, multiple rays can be trace at once. Another technique, pipelined parallelism, takes advantage of the fact that graphics processing can be broken into stages constructing polygons or Bezier surfaces, eliminating hidden surfaces, shading, rasterization, etc.

Using pipeline parallelism, as one image is being rasterize, another can be shade, and a third can be construct. Both kinds of parallelism are employ in high-performance graphics processors. Demanding applications with many images may also use farms of computers. Even with all of this power, it may take days to render the many images required for a computer-animated motion picture.