A computer is a device that processes data. It is a data storage, manipulation, and correlation tool. There are numerous methods for communicating processed data to the user. Computer graphics is one of the most effective and widely used methods of communicating processed data to users.
Instead of basic text, it presents information in the form of graphical objects such as photos, charts, graphs, and diagrams. As a result, we may claim that computer graphics allows us to express data visually. An engineering design, business graphs, architectural constructions, a single frame from an animated movie, or machine parts described for a service manual are all examples of pictures or graphics objects. In computer graphics, it is the most fundamental concept of coherence.
Computer Graphics helps us to find answers of following questions:
- How pictures or graphics objects are presented in computer graphics? How pictures or graphics objects are prepared for presentation?
- How previously prepared pictures or graphics objects are presented?
- How interaction with the picture or graphics object is accomplished?
Pictures or graphical objects are shown in computer graphics as a collection of discrete picture parts known as pixels.
The pixel is the smallest screen element that may be addressed. It is the tiniest portion of the display screen that we can manipulate. Control is performed by adjusting the brightness and colour of the pixels that make up the screen.
On a graphical display, each pixel does not represent a mathematical point. Instead, it denotes a zone that can possibly hold an endless number of points. For example, if we want to show point P with coordinates of (4.2, 3.8) and point P2 with coordinates of (4.8, 3.1), we can do so by using only one pixel (4, 3), as shown in following figure. A point is generally represented by the integer parts of x and y, i.e., pixel (int (x), int (y)).
The specific procedures identify which pixel will best approximate the desired image or graphics item.
Rasterization is the process of determining the proper pixels for a picture or graphics object, and scan conversion is the process of portraying a continuous picture or graphics object as a collection of discrete pixels.
Before presenting a picture, computer graphics allows for rotation, translation, scaling, and various projections. It also allows you to apply effects to the image before final representation, such as hidden surface removal, shading, or transparency.
It gives the user the ability to change the contents, structure, and look of photos or graphics objects using input devices such a keyboard, mouse, or a touch-sensitive panel on the screen.
The input devices and the display devices have a close interaction. As a result, graphics devices encompass both input and display devices.