Model of a computer graphics system:
A computer graphics system must have all the components of a general purpose computer system. Typically those components are following:
1. Input devices ( Mouse, keyboard, Joystick, Digital pen)
2. Output devices ( Digital display, extended digital display)
3. Processor
4. Memory
5. Frame Buffer
Most of the computation in computer graphics is targeted to frame buffer so it should be given a due attention.
Frame Buffer:
Almost all graphics system are Raster based systems. In Raster based system, entire screen is divided into picture elements which is called pixels. Information is displayed on screen by assigning a color to each pixel.
A picture is also called a raster- an array of pixels.
All pixels are stored in a buffer (placed in RAM) and its is called Frame buffer.
Resolution of Frame buffer: determined by number of pixels.
Depth of frame buffer: determined by number of bits assigned to each pixel for storing color information.
Example:
- 1- bit deep frame buffer can have only 2 colors (Black, white).
- 8-bit deep frame buffer can have only 256 colors.
- 24-bit deep frame buffer is said a true color system or full-color system.
True color system is also called RGB color system because every color is made up of 3 primary colors (Red, green, Blue) and for each pixel distribution of 24 bits is as follows:
[8 bits (Red)] [8 bits (Green)] [8 bits (Blue)]
