Frequently asked questions with answers...4

13. What is meant by computer graphics?
Ans. Like in television, the screen of computer monitor can be devided into a large no. of small square areas called pixels. Each pixel occupies
a fixed position on the screen, thus can be mapped. The color of a pixel and its position is decided by computer graphics system.A RAM
memory module holds the color information of each pixel. A hardware card known as graphics adapter interacts between the RAM memory holding the pixel details and the monitor electronics. The picture on the screen is refreshed 25 to 30 times a second to generate a static picture for human perception.The RAM memory area can hold 800 X 600 or 640 X 480 or 1024 X 768 pixel details. One pixel may occupy 1 bit to 3 bytes(24 bits). This system forms the basic bitmap image for a computer screen. Thus a blank screen, a text page, colored images or animation have to be handled by the bit mapped graphic system. Depending on the software being used CPU generates the color content bytes for the RAM memory to be displayed by the monitor.

14. How many colors are possible and how to control colors?
Ans. The idea of generation of color is taken from television technology. Three color guns Red, Blue and green produce the vast range of colors that we see. Imagine a control system for any of the guns where the strength of the gun can be uniformly changed in minutely small steps. Let us devide the total range of each gun into 256 steps. So 256 X 256 X 256 no. of colors are generated by varying the strengths of all the three guns. Any pixel can have one out of this number(65,536) of colors. The imaging softwares and drawing application programs like paintbrush, paintshop, adobe etc give us choice of varying this number in steps of 1 for each of color red, blue or green.

15. What is ASCII character?
Ans. ASCII stands for American Standard Code for Information Interchange.Each alphabet, uppercase or lower case, each digit, comma, full stop etc are given a seperate unique code for transmission and reception. A uniform length of 8 bits or a byte is assigned to each of these characters as an ascii code. thus there are total 256 such codes found universally in all computers. Fontface and non-english characters are designed on the basis of ascii codes. Printers and monitors are driven by driver softwares which decode these codes to generate the regional characres on the screen or paper.

16. What is the difference between analog and digital?
Ans. A digital system quantifies an analog quantity in a number system based on 2. In analog system number basis is 10 with no mention of how many digits after decimal point. In digital system, digits are 1 and 0 with decided length of no. of places. It is somewhat difficult for humans to read or assess a digital number, but machines find it easier to to handle 1s and 0s compared to 10 different digits of an analog system.The treatment of analog and digital quantities in electronic systems call for entirely different circuits. Computers can not treat analog quantities easily, so analog is converted to digital for any processing or manipulations, the results are reconverted to analog form for display or printing.

Frequently asked questions with answers

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