COMPUTER GRAPHICS (XCS 354) UNIT – I

16. What are the features of Inkjet printers? 

•  They can print 2 to 4 pages/minutes. 
• Resolution is about 360d.p.i. Therefore better print quality is achieved. 
• The operating cost is very low. 
• The only part that requires replacement is ink cartridge. 
• 4 colors cyane, yellow, majenta, black are available. 

17. What are the advantages of laser printer 

• High speed, precision and economy.
• Cheap to maintain.
• Quality printers.
• Lasts for longer time.
• Toner power is very cheap.

18. What are the advantages of electrostatic plotters? 
• They are faster than pen plotters and very high quality printers.
• Recent electrostatic plotters include a scan-conversion capability.
• Color electrostatic plotters are available. They make multiple passes over the paper to plot color pictures.

19. Define pixel? 
Pixel is shortened forms of picture element. Each screen point is referred to as pixel or pel.

20. What is frame buffer? 
Picture definition is stored in a memory area called frame buffer or refresh buffer.

COMPUTER GRAPHICS (XCS 354) UNIT – I

1. Define Computer graphics. 
Computer graphics remains one of the most existing and rapidly growing  computer fields. Computer graphics may be defined as a pictorial representation or graphical representation of objects in a computer.

2. What is meant by scan code? 
When a key is pressed on the keyboard, the keyboard controller places a code carry to the key pressed into a part of the memory called as the keyboard buffer. This code is called as the scan code.

3. What is meant by refreshing of the screen? 
Some method is needed for maintaining the picture on the screen. Refreshing of screen is done by keeping the phosphorus glowing to redraw the picture repeatedly. (i.e.)By quickly directing the electronic beam back to the same points.

4. Define Random scan/Raster scan displays? 
Random scan is a method in which the display is made by the electronic beam which is directed only to the points or part of the screen where the picture is to be drawn.
The Raster scan system is a scanning technique in which the electrons sweep from top to bottom and from left to right. The intensity is turned on or off to light and unlight the pixel.

5. List out the merits and demerits of Penetration techniques? 
The merits and demerits of the Penetration techniques are as follows

• It is an inexpensive technique
• It has only four colors
• The quality of the picture is not good when it is compared to other techniques
• It can display color scans in monitors
• Poor limitation etc.

6. List out the merits and demerits of DVST? 
The merits and demerits of direct view storage tubes [DVST] are as follows
•It has a flat screen
•Refreshing of screen is not required
•Selective or part erasing of screen is not possible
•It has poor contrast
•Performance is inferior to the refresh CRT.


7. What do you mean by emissive and non-emissive displays?
The emissive display converts electrical energy into light energy. The plasma panels, thin film electro-luminescent displays are the examples. The Non emissive are optical effects to convert the sunlight or light from any other source to graphic form. Liquid crystal display is an example.