Page 43 - DCAP504_Computer Graphics

Computer Graphics

The pick functions are performed by devices such as a light pen.

3.8 Summary

• Input devices are used to interact with the computer.
• Interactive devices can be either a pointing device or a positioning device.
• Graphics tablet, joystick, trackball, mouse and light pen are some of the pointing and positioning
devices.
• Output devices are used to display the processed information by the computer.
• The display devices provide graphical outputs in the form of hard copy or soft copy.
• The random scan displays are direct view storage tube display and calligraphic display.

• The raster scan display system refers to the rectangular pattern of image capture and
reconstruction in televisions.
• Printers are used in printing the information and images displayed on the monitor.
• The various modern printers include toner-based printer, liquid ink-jet printer, solid ink printer,
dye-sub limitation printer, inkless printers and UV printers.
• Projectors produce soft copy output. They are of two types: LCD projectors and DLP projectors.
• Image persistence refers to the ghost image that is formed when LCD monitors are run for a long
time with a fixed image.

• Resolution is the sharpness and clarity of an image.
• Frame buffer is that part of the memory which is reserved to hold the entire bit-mapped image
that is sent to the monitor.

• The I/O devices functioning capabilities are divided into four types, which include, locator
function, valuator function, choice or button function and pick function.
3.9 Keywords

Graininess: A photo which has poor definition because of large grain size
KB: Kilo Bytes
MB: Mega Bytes
MFPs: Multifunction Printers
Mpx: Megapixel
One Byte: 8 bits

Overscan: The Field Monitor zooms into the area that will be visible on most televisions
Persistence: Image persistence method used to protect display from the burn-in problem
Resolution: The level of information on a display device, such as a monitor
Underscan: Displays the full video frame, which is visible only on a production monitor
3.10 Self Assessment

1. State whether the following statements are true or false:
(a) Picture definition is stored in a memory area called the refresh buffer or frame buffer.
(b) Each screen point is referred to as a pixel or pel.

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