Lecture+4
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- Words: 704
- Pages: 6
Sections from Chapter2
Overview of Graphics Systems
Included: 2.1,
2.2, 2.3, 2.5, 2.6
Not included: 2.4,
2.7
13th April 2006
http://www.howstuffworks.com
Output devices Display devices (CRT/DVST/LCD). Printers.
Dot
Matrix.
Inkjet/Laser.
Plotters.
1
Direct-View storage tube
Primary Flood
gun stores the picture definition. gun maintains the picture display.
Advantages. No
refreshing needed, so complex pictures can be drawn without flicker.
Flat Panel displays
2 electron guns are used.
Disadvantages.
Class of video devices that have reduced volume, weight and power requirement as compared to CRT’s. Thinner than CRT’s so we can hang them on walls and wear on our wrists. Used in:
Selected
parts of a picture cannot be erased and redrawn.
Emissive displays. Convert
electrical energy into light.
Plasma panels. Thin-film electroluminescent displays. Light-emitting diodes.
monitors, laptop computers, calculators, pocket video games etc.
Used in: Analog Oscilloscopes.
Categories of Flat panel displays
TV
Non-Emissive displays. Use
optical effects to convert sunlight or light into graphics patterns.
Liquid Crystal Displays.
Plasma Panels
Consists of: Two
glass plates. Electrodes sandwiched between these plates. Noble gases e.g. neon or xenon is contained within these plates Area between the glass plates is divided into tiny cells, each of which can be considered as a pixel.
2
Pros & Cons of Plasma Panels
Pros a very wide screen using extremely thin materials. Image produced is very bright and looks good from almost every angle.
Light emitting diodes
Produce
Cons
Expensive.
they
form the numbers on digital clocks, information from remote controls light up watches. tell you when your appliances are turned on. Illuminate traffic lights. transmit
Thin-film electroluminescent displays are similar to plasma panels in construction except for the fact that the inner gas is replaced by phosphor. Requires more power to light up
Liquid crystal display Used in calculators, portable laptops etc. They produce a picture by passing polarized light from the surrounding or from an internal light source through a liquid-crystal material that can be aligned to either block of transmit the light.
Simply said, LED’s are just tiny light bulbs that fit easily into an electrical circuit. Unlike ordinary bulbs, they don’t have a filament that will burn out, and they don’t get very hot. Applications:
Dot-Matrix printer
A dot matrix printer refers to a type of computer printer with a print head that runs back and forth on the page and prints by impact, striking an ink-soaked cloth ribbon against the paper, much like a typewriter.
3
Inkjet printer
Laser printer A laser printer is a common type of computer printer that produces high quality printing, and is able to produce both text and graphics. Principle is based on that of a photocopy machine.
Produces output by squirting ink in horizontal rows across a roll of paper wrapped on a drum.
Plotter A plotter is a vector graphics printing device that connects to a computer. Plotters print their output by moving a pen across the surface of a piece of paper.
Restricted
to line art, rather than raster graphics as with other printers. They can draw complex line art, including text, but do so very slowly because of the mechanical movement of the pens. Plotters are incapable of creating a solid region of colour.
RASTER-SCAN SYETEM
Interactive raster graphics systems typically employ several processing units apart from the CPU, which are: Video
Controller processor
Display
4
Video Controller
video controller controls: Display
Refresh
device.
How pixels coordinates are determined?
operations.
Double buffering.
Areas of screen enlarged, reduced and moved to different locations. Look-up table. Mix of frame-buffer image and another image
Back
Display processor
display processor performs: raster
graphics operations (instead of CPU).
Scan conversion. Character Definition. Line styles.
Dashed,
dotted, solid.
Interface with input device (e.g.mouse). Memory requirements for the frame buffer?
5
Raster-Scan Characters
Back
6
Overview of Graphics Systems
Included: 2.1,
2.2, 2.3, 2.5, 2.6
Not included: 2.4,
2.7
13th April 2006
http://www.howstuffworks.com
Output devices Display devices (CRT/DVST/LCD). Printers.
Dot
Matrix.
Inkjet/Laser.
Plotters.
1
Direct-View storage tube
Primary Flood
gun stores the picture definition. gun maintains the picture display.
Advantages. No
refreshing needed, so complex pictures can be drawn without flicker.
Flat Panel displays
2 electron guns are used.
Disadvantages.
Class of video devices that have reduced volume, weight and power requirement as compared to CRT’s. Thinner than CRT’s so we can hang them on walls and wear on our wrists. Used in:
Selected
parts of a picture cannot be erased and redrawn.
Emissive displays. Convert
electrical energy into light.
Plasma panels. Thin-film electroluminescent displays. Light-emitting diodes.
monitors, laptop computers, calculators, pocket video games etc.
Used in: Analog Oscilloscopes.
Categories of Flat panel displays
TV
Non-Emissive displays. Use
optical effects to convert sunlight or light into graphics patterns.
Liquid Crystal Displays.
Plasma Panels
Consists of: Two
glass plates. Electrodes sandwiched between these plates. Noble gases e.g. neon or xenon is contained within these plates Area between the glass plates is divided into tiny cells, each of which can be considered as a pixel.
2
Pros & Cons of Plasma Panels
Pros a very wide screen using extremely thin materials. Image produced is very bright and looks good from almost every angle.
Light emitting diodes
Produce
Cons
Expensive.
they
form the numbers on digital clocks, information from remote controls light up watches. tell you when your appliances are turned on. Illuminate traffic lights. transmit
Thin-film electroluminescent displays are similar to plasma panels in construction except for the fact that the inner gas is replaced by phosphor. Requires more power to light up
Liquid crystal display Used in calculators, portable laptops etc. They produce a picture by passing polarized light from the surrounding or from an internal light source through a liquid-crystal material that can be aligned to either block of transmit the light.
Simply said, LED’s are just tiny light bulbs that fit easily into an electrical circuit. Unlike ordinary bulbs, they don’t have a filament that will burn out, and they don’t get very hot. Applications:
Dot-Matrix printer
A dot matrix printer refers to a type of computer printer with a print head that runs back and forth on the page and prints by impact, striking an ink-soaked cloth ribbon against the paper, much like a typewriter.
3
Inkjet printer
Laser printer A laser printer is a common type of computer printer that produces high quality printing, and is able to produce both text and graphics. Principle is based on that of a photocopy machine.
Produces output by squirting ink in horizontal rows across a roll of paper wrapped on a drum.
Plotter A plotter is a vector graphics printing device that connects to a computer. Plotters print their output by moving a pen across the surface of a piece of paper.
Restricted
to line art, rather than raster graphics as with other printers. They can draw complex line art, including text, but do so very slowly because of the mechanical movement of the pens. Plotters are incapable of creating a solid region of colour.
RASTER-SCAN SYETEM
Interactive raster graphics systems typically employ several processing units apart from the CPU, which are: Video
Controller processor
Display
4
Video Controller
video controller controls: Display
Refresh
device.
How pixels coordinates are determined?
operations.
Double buffering.
Areas of screen enlarged, reduced and moved to different locations. Look-up table. Mix of frame-buffer image and another image
Back
Display processor
display processor performs: raster
graphics operations (instead of CPU).
Scan conversion. Character Definition. Line styles.
Dashed,
dotted, solid.
Interface with input device (e.g.mouse). Memory requirements for the frame buffer?
5
Raster-Scan Characters
Back
6
