graphics display hardware
DESCRIPTION
Graphics Display Hardware. Display technologies CRT LCD Storage tube Drawing methods Vector Raster Architecture. Sketchpad. 1962 @ MIT Light pen Powered by “Whirlwind”, MIT’s prototype of the 1 st interactive computer Req’d high bandwidth Vector display Monochromatic. - PowerPoint PPT PresentationTRANSCRIPT
CS-321Dr. Mark L. Hornick
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Graphics Display Hardware
Display technologies CRT LCD Storage tube
Drawing methods Vector Raster
Architecture
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Sketchpad 1962 @ MIT Light pen Powered by “Whirlwind”,
MIT’s prototype of the 1st interactive computer
Req’d high bandwidth Vector display Monochromatic
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“Modern” Cathode Ray Tube (CRT)
Quasi-spherical screen
Phosphorescence period = 1/30 s to 1/60 s
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CRT – Sony Trinitron Slotted shadow mask Curvilinear screen Larger holes -- brighter image
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Vector Scanning• Electron beam can be arbitrarily directed• Number of displayable vectors is finite• Non-standard drive electronics
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1200-9600 baud serial
Begin
COLOR(a)MOVE(ix,iy)DRAW(ix,iy)
COLOR(b)DRAW(…)
End
Early hi-performance displays
MinicomputerDisplay Processor
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TektronixVector Display
T4010 512 x 512 ~$8,000
T4014 4096 x 3172 ~$18,000
PersistentStorage Phosphor
No digital memory
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Direct View Storage Tube
Two electron guns Primary electron gun draws the picture by knocking out electrons from the storage
grid, producing a positively charged pattern. Low speed electrons from the flood gun are attracted to the storage grid, and pass
through the positively charge pattern spots (past the collector grid) to hit the screen.
Once a picture is drawn it stays until erased by putting a charge over all of the storage grid so that the electrons hit all of the screen (producing a green flash on a green screen monitor).
Much cheaper then a regular random scan system did not require a built in CPU host computer was used to draw the image once
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1200-9600 baud serial
MOVE(ix,iy)DRAW(ix,iy)POINT(ix,iy)DASH(ix,iy,idash)
CS-321Dr. Mark L. Hornick
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Raster Scanning
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Video Display
Video graphics adapter Television monitor
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Early graphics adapters
Bus
CPU SystemMemory
Scan Converter
video, vga
Frame buffer
Pixel construction
• CPU constructs “virtual image” in System Memory • Scan converter reads virtual image and converts to video or vga signals