Chapter-2 Overview of Graphics Systems Topics: Topics: Video-display system Video-display system...
-
Upload
deirdre-mcdaniel -
Category
Documents
-
view
220 -
download
2
Transcript of Chapter-2 Overview of Graphics Systems Topics: Topics: Video-display system Video-display system...
![Page 1: Chapter-2 Overview of Graphics Systems Topics: Topics: Video-display system Video-display system Rater Scan systems Rater Scan systems Random scan systems.](https://reader038.fdocuments.us/reader038/viewer/2022103005/56649d8b5503460f94a723ac/html5/thumbnails/1.jpg)
Chapter-2Chapter-2Overview of Graphics SystemsOverview of Graphics Systems
Topics:Topics:
Video-display systemVideo-display system Rater Scan systemsRater Scan systems Random scan systemsRandom scan systems Graphic monitors and workstationsGraphic monitors and workstations Input devicesInput devices Hard-copy devicesHard-copy devices Graphics SoftwareGraphics Software
![Page 2: Chapter-2 Overview of Graphics Systems Topics: Topics: Video-display system Video-display system Rater Scan systems Rater Scan systems Random scan systems.](https://reader038.fdocuments.us/reader038/viewer/2022103005/56649d8b5503460f94a723ac/html5/thumbnails/2.jpg)
Video-Display DevicesVideo-Display DevicesRefresh Cathode-Ray TunesRefresh Cathode-Ray Tunes
Fig.2-2 Basic design of a magnetic-deflection CRT
![Page 3: Chapter-2 Overview of Graphics Systems Topics: Topics: Video-display system Video-display system Rater Scan systems Rater Scan systems Random scan systems.](https://reader038.fdocuments.us/reader038/viewer/2022103005/56649d8b5503460f94a723ac/html5/thumbnails/3.jpg)
Video-Display DevicesVideo-Display DevicesRefresh Cathode-Ray TunesRefresh Cathode-Ray Tunes
Fig.2-3 Operation of an electron gun with an accelerating anode.
![Page 4: Chapter-2 Overview of Graphics Systems Topics: Topics: Video-display system Video-display system Rater Scan systems Rater Scan systems Random scan systems.](https://reader038.fdocuments.us/reader038/viewer/2022103005/56649d8b5503460f94a723ac/html5/thumbnails/4.jpg)
Video-Display DevicesVideo-Display DevicesRefresh Cathode-Ray TunesRefresh Cathode-Ray Tunes
Fig.2-4 Electrostatic deflection of the electron beam in a CRT
![Page 5: Chapter-2 Overview of Graphics Systems Topics: Topics: Video-display system Video-display system Rater Scan systems Rater Scan systems Random scan systems.](https://reader038.fdocuments.us/reader038/viewer/2022103005/56649d8b5503460f94a723ac/html5/thumbnails/5.jpg)
Video-Display DevicesVideo-Display DevicesIllumination of phosphor spots on back of Illumination of phosphor spots on back of
CRTCRT
![Page 6: Chapter-2 Overview of Graphics Systems Topics: Topics: Video-display system Video-display system Rater Scan systems Rater Scan systems Random scan systems.](https://reader038.fdocuments.us/reader038/viewer/2022103005/56649d8b5503460f94a723ac/html5/thumbnails/6.jpg)
Video-Display DevicesVideo-Display DevicesFig.2-7 A raster –scan system displays an object as Fig.2-7 A raster –scan system displays an object as
a set of discrete points across each scan line.a set of discrete points across each scan line.
![Page 7: Chapter-2 Overview of Graphics Systems Topics: Topics: Video-display system Video-display system Rater Scan systems Rater Scan systems Random scan systems.](https://reader038.fdocuments.us/reader038/viewer/2022103005/56649d8b5503460f94a723ac/html5/thumbnails/7.jpg)
Video-Display DevicesVideo-Display DevicesNote at the Interlace mechanism of display: display the even
lines in1/60 of a second and then display the odd lines in next 1/60
seconds.
![Page 8: Chapter-2 Overview of Graphics Systems Topics: Topics: Video-display system Video-display system Rater Scan systems Rater Scan systems Random scan systems.](https://reader038.fdocuments.us/reader038/viewer/2022103005/56649d8b5503460f94a723ac/html5/thumbnails/8.jpg)
Video-Display DevicesVideo-Display DevicesFig.2-9 A random-scan system draws the component lines of Fig.2-9 A random-scan system draws the component lines of
an object in any order specified.an object in any order specified.
![Page 9: Chapter-2 Overview of Graphics Systems Topics: Topics: Video-display system Video-display system Rater Scan systems Rater Scan systems Random scan systems.](https://reader038.fdocuments.us/reader038/viewer/2022103005/56649d8b5503460f94a723ac/html5/thumbnails/9.jpg)
Video-Display DevicesVideo-Display Devices
Fig.2-10 Operation of a delta-delta, shadow-mask CRT. Three Fig.2-10 Operation of a delta-delta, shadow-mask CRT. Three electron guns, aligned with the triangular color-dot patterns electron guns, aligned with the triangular color-dot patterns
on the screen, on the screen, are directed to each dot triangle by a shadow mask.are directed to each dot triangle by a shadow mask.
![Page 10: Chapter-2 Overview of Graphics Systems Topics: Topics: Video-display system Video-display system Rater Scan systems Rater Scan systems Random scan systems.](https://reader038.fdocuments.us/reader038/viewer/2022103005/56649d8b5503460f94a723ac/html5/thumbnails/10.jpg)
Flat panel displaysFlat panel displaysFig.2-11 Basic design of a plasma-panel display Fig.2-11 Basic design of a plasma-panel display
device.device.
Applying voltages to a pair of horizontal and vertical conductors causes the gas at the intersection of two conductors to break down into a glowing
plasma of electron and ions.
![Page 11: Chapter-2 Overview of Graphics Systems Topics: Topics: Video-display system Video-display system Rater Scan systems Rater Scan systems Random scan systems.](https://reader038.fdocuments.us/reader038/viewer/2022103005/56649d8b5503460f94a723ac/html5/thumbnails/11.jpg)
Flat panel displaysFlat panel displaysA plasma-panel display with a resolution of 2048 x A plasma-panel display with a resolution of 2048 x
2048 and a screen diameter of 1.5 meters.2048 and a screen diameter of 1.5 meters.
![Page 12: Chapter-2 Overview of Graphics Systems Topics: Topics: Video-display system Video-display system Rater Scan systems Rater Scan systems Random scan systems.](https://reader038.fdocuments.us/reader038/viewer/2022103005/56649d8b5503460f94a723ac/html5/thumbnails/12.jpg)
Flat panel displaysFlat panel displaysBasic design of a thin-film electro-luminescentBasic design of a thin-film electro-luminescent
display device. display device.
![Page 13: Chapter-2 Overview of Graphics Systems Topics: Topics: Video-display system Video-display system Rater Scan systems Rater Scan systems Random scan systems.](https://reader038.fdocuments.us/reader038/viewer/2022103005/56649d8b5503460f94a723ac/html5/thumbnails/13.jpg)
Liquid-crystal displays (LCD)Liquid-crystal displays (LCD)Laptops use LCD display mechanism with different Laptops use LCD display mechanism with different
resolutions and different number of colors.resolutions and different number of colors.
![Page 14: Chapter-2 Overview of Graphics Systems Topics: Topics: Video-display system Video-display system Rater Scan systems Rater Scan systems Random scan systems.](https://reader038.fdocuments.us/reader038/viewer/2022103005/56649d8b5503460f94a723ac/html5/thumbnails/14.jpg)
How a Liquid-crystal displays (LCD) How a Liquid-crystal displays (LCD) works.works.
By twisting the LCD Nematics, the polarized light passed By twisting the LCD Nematics, the polarized light passed through the horizontal conductor will twist and pass through through the horizontal conductor will twist and pass through
the vertical conductor.the vertical conductor.
This is how one pixelBecomes visible.
To turn off a pixel, theLCD Nematics will beForced to becomeParallel.
This is done by applyingA voltage to bothHorizontal and verticalconductors.
The screen is refreshedin the rate of 60 frames per secondAs in emissive devices.
![Page 15: Chapter-2 Overview of Graphics Systems Topics: Topics: Video-display system Video-display system Rater Scan systems Rater Scan systems Random scan systems.](https://reader038.fdocuments.us/reader038/viewer/2022103005/56649d8b5503460f94a723ac/html5/thumbnails/15.jpg)
Stereoscopic and Virtual-Reality Stereoscopic and Virtual-Reality SystemsSystems
Fig.2-19 Viewing a stereoscopic projection.Fig.2-19 Viewing a stereoscopic projection.
![Page 16: Chapter-2 Overview of Graphics Systems Topics: Topics: Video-display system Video-display system Rater Scan systems Rater Scan systems Random scan systems.](https://reader038.fdocuments.us/reader038/viewer/2022103005/56649d8b5503460f94a723ac/html5/thumbnails/16.jpg)
Stereoscopic and Virtual-Reality Stereoscopic and Virtual-Reality SystemsSystems
Fig.2-20 A stereoscopic viewing pair.Fig.2-20 A stereoscopic viewing pair.
![Page 17: Chapter-2 Overview of Graphics Systems Topics: Topics: Video-display system Video-display system Rater Scan systems Rater Scan systems Random scan systems.](https://reader038.fdocuments.us/reader038/viewer/2022103005/56649d8b5503460f94a723ac/html5/thumbnails/17.jpg)
Stereoscopic and Virtual-Reality Stereoscopic and Virtual-Reality SystemsSystems
Fig.2-21 Glasses for viewing a stereoscopic scene Fig.2-21 Glasses for viewing a stereoscopic scene and an infrared synchronizing emitter.and an infrared synchronizing emitter.
![Page 18: Chapter-2 Overview of Graphics Systems Topics: Topics: Video-display system Video-display system Rater Scan systems Rater Scan systems Random scan systems.](https://reader038.fdocuments.us/reader038/viewer/2022103005/56649d8b5503460f94a723ac/html5/thumbnails/18.jpg)
Stereoscopic and Virtual-Reality Stereoscopic and Virtual-Reality SystemsSystems
Fig.2-22 A headset used in virtual-reality systemFig.2-22 A headset used in virtual-reality system
![Page 19: Chapter-2 Overview of Graphics Systems Topics: Topics: Video-display system Video-display system Rater Scan systems Rater Scan systems Random scan systems.](https://reader038.fdocuments.us/reader038/viewer/2022103005/56649d8b5503460f94a723ac/html5/thumbnails/19.jpg)
Interacting with a virtual-reality Interacting with a virtual-reality environment.environment.
Use of head-set, data gloves and a set of cords to Use of head-set, data gloves and a set of cords to transfer the data to a host computer.transfer the data to a host computer.
![Page 20: Chapter-2 Overview of Graphics Systems Topics: Topics: Video-display system Video-display system Rater Scan systems Rater Scan systems Random scan systems.](https://reader038.fdocuments.us/reader038/viewer/2022103005/56649d8b5503460f94a723ac/html5/thumbnails/20.jpg)
Fig.2-24 An ultrasound tracking device Fig.2-24 An ultrasound tracking device used with stereoscopic glass to track head used with stereoscopic glass to track head
position.position.
![Page 21: Chapter-2 Overview of Graphics Systems Topics: Topics: Video-display system Video-display system Rater Scan systems Rater Scan systems Random scan systems.](https://reader038.fdocuments.us/reader038/viewer/2022103005/56649d8b5503460f94a723ac/html5/thumbnails/21.jpg)
Raster-scan systemRaster-scan systemFig.2-25 The architecture of a simple raster graphics Fig.2-25 The architecture of a simple raster graphics
system.system.
![Page 22: Chapter-2 Overview of Graphics Systems Topics: Topics: Video-display system Video-display system Rater Scan systems Rater Scan systems Random scan systems.](https://reader038.fdocuments.us/reader038/viewer/2022103005/56649d8b5503460f94a723ac/html5/thumbnails/22.jpg)
Raster-scan systemRaster-scan systemFig.2-26 Architecture of a raster system with a fixed portion Fig.2-26 Architecture of a raster system with a fixed portion
of the system memory reserved for the frame buffer.of the system memory reserved for the frame buffer.
![Page 23: Chapter-2 Overview of Graphics Systems Topics: Topics: Video-display system Video-display system Rater Scan systems Rater Scan systems Random scan systems.](https://reader038.fdocuments.us/reader038/viewer/2022103005/56649d8b5503460f94a723ac/html5/thumbnails/23.jpg)
Raster-scan systemRaster-scan system
![Page 24: Chapter-2 Overview of Graphics Systems Topics: Topics: Video-display system Video-display system Rater Scan systems Rater Scan systems Random scan systems.](https://reader038.fdocuments.us/reader038/viewer/2022103005/56649d8b5503460f94a723ac/html5/thumbnails/24.jpg)
Raster-scan systemRaster-scan system
Fig.2-28 Basic video-controller refresh operations.
![Page 25: Chapter-2 Overview of Graphics Systems Topics: Topics: Video-display system Video-display system Rater Scan systems Rater Scan systems Random scan systems.](https://reader038.fdocuments.us/reader038/viewer/2022103005/56649d8b5503460f94a723ac/html5/thumbnails/25.jpg)
Raster-scan systemRaster-scan system
Fig. 2-29 Architecture of a raster-graphics system with a display processor.
![Page 26: Chapter-2 Overview of Graphics Systems Topics: Topics: Video-display system Video-display system Rater Scan systems Rater Scan systems Random scan systems.](https://reader038.fdocuments.us/reader038/viewer/2022103005/56649d8b5503460f94a723ac/html5/thumbnails/26.jpg)
How characters are displayed on aHow characters are displayed on aRaster-scan systemRaster-scan system
Limits in size, font type, etc.Possibilities to save fonts of differentSizes without the need to save a large bitmap.
![Page 27: Chapter-2 Overview of Graphics Systems Topics: Topics: Video-display system Video-display system Rater Scan systems Rater Scan systems Random scan systems.](https://reader038.fdocuments.us/reader038/viewer/2022103005/56649d8b5503460f94a723ac/html5/thumbnails/27.jpg)
Random-scan systemsRandom-scan systems
Fig.2-32 Architecture of a simple random-scan system.
![Page 28: Chapter-2 Overview of Graphics Systems Topics: Topics: Video-display system Video-display system Rater Scan systems Rater Scan systems Random scan systems.](https://reader038.fdocuments.us/reader038/viewer/2022103005/56649d8b5503460f94a723ac/html5/thumbnails/28.jpg)
Graphics monitors and work-Graphics monitors and work-stationsstations
Fig.2-35 A very high-resolution (2560 x 2048) color monitor for Air traffic control application.
![Page 29: Chapter-2 Overview of Graphics Systems Topics: Topics: Video-display system Video-display system Rater Scan systems Rater Scan systems Random scan systems.](https://reader038.fdocuments.us/reader038/viewer/2022103005/56649d8b5503460f94a723ac/html5/thumbnails/29.jpg)
Graphics monitors, A Media-WallGraphics monitors, A Media-Wall
Fig.2-36 The Media-Wall: A multi-screen display system. An image displayed on a 3-by-3 array of monitors.
Applications in Airports, and places that we need to have live announcements.
![Page 30: Chapter-2 Overview of Graphics Systems Topics: Topics: Video-display system Video-display system Rater Scan systems Rater Scan systems Random scan systems.](https://reader038.fdocuments.us/reader038/viewer/2022103005/56649d8b5503460f94a723ac/html5/thumbnails/30.jpg)
Graphics monitors and work-Graphics monitors and work-stationsstations
![Page 31: Chapter-2 Overview of Graphics Systems Topics: Topics: Video-display system Video-display system Rater Scan systems Rater Scan systems Random scan systems.](https://reader038.fdocuments.us/reader038/viewer/2022103005/56649d8b5503460f94a723ac/html5/thumbnails/31.jpg)
Multiple work-stations for a CAD Multiple work-stations for a CAD group.group.
![Page 32: Chapter-2 Overview of Graphics Systems Topics: Topics: Video-display system Video-display system Rater Scan systems Rater Scan systems Random scan systems.](https://reader038.fdocuments.us/reader038/viewer/2022103005/56649d8b5503460f94a723ac/html5/thumbnails/32.jpg)
An artist’s work-station, featuring a color raster An artist’s work-station, featuring a color raster monitor, graphic tablet with hand cursor, a light monitor, graphic tablet with hand cursor, a light
tablet.tablet.
![Page 33: Chapter-2 Overview of Graphics Systems Topics: Topics: Video-display system Video-display system Rater Scan systems Rater Scan systems Random scan systems.](https://reader038.fdocuments.us/reader038/viewer/2022103005/56649d8b5503460f94a723ac/html5/thumbnails/33.jpg)
Fig.2-42, Z mouse is used to displace Fig.2-42, Z mouse is used to displace objects in 3D space.objects in 3D space.
The Z mouse features 3 buttons, a mouse ball underneath,
a thumbwheel on the side, and a track ball on top.
![Page 34: Chapter-2 Overview of Graphics Systems Topics: Topics: Video-display system Video-display system Rater Scan systems Rater Scan systems Random scan systems.](https://reader038.fdocuments.us/reader038/viewer/2022103005/56649d8b5503460f94a723ac/html5/thumbnails/34.jpg)
Digitizers.Digitizers.Fig.2-46, The Summa-Sketch III desktop tablet with Fig.2-46, The Summa-Sketch III desktop tablet with
a 16 button hand cursor.a 16 button hand cursor.
![Page 35: Chapter-2 Overview of Graphics Systems Topics: Topics: Video-display system Video-display system Rater Scan systems Rater Scan systems Random scan systems.](https://reader038.fdocuments.us/reader038/viewer/2022103005/56649d8b5503460f94a723ac/html5/thumbnails/35.jpg)
Digitizers.Digitizers.The Microgrid III tablet with 16 button hand cursor, The Microgrid III tablet with 16 button hand cursor,
designed for digitizing larger drawings.designed for digitizing larger drawings.
![Page 36: Chapter-2 Overview of Graphics Systems Topics: Topics: Video-display system Video-display system Rater Scan systems Rater Scan systems Random scan systems.](https://reader038.fdocuments.us/reader038/viewer/2022103005/56649d8b5503460f94a723ac/html5/thumbnails/36.jpg)
Digitizers.Digitizers.Fig.2-48 The NotePad desktop tablet with stylus.Fig.2-48 The NotePad desktop tablet with stylus.
This devise is used forOn line signature input,On line handwriting input
And On-line drawing inputto a PC.
Some models of it can sense pressure, speed,and the direction ofpressure.
This is a perfect devisefor on line signature recognition.
![Page 37: Chapter-2 Overview of Graphics Systems Topics: Topics: Video-display system Video-display system Rater Scan systems Rater Scan systems Random scan systems.](https://reader038.fdocuments.us/reader038/viewer/2022103005/56649d8b5503460f94a723ac/html5/thumbnails/37.jpg)
Digitizers.Digitizers.
Fig.2-49 An artist’s digitizer system, with a pressure sensitive Cordless stylus.
![Page 38: Chapter-2 Overview of Graphics Systems Topics: Topics: Video-display system Video-display system Rater Scan systems Rater Scan systems Random scan systems.](https://reader038.fdocuments.us/reader038/viewer/2022103005/56649d8b5503460f94a723ac/html5/thumbnails/38.jpg)
Digitizers.Digitizers.Fig.2-50 A 3D digitizing system for use with Fig.2-50 A 3D digitizing system for use with
Apple Macintosh computers.Apple Macintosh computers.
![Page 39: Chapter-2 Overview of Graphics Systems Topics: Topics: Video-display system Video-display system Rater Scan systems Rater Scan systems Random scan systems.](https://reader038.fdocuments.us/reader038/viewer/2022103005/56649d8b5503460f94a723ac/html5/thumbnails/39.jpg)
Image ScannersImage ScannersFig.2-52 (Right) Drum scanner with a selectable Fig.2-52 (Right) Drum scanner with a selectable
resolution from 50 to 4000 dots per inch.resolution from 50 to 4000 dots per inch.
![Page 40: Chapter-2 Overview of Graphics Systems Topics: Topics: Video-display system Video-display system Rater Scan systems Rater Scan systems Random scan systems.](https://reader038.fdocuments.us/reader038/viewer/2022103005/56649d8b5503460f94a723ac/html5/thumbnails/40.jpg)
ScannerScannerFig. 2-53 A large floor-model scanner used to scan Fig. 2-53 A large floor-model scanner used to scan
architectural and engineering drawings up to architectural and engineering drawings up to 40 inches wide and 100 feet long.40 inches wide and 100 feet long.
![Page 41: Chapter-2 Overview of Graphics Systems Topics: Topics: Video-display system Video-display system Rater Scan systems Rater Scan systems Random scan systems.](https://reader038.fdocuments.us/reader038/viewer/2022103005/56649d8b5503460f94a723ac/html5/thumbnails/41.jpg)
Touch ScreensTouch ScreensFig. 2-54 Plasma panels with touch screens.Fig. 2-54 Plasma panels with touch screens.
![Page 42: Chapter-2 Overview of Graphics Systems Topics: Topics: Video-display system Video-display system Rater Scan systems Rater Scan systems Random scan systems.](https://reader038.fdocuments.us/reader038/viewer/2022103005/56649d8b5503460f94a723ac/html5/thumbnails/42.jpg)
How does a touch screen works.How does a touch screen works.
An optical touch panel, showing the arrangement of infrared LED units and detectors around the edges of
the frame.
![Page 43: Chapter-2 Overview of Graphics Systems Topics: Topics: Video-display system Video-display system Rater Scan systems Rater Scan systems Random scan systems.](https://reader038.fdocuments.us/reader038/viewer/2022103005/56649d8b5503460f94a723ac/html5/thumbnails/43.jpg)
Light PensLight Pens
Fig.2-56 A light pen activated with a button switch.
![Page 44: Chapter-2 Overview of Graphics Systems Topics: Topics: Video-display system Video-display system Rater Scan systems Rater Scan systems Random scan systems.](https://reader038.fdocuments.us/reader038/viewer/2022103005/56649d8b5503460f94a723ac/html5/thumbnails/44.jpg)
A speech-recognition systemA speech-recognition system
![Page 45: Chapter-2 Overview of Graphics Systems Topics: Topics: Video-display system Video-display system Rater Scan systems Rater Scan systems Random scan systems.](https://reader038.fdocuments.us/reader038/viewer/2022103005/56649d8b5503460f94a723ac/html5/thumbnails/45.jpg)
Hard copy devicesHard copy devicesA picture generated on a dot-matrix printer.A picture generated on a dot-matrix printer.
Note how the density of the dot patterns can be varied to Note how the density of the dot patterns can be varied to produce light and dark areas.produce light and dark areas.
![Page 46: Chapter-2 Overview of Graphics Systems Topics: Topics: Video-display system Video-display system Rater Scan systems Rater Scan systems Random scan systems.](https://reader038.fdocuments.us/reader038/viewer/2022103005/56649d8b5503460f94a723ac/html5/thumbnails/46.jpg)
Hard copy devicesHard copy devices
Fig.2-61 Floor model, ink-jet color printers that use variable dot size to achieve an equivalent resolution of 1500 to 1800 dots per inch.
![Page 47: Chapter-2 Overview of Graphics Systems Topics: Topics: Video-display system Video-display system Rater Scan systems Rater Scan systems Random scan systems.](https://reader038.fdocuments.us/reader038/viewer/2022103005/56649d8b5503460f94a723ac/html5/thumbnails/47.jpg)
Hard copy devices used to print Hard copy devices used to print large posterslarge posters
An electrostatic printer that can display 400 dots per inch.
![Page 48: Chapter-2 Overview of Graphics Systems Topics: Topics: Video-display system Video-display system Rater Scan systems Rater Scan systems Random scan systems.](https://reader038.fdocuments.us/reader038/viewer/2022103005/56649d8b5503460f94a723ac/html5/thumbnails/48.jpg)
Pen PlottersPen Plotters
Fig.2-63, A desk-top pen plotter with a resolution of 0.025 mm.
![Page 49: Chapter-2 Overview of Graphics Systems Topics: Topics: Video-display system Video-display system Rater Scan systems Rater Scan systems Random scan systems.](https://reader038.fdocuments.us/reader038/viewer/2022103005/56649d8b5503460f94a723ac/html5/thumbnails/49.jpg)
Pen PlottersPen Plotters
Fig.2-64 A large, roll-feed pen plotter with automatic multicolor 8-pen charger and a resolution of 0.0127 mm.
![Page 50: Chapter-2 Overview of Graphics Systems Topics: Topics: Video-display system Video-display system Rater Scan systems Rater Scan systems Random scan systems.](https://reader038.fdocuments.us/reader038/viewer/2022103005/56649d8b5503460f94a723ac/html5/thumbnails/50.jpg)
Graphics Software,Graphics Software,Coordinate representation. Note at different levels of Coordinate representation. Note at different levels of
transformation before an object is actually displayed on transformation before an object is actually displayed on monitor.monitor.