- UNIT-I
~Representative Uses of Computer Graphics
~Classification of Application Development of Hardware and software for computer Graphics
~Overview, Scan:
~Converting Lines
~Scan Converting Circles
~Scan Converting Ellipses
~Display Technologies
~Raster-Scan Display System
~Video Controller
~Random-Scan Display processor
~Input Devices for Operator Interaction
~Image Scanners
~Working exposure on graphics tools like Dream Weaver, 3D Effects etc
~Clipping
~Southland- Cohen Algorithm
~Cyrus-Beck Algorithm
~Midpoint Subdivision Algorithm
~2D Transformation
~Homogeneous Coordinates and Matrix Representation of 2DTransformations
~composition of 2D Transformations
~The Window-to-Viewport
Transformations
~Multimedia Definition
~CD-ROM and the multimedia highway
~Computer Animation
(Design, types of animation, using different functions)
~CD-ROM and the multimedia highway
~Computer Animation
(Design, types of animation, using different functions)
~Uses of Multimedia
~Introduction to making multimedia –
~The stage of Project
~hardware & software requirements to make good multimedia skills
~Training opportunities in Multimedia Motivation for Multimedia usage
~Introduction to making multimedia –
~The stage of Project
~hardware & software requirements to make good multimedia skills
~Training opportunities in Multimedia Motivation for Multimedia usage
Display technology
Graphical displays are generally of two types:
vector displays and raster displays.
Vector displays
A vector show is a sort of show wherein an electron weapon is utilized to draw designs on the screen. Dissimilar to standard cathode beam tube (CRT) innovation utilized in TVs, in which level lines are attracted arrangement, a vector show just makes pictures on the screen were important, and skirts clear zones.
A vector show is otherwise called a vector screen.
A vector show is otherwise called a vector screen.
Cathode beam tube (CRT)
The standard PC screen (or TV screen) depends on the cathode beam tube (CRT). Basically, a light emission is produced, and examined over the inward surface of a glass tube. The inward surface of the cylinder is covered with a phosphor which emanates light when electrons strike it. The force of the discharged light from a point on the phosphor relies upon the quantity of electrons striking the phosphor.
The electron shaft is examined more than once over the phosphor surface, with the power of the pillar adjusted to create the necessary dim and light spots. In the event that the examining rate is sufficiently quick, the screen creates a consistent picture.
(TV pictures are redrawn 30 times each second; high quality screens are invigorated 60 times each second, or more.)
Distinctive phosphor materials radiate various hues, so it is pos-sible to build a shading show. Current CRT gadgets utilize a set of three of shaded phosphors — red, green, and blue — to deliver very worthy shading yield.
Generally, an electron firearm is utilized for every one of the essential hues, and a punctured lattice called a shadow veil is utilized to separate the electron shaft to a solitary phosphor "spot".
The nature of a shading CRT show relies upon the quantity of sets of three on the screen. There are various proportions of this "quality" — the quantity of lines (columns of dabs) and the "spot pitch" (separation between specks) being generally cited.
By and by, great screens can surpass 1200 lines and can have in excess of 1600 ternions for every line. The spot pitch can be not exactly 0.25 mm.
(Standard TV has 480 lines x 640 groups of three for every line, and is "entwined" — consistently line is redrawn every 1/60th of a second, for a full invigorate pace of 1/30th of a second.)
A "standard" 17-inch screen (16 inches visible) can have particulars as follows:
0.25mm dab pitch invigorate rate 48–120 Hz
1024 x 768 goals at 65 Hz
1600 x 1200 goals at 65 Hz
A very good quality screen (24 inches) can have a spot pitch of 0.22 mm, and goals of 2048 x 1536 at > 60Hz.
Liquid Crystal Display (LCD) technology
Liquid crystals are liquids with long organic molecules that can polarize light. When an electric field is applied, the molecu- lar alignment (and consequently the direction of polarization) changes.
An LCD is a “sandwich” of different layer
The reflective layer is just a mirror. The two polarizing lay-ers permits just light that is energized a suitable way to go through. The two layers of framework wires permit a particular voltage to be applied to a specific piece of the fluid precious stone layer.
At the point when no electric field is applied, the fluid gems change the extremity of episode light by 90◦. (The material science of this are beyond the extent of this course.) Therefore, the light will get ap-
fittingly turned to go in through the vertical polarizer, through the fluid precious stone layer, through the flat polarizer, reflect, and afterward retreat once more.
At the point when an electric field is applied, the fluid precious stones don't change the extremity of the episode light. Subsequently, no light will be reflected out of the LCD at the purpose of applied voltage and a dull spot will show up in the presentation.
• Different "shades of dim" can be gotten by shifting the voltage over the anodes.
• Liquid precious stones can be shaded to deliver a shading show by including shading channels.
• LCDs for PC shows are typically illuminated.
• One issue with certain LCDs is that it takes around 1/4 of a second (250 ms.) to change state. This leaves "phantoms" on the presentation for a small amount of a second.
• This issue can be wiped out by adding a transistor enhancer to every pixel, so the voltage can be exchanged all the more quickly (TFT — slight film transistors). TFT shows are increasingly costly to make yet have the accompanying favorable circumstances:
– Faster reaction time (25ms)
– More shades of dark
– Higher differentiate proportion
– Displays littler and lighter
• Both kinds of LCD devour far less force than a CRT (about 75% less), and are in this manner only utilized in battery-worked gadgets.
Plasma technology
Plasma
displays provide an alternative to CRT’s and
LCD’s. Plasma displays consist of a
matrix of fluorescent bulbs
As a voltage is applied to every bulb, the blend of honorable gases inside the bulb gets ionized and discharges bright light. The UV photons strike a phosphor covering on the bulb that makes obvious light be discharged. Distinctive hued phosphors permit diverse shaded pixels to be delivered.
In contrast with CRT's plasma shows are very thin. Also, plasma shows give a light source at every pixel and are in this manner more brilliant and show higher complexity than LCD shows. They additionally have bigger review edges than LCDs — the picture
looks great from a wide assortment of edges.
In any case, both LCDs and CRTs are really ready to accomplish higher goals then plasma shows. LCD's likewise devoured less force and are thought to last more. Plasma shows have generally had a "consume in" issue, yet this has been lightened as of late.
All the raster advances make them thing in like manner — they have a limited number of normally dispersed focuses which can be set to some shading.
Graphics cards
Graphics cards have taken on much of
the responsibility for video output from the CPU. The most basic graphics card
contains a frame buffer and circuitry to convert
the color values
into the voltages or currents
used by the display.
Modern
graphics cards have powerful
graphics processors that handle many of the rendering functions and image transformations directly in their circuitry. (We will describe many of these functions later.)
A
typical graphics card might look as follows:
Modern graphics cards contain much more memory than is required for
the frame buffer.
Typically, some of this memory is used to store a description of the scene, (information about
primitives, vertices, colors, etc.) which is interpreted by the graphics processor.
Another memory is used
to store textures and other bitmapsRaster-Scan Displays
Raster Scan Displays are the most normal kind of illustrations screen which utilizes CRT. It depends on TV innovation. In raster filter framework electron pillar clears over the screen, through and through covering one line at a time.An example of an enlightened example of spots is made by turning shaft force on and off as it moves over each line. A memory territory called revive cushion or casing cradle stores picture definition. This memory territory holds force esteems for all screen focuses. Put away power esteems are reestablished from outline cushion and painted on-screen taking one line at a time. Each screen point is alluded to as pixels.
In raster filter frameworks reviving is done at a pace of 60-80 edges for each second. Invigorate rates are additionally some of the time depicted in units of cycles every second/Hertz (Hz). Toward the finish of each output line, electron shaft starts to show the next sweep line subsequent to coming back to the left half of the screen. The arrival to one side of the screen after the revive of each sweep line is known as even following of electron bar. Toward the finish of each edge, the electron pillar comes back to the upper left corner and starts the following edge.
Raster-Scan Display Processor:
A significant capacity of the show process is to digitize an image definition given in an application program into a lot of pixel-power esteems for capacity in reviving cradle. This procedure is alluded to as output change. The motivation behind presentation processors is to mitigate the CPU from illustrations occupations.
Show processors can perform different undertakings like: making distinctive line styles, showing shading territories, and so forth. Ordinarily show processors are used to interface input gadgets, for example, mouse, joysticks.
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