Computer
Graphics
and
Animation
,1. What is computer graphics?
Computer Graphics is part of drawing pictures on the computer screen with the help of the program. It is the use
of the computer to design, store, manipulate, and represent picturing output. It is made up of a number of pixels.
In other words, we can say that computer graphics is a rendering tool for the generation and manipulation of
images. It is the use of computers to create and manipulate pictures on display devices. It comprises software
techniques to create, store, modify, and represent pictures.
2. Describe the application of computer graphics.
Computer Graphics has numerous applications, some of which are listed below:
• Graphics user interfaces
• Computer-Aided Design
• Business presentation graphics
• Cartography
• Weather Maps
• Satellite Imaging
• Photo Enhancement
• Medical imaging
• Engineering drawings
• Typography
• Architecture
• Computer Art
• Training
• Entertainment
• Simulation and modeling
• Visualization
3. Explain different types of input devices available for operator interaction in detail.
Input devices are things we use to put information into a computer. The input device is a hardware device that
takes data from the user and sends it to the computer. It allows users to interact with computers. There are
different types of input devices available which are as follows:
• Text Input Devices are devices that take input in text format. Examples of these devices are:
a. The keyboard is the default input device used with computers. It is used to input text, and
characters, to pass commands, and to control the computer using special keys.
b. Optical Character Recognition (OCR) is the recognition of printed or written text characters by
computer.
• Pointing Input Devices are devices that point at specific options or areas on the screen. Examples of these
devices are:
a. A Mouse is a pointing device that controls the movement of the pointer on a computer screen.
There are 2 types of these, mechanical and optical. A mechanical mouse consists of a small ball
inside the body of the mouse which can rotate in any direction. An optical mouse uses light-
emitting diodes and photodiodes to detect the position of the device on the underlying surface.
These are more efficient as they don't have any moving parts into it.
b. Trackball is same as mouse. It has a ball located in the socket which contains sensors, that detect
the rotation of the ball.
c. Other examples of Pointing Input Devices are a Joystick, Touch Screen, TouchPad, Data Glove,
Graphic Tablets, Voice systems, etc.
• Image and Video Input Devices are devices that take input in image and video format. Examples of these
devices are:
a. Image Scanner is a digital device used to scan images, pictures, printed text, and objects and then
convert them to digital images. Image scanners are used in a variety of domestic and industrial
applications like design, reverse engineering, orthotics, gaming, and testing.
b. Digital Camera records and stores photographic images in digital form. Many current models are
also able to capture sound or video, in addition to still images.
c. Webcam is a small digital video camera directly or indirectly connected to a computer or
computer network.
, 4. Different between active & passive graphics devices?
Active Devices Passive devices
It is dynamic in nature. Control is provided to the user It is Static in nature. Control is not provided to the user
to manipulate graphics. to manipulate graphics. It works on already-written
instructions
It provides two-way communication, between the user It provides one-way communication, only through the
and the computer. computer.
High bandwidth user interaction with H/W devices. No interaction between the user and hardware
devices
Modern application Older Application
Facility available which supports 2D and 3D No facility available which supports 2D and 3D
transformation transformation
5. Explain display devices of computer graphics.
Graphical displays are generally of 2 types:
• Vector Display:
Vector displays generally display lines, specified by their endpoints. These systems operate by direct control
of the electron beam of the Cathode Ray Tube (CRT). Tektronics was the company that dominated the market
for vector displays. These are becoming increasingly rare due to the advent of low-cost raster display
technology. These must be periodically refreshed. The time required to refresh was proportional to the
complexity of the scene, therefore complex scenes can be impractical for vector displays. However, they have
certain advantages, such as the absence of aliasing. Aliasing is a jagged appearance of primitives as displayed
on raster devices. This phenomenon is also known as "jaggies", or sometimes "staircase effect". This problem
is resolved by various anti-aliasing techniques.
• Raster Display:
Raster displays, typically have an array of addressable dots called pixels, which can be individually set to a
particular color or intensity, which together form an image. These can be implemented by several
technologies. A raster image has a specific number of pixels. When you enlarge the image file without
changing the number of pixels, the image will look blurry. When you enlarge the file by adding more pixels,
pixels are added randomly throughout the image, rarely producing good results. When you enlarge vector
graphics, math formulas stay the same, rendering the same visual graphic no matter the size. Vector graphics
can be scaled to any size without losing quality. Currently most popular is the cathode ray tube, which can
implement both raster and vector displays.
6. Explain CRT.
The primary output device in the graphical system is a video monitor. CRT stands for Cathode Ray Tube. The
operation of CRT is very simple as follows:
• An electron gun emits a beam of electrons.
• Electron beam passes through focusing and deflection systems that direct it towards specified positions on
the phosphor-coated screen.
• When the beam hits the screen, the phosphor emits a small spot of light at each position contacted by the
electron beam.
• It redraws the picture by directing the electron beam back over the same screen points quickly.
Graphics
and
Animation
,1. What is computer graphics?
Computer Graphics is part of drawing pictures on the computer screen with the help of the program. It is the use
of the computer to design, store, manipulate, and represent picturing output. It is made up of a number of pixels.
In other words, we can say that computer graphics is a rendering tool for the generation and manipulation of
images. It is the use of computers to create and manipulate pictures on display devices. It comprises software
techniques to create, store, modify, and represent pictures.
2. Describe the application of computer graphics.
Computer Graphics has numerous applications, some of which are listed below:
• Graphics user interfaces
• Computer-Aided Design
• Business presentation graphics
• Cartography
• Weather Maps
• Satellite Imaging
• Photo Enhancement
• Medical imaging
• Engineering drawings
• Typography
• Architecture
• Computer Art
• Training
• Entertainment
• Simulation and modeling
• Visualization
3. Explain different types of input devices available for operator interaction in detail.
Input devices are things we use to put information into a computer. The input device is a hardware device that
takes data from the user and sends it to the computer. It allows users to interact with computers. There are
different types of input devices available which are as follows:
• Text Input Devices are devices that take input in text format. Examples of these devices are:
a. The keyboard is the default input device used with computers. It is used to input text, and
characters, to pass commands, and to control the computer using special keys.
b. Optical Character Recognition (OCR) is the recognition of printed or written text characters by
computer.
• Pointing Input Devices are devices that point at specific options or areas on the screen. Examples of these
devices are:
a. A Mouse is a pointing device that controls the movement of the pointer on a computer screen.
There are 2 types of these, mechanical and optical. A mechanical mouse consists of a small ball
inside the body of the mouse which can rotate in any direction. An optical mouse uses light-
emitting diodes and photodiodes to detect the position of the device on the underlying surface.
These are more efficient as they don't have any moving parts into it.
b. Trackball is same as mouse. It has a ball located in the socket which contains sensors, that detect
the rotation of the ball.
c. Other examples of Pointing Input Devices are a Joystick, Touch Screen, TouchPad, Data Glove,
Graphic Tablets, Voice systems, etc.
• Image and Video Input Devices are devices that take input in image and video format. Examples of these
devices are:
a. Image Scanner is a digital device used to scan images, pictures, printed text, and objects and then
convert them to digital images. Image scanners are used in a variety of domestic and industrial
applications like design, reverse engineering, orthotics, gaming, and testing.
b. Digital Camera records and stores photographic images in digital form. Many current models are
also able to capture sound or video, in addition to still images.
c. Webcam is a small digital video camera directly or indirectly connected to a computer or
computer network.
, 4. Different between active & passive graphics devices?
Active Devices Passive devices
It is dynamic in nature. Control is provided to the user It is Static in nature. Control is not provided to the user
to manipulate graphics. to manipulate graphics. It works on already-written
instructions
It provides two-way communication, between the user It provides one-way communication, only through the
and the computer. computer.
High bandwidth user interaction with H/W devices. No interaction between the user and hardware
devices
Modern application Older Application
Facility available which supports 2D and 3D No facility available which supports 2D and 3D
transformation transformation
5. Explain display devices of computer graphics.
Graphical displays are generally of 2 types:
• Vector Display:
Vector displays generally display lines, specified by their endpoints. These systems operate by direct control
of the electron beam of the Cathode Ray Tube (CRT). Tektronics was the company that dominated the market
for vector displays. These are becoming increasingly rare due to the advent of low-cost raster display
technology. These must be periodically refreshed. The time required to refresh was proportional to the
complexity of the scene, therefore complex scenes can be impractical for vector displays. However, they have
certain advantages, such as the absence of aliasing. Aliasing is a jagged appearance of primitives as displayed
on raster devices. This phenomenon is also known as "jaggies", or sometimes "staircase effect". This problem
is resolved by various anti-aliasing techniques.
• Raster Display:
Raster displays, typically have an array of addressable dots called pixels, which can be individually set to a
particular color or intensity, which together form an image. These can be implemented by several
technologies. A raster image has a specific number of pixels. When you enlarge the image file without
changing the number of pixels, the image will look blurry. When you enlarge the file by adding more pixels,
pixels are added randomly throughout the image, rarely producing good results. When you enlarge vector
graphics, math formulas stay the same, rendering the same visual graphic no matter the size. Vector graphics
can be scaled to any size without losing quality. Currently most popular is the cathode ray tube, which can
implement both raster and vector displays.
6. Explain CRT.
The primary output device in the graphical system is a video monitor. CRT stands for Cathode Ray Tube. The
operation of CRT is very simple as follows:
• An electron gun emits a beam of electrons.
• Electron beam passes through focusing and deflection systems that direct it towards specified positions on
the phosphor-coated screen.
• When the beam hits the screen, the phosphor emits a small spot of light at each position contacted by the
electron beam.
• It redraws the picture by directing the electron beam back over the same screen points quickly.
