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**Note**Institute:
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Sri Adi Chunchanagiri Women's College
**Course:
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B.Tech
**Specialization:
**Information Technology Engineering**Views:
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Computer Graphics
Computer graphics are graphics created using computers and the representation of image data by
a computer specifically with help from specialized graphic hardware and software. Formally we
can say that Computer graphics is creation, manipulation and storage of geometric objects
(modeling) and their images (Rendering).
The field of computer graphics developed with the emergence of computer graphics hardware.
Today computer graphics is use in almost every field. Many powerful tools have been developed
to visualize data. Computer graphics field become more popular when companies started using it
in video games. Today it is a multibillion dollar industry and main driving force behind the
computer graphics development. Some common applications areas are as following:
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Computer Aided Design (CAD)
Presentation Graphics
3d Animation
Education and training
Graphical User Interfaces
Computer Aided Design:
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Used in design of buildings, automobiles, aircraft and many other product
Use to make virtual reality system.
Presentation Graphics:
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Commonly used to summarize financial ,statistical data
Use to generate slides
3d Animation:
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Used heavily in the movie industry by companies such as Pixar, DresmsWorks
To add special effects in games and movies.
Education and training:
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Computer generated models of physical systems
Medical Visualization
3D MRI
Dental and bone scans
Stimulators for training of pilots etc.
Graphical User Interfaces:
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It is used to make graphical user interfaces objects like buttons, icons and other
components

Application of Computer Graphics
Computer Graphics has numerous applications, some of which are listed below −
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Computer graphics user interfaces (GUIs) − A graphic, mouse-oriented paradigm
which allows the user to interact with a computer.
Business presentation graphics − "A picture is worth a thousand words".
Cartography − Drawing maps.
Weather Maps − Real-time mapping, symbolic representations.
Satellite Imaging − Geodesic images.
Photo Enhancement − Sharpening blurred photos.
Medical imaging − MRIs, CAT scans, etc. - Non-invasive internal examination.
Engineering drawings − mechanical, electrical, civil, etc. - Replacing the blueprints of
the past.
Typography − The use of character images in publishing - replacing the hard type of the
past.
Architecture − Construction plans, exterior sketches - replacing the blueprints and hand
drawings of the past.
Art − Computers provide a new medium for artists.
Training − Flight simulators, computer aided instruction, etc.
Entertainment − Movies and games.
Simulation and modeling − Replacing physical modeling and enactments
Transformation means changing some graphics into something else by applying rules. We can
have various types of transformations such as translation, scaling up or down, rotation, shearing,
etc. When a transformation takes place on a 2D plane, it is called 2D transformation.
Transformations play an important role in computer graphics to reposition the graphics on the
screen and change their size or orientation.
Homogenous Coordinates
To perform a sequence of transformation such as translation followed by rotation and scaling, we
need to follow a sequential process −
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Translation
A translation moves an object to a different position on the screen. You can translate a
point in 2D by adding translation coordinate (tx, ty) to the original coordinate (X, Y) to
get the new coordinate (X’, Y’).

Rotation
In rotation, we rotate the object at particular angle θ (theta) from its origin. From the following
figure, we can see that the point P(X, Y) is located at angle φ from the horizontal X coordinate
with distance r from the origin.
Let us suppose you want to rotate it at the angle θ. After rotating it to a new location, you will get
a new point P’ (X’, Y’).
Scaling
To change the size of an object, scaling transformation is used. In the scaling process, you either
expand or compress the dimensions of the object. Scaling can be achieved by multiplying the
original coordinates of the object with the scaling factor to get the desired result.
Where S is the scaling matrix. The scaling process is shown in the following figure.
If we provide values less than 1 to the scaling factor S, then we can reduce the size of the object.
If we provide values greater than 1, then we can increase the size of the object.
Reflection
Reflection is the mirror image of original object. In other words, we can say that it is a rotation
operation with 180°. In reflection transformation, the size of the object does not change.

The following figures show reflections with respect to X and Y axes, and about the origin
respectively.
Shear
A transformation that slants the shape of an object is called the shear transformation. There are
two shear transformations X-Shear and Y-Shear. One shifts X coordinates values and other
shifts Y coordinate values. However; in both the cases only one coordinate changes its
coordinates and other preserves its values. Shearing is also termed as Skewing.
X-Shear
The X-Shear preserves the Y coordinate and changes are made to X coordinates, which causes
the vertical lines to tilt right or left as shown in below figure.
Y-Shear
The Y-Shear preserves the X coordinates and changes the Y coordinates which causes the
horizontal lines to transform into lines which slopes up or down as shown in the following
figure.

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