What is Computer Graphics?
The
meaning of the term Graphics is Graphical Tricks. Every image or picture is in fact a graph and when different
mathematical tricks are used to manipulate some change in its properties like
shape, size, motion etc., through the help of computers then, the
representation is nothing but computer graphics, so we can say that “Computer
Graphics refers to any sketch, drawing, special artwork or other material generated
with the help of computer to pictorially depict an object or a process or otherwise
convey information, as a supplement to or instead of written descriptions”.
What is 2D and 3D graphics?
2D:
-
2D is used to create flat digital images.
- X and Y horizontal and vertical axis are used in 2D.
- 2D graphics are used for printing and drawing applications.
- 2D graphics are vector based graphics.
- X and Y horizontal and vertical axis are used in 2D.
- 2D graphics are used for printing and drawing applications.
- 2D graphics are vector based graphics.
3D:
-
3D graphics represents 3 dimensional representations of geometric data, such as
length, breadth and depth.
- 3D graphics falls into 3 categories:
1.
3D modeling – the process of forming computer model of an object.
2. Layout and Animation – movement and placing and object in a scene are known as layout and animation.
3. 3D rendering – computer calculations that are based on light placement, surface types generate an image.
2. Layout and Animation – movement and placing and object in a scene are known as layout and animation.
3. 3D rendering – computer calculations that are based on light placement, surface types generate an image.
What is the difference between vector and
raster graphics?
Raster
Graphics:
-
Raster graphics are composed of pixels.
- Raster graphic is an array of multicolor pixels those form an image.
- Raster graphic blocks images because each pixel increases the size of the image.
- Raster graphic is an array of multicolor pixels those form an image.
- Raster graphic blocks images because each pixel increases the size of the image.
Vector
Graphics:
-
Vector graphics are generated with paths.
- Every path comprises of lines that may be straight or curved.
- Vector graphics can be scaled without losing the image quality.
- Every path comprises of lines that may be straight or curved.
- Vector graphics can be scaled without losing the image quality.
What is Transformation?
In many cases a complex
picture can always be treated as a
combination of straight line, circles, ellipse etc., and if we are
able to generate these basic figures, we can also generate combinations of
them. Once we have drawn these pictures, the need arises to
transform these pictures.
We are not essentially modifying the
pictures, but a picture in the center of the screen needs to be shifted to
the top left hand corner, or a picture needs to be increased to twice its size
or a picture is to be turned through 900. In all these
cases, it is possible to view the new
picture as really a new one and use
algorithms to draw them, but a better method is, given
their present form, try to get their new counter parts
by operating on the existing data. This concept is called transformation.
The three basic transformations are:
- Translation
- Rotation and
- Scaling.
1. Translation:
Translation is the
process of changing the position of an object.
Translation refers to the shifting of a
point to some other place, whose distance with
regard to the present point is known. Let an object point P(x,y)=xI+yJ be moved to
P’(x’,y’) by the given translation vector V= txI + tyJ, where tx and ty is the
translation factor in x and y directions, such that
P’=P+V.
Example of Translation:
2. Rotation:
Rotation
as the name suggests is to
rotate a point about an axis. The axis can be any of the
coordinates or simply any other specified line also. A
two-dimensional rotation is applied to an object by repositioning it along a
circular path in the x-y plane. When we generate a rotation we get a rotation
angle (θ) and the position about which the object is rotated (xr , yr) this is
known as rotation point or pivot point. The transformation can also be
described as a rotation about rotation axis that is perpendicular to x-y plane
and passes through the pivot point. Positive values for the rotation angle
define counter-clockwise rotations about the pivot point and the negative
values rotate objects in the clockwise direction.
Example of Rotation:
3. Scaling:
Scaling is the concept of
increasing or decreasing the size of a picture. When it is
done in both directions, the increase or decrease in both
directions need not be same. To change the size of the picture,
we increase or decrease the distance between the end points of the picture
and also change the intermediate points are per requirements.
Example of Scaling:
Reference : www.ecomputernotes.com
