Computer Graphics, Chapter 4: 2D Geometrical Transformations

Computer Graphics, Chapter 4: 2D Geometrical Transformations

In many applications of computer graphics, we need to alter and manipulate displayed graphical objects either interactively or non-interactively. One such an application is animation. Even when selecting an icon on your desktop and moving it from one location of screen to other, its transformation. Similarly, when you move any object, GUI Frame, icon, image, in you Windows or Linux OS, that operation is technically known as Transformation.  Such kinds of alteration and manipulation of displayed graphical objects are classified under the generic name geometrical transformation. Generally, it can be said that the geometrical transformations are the ways or tools or techniques by which we can easily modify or change the shape, size, position and orientation of displayed objects on active output devices.
There are generally four basic types of transformations namely, translation, rotation, scaling, and Shear. Whereas, reflection being part of transformation is usually considered as oppsite or negative scale. 

• Translation means change in position, location or displacement of object on screen.
• Rotation means change in direction, orientation, or angle of object.
• Scale means change in size of object.
• Shear is an operation referring to change in proportion of an object, when the shape of object is modified or altered to a different unique form. 

 Lecture Contents

 • Translation

 • Scaling

 • Rotation

 • Shear

 • Matrix notation

 • Compositions

 • Homogeneous coordinates

Computer Graphics, Chapter 4: 2D Geometrical Transformations