Types of Geometric Transformations Scaling and Mirror Reflections

Types of Geometric Transformations: Scaling and Mirror Reflections Subject: Computer Graphics By: Dr. Piyush Kumar Singh 1

Scaling with respect to Origin: • 2

Scaling with respect to Origin: • 3

Scaling with respect to Origin: If we have the value of scaling factors along the x axis as 2 and along the y axis as ½ then we have: (Example) 4

Scaling with respect to Origin : Example In above figure it is simply shown that in figure (a) the four corners of the square (1, 1), (1, 2), (2, 1) and (2, 2). Since the scaling along the x axis is given as 2 and scaling along the y axis is given as ½. This means that the value of Sx= 2 and Sy= ½. Then we use following formula: 5

Scaling with respect to Origin : Example •

Mirror Reflection about an axis: ØEither X or Y axis can be treated as mirror. ØWe have mirror reflection either taking X axis as mirror or Y axis as mirror. ØRemember in case of image in mirror the image inside mirror is seems to be located at same distance as the distance of object from mirror.

Mirror Reflection about X-axis: •

Mirror Reflection about Y-axis: •

Mirror Reflection about axis: Figure

References: • Donald Hearn and M. Pauline Baker, “Computer Graphics C Version‟, Prentice – Hall of India • Zhigang Xiang and Roy A Plastok, “Computer Graphics” Tata Mc. Graw Hill Education Private Limited, Second Edition

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