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Pawan Kumar, Lovely Professional University Unit 9: Clipping I

Unit 9: Clipping I

CONTENTS
Objectives
Introduction

9.1 Overview of Clipping
9.2 Point Clipping
9.3 Line Clipping
9.3.1 Cohen Sutherland Algorithm
9.3.2 Midpoint Subdivision Algorithm
9.3.3 Liang-Barsky Algorithm

9.4 Summary
9.5 Keywords
9.6 Self Assessment
9.7 Review Questions
9.8 Further Readings

Objectives

After studying this unit, you will be able to:
• Explain point clipping
• Explain line clipping
• Explain midpoint subdivision
Introduction

A scene consists of collection of objects that are specified in world coordinates(x and y axis). When a
scene is displayed, you can view only that objects which are inside the viewing window (clip window)
and clip everything outside the v window. The clipping algorithms are developed to identify which
points and lines should be clipped and which ones should be retained.
The clipping algorithm is the procedure that helps to identify those portions of a picture that are either
inside or outside the specified window frame at the time of clipping. The picture region against which
the object is supposed to be clipped is called as a clip window.
Clipping algorithms are important in computer graphics. They are used to view transformations and
erase picture sections in drawing and painting packages. They are also used in many window manager
systems such as GNOME.

GNOME is a graphical user interface that includes a variety of features such as file
archiving tool, file search tool and games.

The window manager systems provide a function to create and manipulate the display of multiple
processes.

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