A Simple and Fast Line-Clipping Method as a Scratch Extension for Computer Graphics Education

摘要

Line clipping is a fundamental topic in an introductory computer graphics course. An understanding of a line-clipping algorithm is reinforced by having students write actual code and see the results by choosing a user-friendly integrated development environment such as Scratch, a visual programming language especially useful for children. In this article a new computation method for 2D line clipping against a rectangular window is introduced as a Scratch extension in order to assist computer graphics education. The proposed method has been compared with Cohen-Sutherland, Liang-Barsky, Cyrus-Beck, Nicholl-Lee-Nicholl and Kodituwakku-Wijeweera-Chamikara methods, with respect to the number of operations performed and the computation time. The performance of the proposed method has been found to be better than all of the above-mentioned methods and it is found to be very fast, simple and can be implemented easily in any programming language or integrated development environment. The simplicity and elegance of the proposed method makes it suitable for implementation by the student or pupil in a lab exercise.