Grabovac, Marijana

Putnik, Zoran

Putnik Zoran

Grabovac Marijana

University of Szeged

Extension of Java with Turtle GraphicsZoran Putnik and Marijana GrabovacComputer graphics has entered all aspects of computer usage, especially after introduction ofWorld Wide Web into everyday life and after the number of people who are using it increased. Thisemphasized the need for better quality and enlarged quantity of graphics we are faced with. At thesame time, WWW induced new and powerful concept - programming language Java. This program-ming language, together with technical and technological improvements, brought the possibility ofinclusion of larger amount of multimedia elements and network into all kinds of software.On the other hand since the invention of programming language LOGO, turtle graphics has beenrecognized as an excellent educational tool. It is especially suitable for a development of proceduralthinking, offering more natural way for unification of a program with data structures and servingas a ready-made prototyping tool. The language was designed at Bolt Beranek and Newman INC,in Cambridge, Massachusetts, USA, in the late 1960s [1]. The real reason for its development wastesting of an idea that programming may be used as an educational discipline to teach children,especially about notions hard for understanding (mathematical concepts, experiments with abstractconcepts).In any programming language, there are two basic ways of employing computer graphics: usageof basic graphic functions and usage of turtle graphics. While the use of basic graphics functionsconfirms essentially to use of (any) other (kind of) functions of a given language, turtle graphics, lessknown and used, has its own "rules" and techniques, common for every language. Traditionally andinformally, turtle graphics may be described as a process of picture creation through a movement of"an animal" (i.e. a turtle), which crawls across a screen, towing a pencil and leaving a trail [1].Turtle graphics has been explored at the Institute of Mathematics in Novi Sad for some time, and itwas at first introduced as an extension of functional programming language LispKit LISP developedat the Institute [2]. Later, research concentrated on educational values of turtle graphics in [3]. Asit may be noticed, at the time, study focussed on combination of functional programming and turtlegraphics. Yet, with the introduction and expansion of Java programming language, some problemsexistant in mentioned research, related with functional programming are naturally overcame.Now, turtle graphics has been implemented in Java programming language as one Java applet.The implementation of turtle graphics in Java is important because it brings the expressiveness ofLOGO to Java language. At the same time, implementation of turtle graphics in Java programminglanguage implicitly introduced it into several other operating systems. Java applets, with easy controlof mouse, buttons, "choices" and authority over the computer even for non-programmers enabledgreater concentration on abilities of turtle graphics and their use in education.The choice of Java programming language proved as an excellent one, since we got a languagethat is portable, interpreted, high-performance, simple and object-oriented, which are all characteris-tics of a modern programming language of a high quality.In this paper we have implemented something that has already proved its educational and creativevalue. In this way we have presented it to the wider public in the environment that is secure and userfriendly. Since the program was carried out in Java it can operate on any platform (operating system)without the need for recompilation or reimplementation.References[1] Ross, P. LOGO Programming for the IBM OC, Addison Wesley, Wokingham.[2] Putnik, Z., Budimac, Z., and Ivanovic, M. Turtle Walk Through Functional Language, SIG-PLAN Notices, Vol. 26, no. 2, pp 75-82.[3] Putnik, Z., and Budimac, Z., Bringing LOGO to the World of Purely Functional Programming,In Proc. of ’EUROLOGO ’97’ - Conference, Budapest, Hungary, pp. 406-409.87

Extension of Java with Turtle graphics : [abstract]

http://acta.bibl.u-szeged.hu/59623/1/cscs_2000_087.pdf

Extension of Java with Turtle graphics

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