Algorithmization in a Computer Graphics Environment Zuzana Homanova1,2 and Tatiana Havlaskova1,2 1University of Ostrava, Frani Sramka 3, Ostrava, Czech republic 2Department of Information and Communication Technologies in Education, Czech republic Keywords: Algorithmization, Vector Graphics, Learning, Vector Software, ICT in Education. Abstract: Today’s digital age makes it possible for people to communicate via video or images. Therefore, computer graphics is part of the elementary school curriculum. The paper is aimed at updating computer science education at Czech elementary schools; it shows how pupils could develop their computational thinking when creating vector graphics based on basic geometric shapes such as a circle, ellipse, square, rectangle and others. The following methods were chosen to present the proposed processes: verbal expression for an algorithm, visual projection and a flowchart. 1 INTRODUCTION algorithmization and algorithmic thinking in all these situations. Schools and school facilities are currently trying to respond to dynamic changes related to the 1.2 Algorithm, Algorithmic Thinking development of digital technologies. Pupils need to develop their computational thinking as it is How can algorithmization be defined? The term itself th considered one of the key competencies. dates back to the turn of the 8 century A.D. when The paper shows why it is important that pupils Arabia mathematician Abū ʻAbd Allāh Muhammad develop algorithmic thinking processes, defines ibn Mūsā al-Chwārizmī published two books on algorithmic thinking and stresses its importance in solving linear and quadratic equations. Today, the last education. part of his name – al-Chwārizmī – is known as The Strategy for Education Policy of the Czech Algorismi, i.e. algorithm (Online Etymology Republic Until 2020 (MŠMT, 2017) states that pupils Dictionary, 2018). should be able to not only use modern technology, but Educational institutions should help pupils develop also understand it and even create it. One of the algorithmic thinking as it is one of the key projects that supports this notion is PRIM (Supporting competencies though which they can learn how to use the Development of Computational Thinking, information and communication technology and imysleni.cz). incorporate it into their everyday lives. The following The paper is aimed at the basic method of creating are the basic components of algorithmic thinking: vector graphics through objects and its algorithmic . Functional decomposition (into smaller parts); expression via words, visual projection and a . Use of data; flowchart. Term generalization; . Proceeding step by step; 1.1 General Issues of Algorithmization . … Many authors are of the opinion that algorithmic There are many everyday activities where one needs to thinking is a cognitive process concept with a clearly follow instructions or the sequence of steps to achieve defined sequence of mental operations (with every the correct result – the output state. Consider, for important one being described in detail or optimized) instance, cooking following the recipe, assembling and end result (Pervin, 2007). furniture following the instructions, or activities a However, there is another definition, which person performs from the moment they wake up until describes algorithmic thinking as a set of mental they have to leave for work. There are elements of operations, actions, methods and strategies aimed at 466 Homanova, Z. and Havlaskova, T. Algorithmization in a Computer Graphics Environment. DOI: 10.5220/0007752704660473 In Proceedings of the 11th International Conference on Computer Supported Education (CSEDU 2019), pages 466-473 ISBN: 978-989-758-367-4 Copyright c 2019 by SCITEPRESS – Science and Technology Publications, Lda. All rights reserved Algorithmization in a Computer Graphics Environment completing a theoretical and practical task, with algorithm will be) (Krček, Kreml, 1993; Pšenčíková, algorithms being the result (Kopayev, 2018). 2009). There are many ways to write an algorithm – Different literatures define the terms algorithm and verbal description, graphic representation using a algorithmic thinking in different ways. However, for flowchart and instruction sequence using images. the purposes of this paper, the following definition is accurate enough. It describes an algorithm as a specific 2.1 Verbal Description of an Algorithm way of solving a problem with clearly defined guidelines. Verbal description of an algorithm helps us express In the last two decades, many scholars have tried any activity realized in everyday situations. to define the term algorithmic thinking, arguing that it Crossing a street with traffic lights: is the most important competence which pupils can 1. Go right up to the traffic lights. learn in school (Snyder, 2000). 2. Is a red light on? In the broader context, algorithmic thinking is a set Yes – wait, go back to Point 2. of skills aimed at constructing and understanding an algorithm: No – continue to Point 3. Ability to analyze problems; 3. Cross the street. Ability to specify a problem; Even though it is evident that a number of (not . Ability to find operations required to solve a only) everyday activities could be expressed through a problem; verbal description of an algorithm, it could also lead to . Ability to use basic operations to construct a inaccuracies caused by different formulations and/or correct algorithm for a particular problem; figures of speech. A natural language should be . Ability to consider all problem variations (both replaced with a structured language, i.e. a natural normal and specific); language bound by certain rules. Ability to make an algorithm more effective. 2.2 Algorithm Flowchart (Futschek, 2006). Graphic representation of an algorithm through a Without algorithmic thinking, one cannot possibly flowchart is often used. It uses pre-defined structures construct algorithms and processes for solving difficult and symbols which make the algorithm easier to problems. Futschek (2018, p. 160) agrees with this understand. statement, arguing that algorithmic thinking is a highly creative process. If one is to construct an algorithm, The following are the main flowchart symbols: they need to have mastered algorithmic thinking. 2 ALGORITHM PROPERTIES Figure 1: Symbol for the beginning and the end. An algorithm must have the following properties: . Determination – each step needs to be clearly defined. There cannot be a situation where it is not clear which steps will follow. Generality – the created algorithm is applicable to Figure 2: Symbol for an operation, instruction. all problems of a similar nature, not only one type. Resultativity – realization of a particular number of steps leads to the correct result. Finality – following the realization of individual steps, each algorithm must end. Figure 3: Symbol for a Condition, Decision. There are situations when one can reach the correct result through various algorithms with different A flowchart representing a verbal description of numbers of steps, with the aforementioned number of crossing a street with traffic lights may have the steps (i.e. the effectiveness of an algorithm) playing the following form: key role. The less steps an algorithm has, the shorter the realization time will be (and the more effective the 467 CSEDU 2019 - 11th International Conference on Computer Supported Education S 2.3 Picture Instructions The sequence of instructions can also be expressed through various pictures, symbols or even Come to the traffic light pictograms, helping to bring algorithmization to the attention of a wider public (today, it is used almost exclusively by experts, teachers and pupils of computer science and other related fields). Is the red light on Go through the No the traffic light? transition Yes Figure 6: Picture instructions (source: Keliwood.cz). Wait F Figure 4: Crossing a street with traffic lights. 3 COMPUTER GRAPHICS The following figure presents an interesting view Computer graphics is dynamically developing. of how a flowchart could be used in the music Thanks to the widespread use of mobile technology industry (Lessner, 2014): and graphic applications and software, graphics has become ubiquitous in the lives of people of different age groups. Not only cameras built into mobile devices, but also mobile applications, web applications, commercial and open source software, creative filters, GIF images, graphic file databases, shared galleries and other online tools help us develop our creativity. Computer graphics can be divided into: . Raster graphics, . Vector graphics. Both vector and raster graphics have their unique features such as the properties of graphic files and the way they are used. One of the main differences is the way in which a particular object is described (Procházková et al., 2007). While raster graphics uses pixels, vector graphics is based on Bézier curves and mathematical shapes (circles, ellipses, polygons, etc.) defined by mathematical equations. Both raster and vector graphics can also be used at another graphic level. Vector graphics is used for creating illustrations, diagrams, promotional materials Figure 5: The song “Hey Jude”. (leaflets, business cards, and logotypes), etc. Vector graphics is taught in elementary school (as part of the Why is it better to use a graphic representation than a subject "Informatics"). verbal description of an algorithm? However, this division is not the only one. There . We can see the entire structure of an algorithm, not