Visualizations for the Web

Abstract: This thesis report describes the implementation of a chart library for use in client-sidebrowser visualizations. The library is completely written in the JavaScriptprogramming language and supports five chart types: bar or column charts, line charts,histograms, scatter plots, and function plots. Function plotting is performed usinginterval arithmetic resulting in accurate and guaranteed correct function plots withone or two variables. Other charts are drawn according to the guidelines set out inStephen Few's "Show Me the Numbers: Designing Tables and Graphs to Enlighten"book in order to create clear and consistent visualizations of data. The design of the library is based on the concept of components and containerswhich are laid out using layout managers. Three layout managers are included bydefault: border, grid, and a flexible grid. The charts are drawn using the HTML5Canvas element and maintain their own transformation stack in order to create crisplines and shapes. The design of the library also contains several extension mechanismwhich enables the creation of custom components and chart plug-ins as well ascustomization of the colours and fonts used in the charts. The library also extends the JavaScript language by adding support for severalfunctional programming constructs. Examples of these constructs are: functionalpattern matching, iterators such as map and reduce, mixins, getter and setterproperties, function currying, and others.