Data Structures in Computer Graphics

Abstract

This chapter focuses on data structures in computer graphics. A central problem in interactive graphical applications is that of structuring the data. Frequently the graphical data and the non-graphical data are maintained in separate data-bases with different structures. If one attempts to use the graphical medium as a window to the data in the data base and attempts to make changes in the data-base by interactively altering displayed images, then conversions are required between the graphical structures and the primary data files. The picture-building system consists of three parts: (1) a mechanism for creating structures for graphical and non-graphical data, (2) a mechanism for interactively loading data into these structures, and (3) a mechanism for viewing and interactively manipulating the graphical data via pictures. The concept of a data definition language for defining relational structures is extended for graphical data by assigning “meanings” to domain names. Correlation is the identification of a line, entity, or group of entities in the data-base structure by pointing at its representation on the screen.