A High-Level Language for Specifying Pictures

Abstract

A programming language that includes special constructs for drawing pictures is discussed. The language has been designed so that programs to draw pictures can reflect the structure of those pictures. Picture elements are called boxes. They are defmed by declaring algebraic relationships that should exist among their significant points and requesting actions to be performed at those points. The algebraic relationships are processed by an equation solver to determine the absolute location of significant points. A new mechanism of variable reference and scope makes the expression of relationships that should exist among picture elements more direct than it is in conventional languages. Some common picture operations--drawing lines using a pattern, filling in areas with textures, and obscuring parts of a picture by other parts--are all expressed readily once the mechanism for defining and using boxes is in place. The language has been implemented, and used by several authors to prepare figures for their papers and books. It was also used to prepare this paper. © 1982, ACM. All rights reserved.