On orders in visual interaction

Visual languages can be defined as sets of visual sentences, composed of images, descriptions, and of the relationships between them. In this paper, we identify the emergence of various kinds of orders when managing visual sentences. We first define orders separately on images and descriptions and next we combine them to define orders on visual sentences. A number of different visual transformations are also presented which preserve the defined orders; examples are given to illustrate the intuition and motivation behind such orders. We claim that the analysis of these orders provides insight for the design of visual interaction languages allowing the users to control and steer interactive computations. (C) 1999 Academic Press.