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    Liberation from Rectangles: A Tiling Method for Dynamic Modification of Objects on Raster Displays
    (Eurographics Association, 1988) Slater, Mel; Davison, Allan; Smith, Mark
    When graphics objects (also called segments) are used on raster display hardware, problems arise because of the mismatch between the high level requirements of object manipulation, and the low level representation from which the image is refreshed. This paper describes a tiling algorithm which provides a solution to the problems of damage repair and hit detection. In particular methods for handling object priority are discussed and experimental results showing the performance of the algorithm for a number of cases are presented.
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    A Top Down Method for Interactive Drawing
    (Blackwell Publishing Ltd and the Eurographics Association, 1988) Slater, Mel
    Traditional interactive drawing programs adopt a bottom-up approach, allowing the user to construct a picture by the use of discrete tools, for example, lines, circles, rectangles, and so on. This paper presents a different approach, which allows users to construct graphical objects by stretching and cutting existing objects. The representation is simply implemented, based on a ring of cubic Bezier curves, and use of the de Casteljau algorithm.