Graphics display system and method including preclipping circuit

Claim 1

A graphics display system comprising vector memory means for storing vector data representing one or more graphics images to be displayed, wherein said vector data represents one or more polygons where each polygon representation includes header information specifying the format of said representation and where each polygon includes line segments having at least one vertex, memory update means including means for inserting said vector data into said vector memory means, means for modifying said vector data within said vector memory means, and preclipper means for retrieving said vector data from said vector memory means, clipper means for clipping specified ones of said polygons and for identifying specified ones of said polygons by a closest point, by a closest segment, and by partial or complete containment within a window, scaler means for translating and scaling ones of said polygons thereby transforming the image to be displayed, raster memory means, writing means for rasterizing the transformed vector data into said second memory means thereby forming raster data, reading means for reading said rasterized data from said raster memory means thereby forming raster data, reading means for reading said reasterized data from said raster memory means, monitor means for displaying said graphics image and processor means for controlling the operation of said system, and wherein said preclipper means include means for circumscribing a rectangle around one of said polygons and means for determining whether the circumscribed rectangle intersects a specified window.