2 elliptic common tangent creation manners and graphics processing device

摘要

PURPOSE: To provide a common tangent preparing method which prepares a common tangent between two ellipses stably without any contradiction and the graphic processor. ;CONSTITUTION: This common tangent preparing method, which prepares the common tangent between the two ellipses by using a computer, has steps S1 and S2 for the coordinate conversion two ellipses to a coordinate system where the center point of one ellipse meets the origin and a major-axis vector matches the X axis, steps S3 and S4 for finding the number of intersections of the two ellipses after the conversion and finding the phase relation between the two ellipses from the found number of intersections and the positions of the two ellipses, a step S5 for deciding the number of common tangent by a found phase relation, a step S6 for finding solutions in parametrics representation as many as common tangents from the two coordinate-converted ellipses on the basis of an evaluation function in specific parametrics representation, and a step S7 for converting the found solution in parametrics representation into coordinate values in the actual space.;COPYRIGHT: (C)1996,JPO