PARALLEL LINE GENERATION METHOD IN DRAWING INPUT DEVICE

PURPOSE: To automatically set a parallel line generation direction, to reduce the trouble of operation and to shorten the work time by indicating the feature points of intersection points of center lines and the bending points of a quadrangle at the starting point and the end point of a reference line. CONSTITUTION: The starting point of a reference line is given by a mouse and a keyboard. When the starting point is given, whether the feature points such as the bending points (apexes) A, B, C and D of a pole, the intersection points E, F, G and H between the center lines and a pole lines, and a point I (approximate point) on a wall line, which is the nearest from the starting point exist in a prescribed radius from the starting point or in the range of a square with a side where the starting point is set to be a centroid is searched and judged. When the plural feature points exist in the search range by the judgement, the feature point nearest to the starting point is selected. The parallel line generation direction is set in accordance with the feature point, the passing point of the reference line is given and then the end point of the reference line is given. Then, the parallel line generation direction of the end point of the reference line is set in the same way as the starting point of the reference line.