Name: GRCLPL Purpose: clip line against clipping rectangle Category: GRAPHICS File: pgplot.src Author: T.J. Pearson Use: see description below. Description: SUBROUTINE GRCLPL (X0,Y0,X1,Y1,VIS) GRPCKG (internal routine): Change the end-points of the line (X0,Y0) (X1,Y1) to clip the line at the window boundary. The algorithm is that of Cohen and Sutherland (ref: Newman & Sproull). Arguments: X0, Y0 (input/output, real): device coordinates of starting point of line. X1, Y1 (input/output, real): device coordinates of end point of line. VIS (output, logical): .TRUE. if line lies wholly or partially within the clipping rectangle; .FALSE. if it lies entirely outside the rectangle. Updates: Oct 16, 1998: JPT automatically extracted from source. Oct 24, 1998: JPT use GIPSY's IANDF function instead of IAND