Name:         GRLIN3

Purpose:      draw a thick line (multiple strokes)

Category:     GRAPHICS

File:         pgplot.src

Author:       T.J. Pearson

Use:          see description below.

Description:

            SUBROUTINE GRLIN3 (X0,Y0,X1,Y1)
      
       GRPCKG: draw a heavy line from (X0,Y0) to (X1,Y1) by making multiple
       strokes.  In order to simulate a thick pen, the line drawn has
       circular, rather than square, end points.  If this is not done,
       thick letters and other figures have an abnormal and unpleasant
       appearance.
      
       Vocabulary:
      
       LINEWT: the number of strokes required to draw the line; if
             this is odd, one stroke will lie along the requested vector.
             The nominal line thickness is (LINEWT-1)*0.005 in.
       RSQURD: the square of the semi-line thickness.
       (DX,DY): the vector length of the line.
       (VX,VY): a vector of length 1 pixel in the direction of the line.
       (VY,-VX): a vector of length 1 pixel perpendicular to (VX,VY).
       OFF: the offset parallel to (VY,-VX) of the K'th stroke.
       (VXK,VYK): the vector increment of the K'th stroke to allow for the
             semi-circular terminal on the line.
       (PXK,PYK): the vector offset of the K'th stroke perpendicular to the
             line vector.

Updates:      Oct 16, 1998: JPT automatically extracted from source.