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.