Calculate parallel to a line

C call:

C     CALL PTH011 (X1,Y1,X2,Y2,RL,ABST,X3,Y3,X4,Y4,LUWRIT,LUREAD)

C     

C     The following variables must be defined beforehand:

C     

C     X1/Y1  : X/Y coordinate of point 1

C     X2/Y2  : X/Y coordinate of point 2

C     RL     : Side, seen from the first point to the second point

C              -1.0 = left

C               1.0 = right

C     ABST   : Distance

C     X3/Y3  : X/Y coordinate of point 1 of the parallels (return value)

C     X4/Y4  : X/Y coordinate of point 2 of the parallels (return value)

C     LUWRIT : is not evaluated, but must be specified

C     LUREAD : is not evaluated, but must be specified

C     

C     Example:

C     ----------------------------------

C     Calculate parallel to a line

C     ----------------------------------

      X1 = 50.0

      Y1 = 50.0

      X2 = 80.0

      Y2 = 100.0

      RL = -1.0

      ABST = 15.0

      CALL PTH011 (X1,Y1,X2,Y2,RL,ABST,X3,Y3,X4,Y4,LUWRIT,LUREAD)