Next: 7.5 Conversions Up: 7 Internal programs Prev: 7.3 Particular displays Contents

7.4 Basic manipulations

•      SUBROUTINE GENPLY(R, A, N, T)
       INTEGER N
       REAL R, A, T(2, N+1)
  

  generates N+1 (X, Y) couples in T, defining a   polygon with N sides centered at the origin, with radius R and angle A.

•       SUBROUTINE ARC3P(P1, P2, P3, RES)
        REAL P1(2), P2(2), P3(2), RES(5)
  

  calculates the arc  of a circle going through the 3 points, P1, P2 and P3, by joining them in this order, where on exit RES(1:5) defines the arc in the following manner:

  RES(1), RES(2): first point on the arc;

  RES(3), RES(4): arc's center;

  RES(5): angle of arc.

•       REAL FUNCTION DIST2P(P1, P2)
        REAL P1(3), P2(3)
  

  returns the  distance of 2 points: DIST2P=distance(P1, P2)

•       SUBROUTINE DP1DR(D, P1, DR)
        REAL D(3), P1(2), DR(2)
  

  returns D, the  line going through a point (P1) and perpendicular to a direction (DR). The line's equation is given by: D(1)*x + D(2)*y + D(3) =0

•       SUBROUTINE DPP(D, P1, P2, IRES)
        SUBROUTINE DP1P2(D,P1,P2,IRES)
        REAL D(3), P1(2), P2(2)
        INTEGER IRES
  

  returns D, the line going through  two points P1 and  P2. IRES=0 if OK.

  The line's equation is given by: D(1)*x + D(2)*y + D(3) =0

•       REAL FUNCTION DTP1D1(P, D)
        REAL P(2), D(3), X
  

  returns DTP1D1, the   distance of point P from line D. The line's equation is given by: D(1)*x + D(2)*y + D(3) =0

•       REAL  FUNCTION DTP1P2(P1, P2)
        REAL P1(2), P2(2), DX, DY
  

  returns DTP1P2, the distance between point P1 and  point P2.

•       REAL FUNCTION DTP1SG(P, P1, P2)
        REAL P1(2), P2(2), P(2)
  

  returns DTP1SG, the distance   of point P from the segment defined by the 2 points, P1 and P2.

•       SUBROUTINE ITDD(P, D1, D2, IRES)
        SUBROUTINE ITD1D2(P, D1, D2, IRES)
        REAL P(2), D1(3), D2(3)
  

  returns P, the  intersection point of   two lines D1 and D2 defined by D1(1:3) and D2(1:3). IRES = 0 if OK.

•       SUBROUTINE MDP1P2(D, P1, P2, IRES)
        REAL D(3), P1(2), P2(2)
  

  returns D, the bisecting line  of the segment going through points P1 and P2. The line's equation is given by: D(1)*x + D(2)*y + D(3) =0

•       SUBROUTINE PJPD(P, P1, D1)
        SUBROUTINE PJP1D1(P, P1, D1)
        REAL P(2), D1(3), P1(2)
  

  returns P, the projection point  of P1 on   line D1. The line's equation is given by: D1(1)*x + D1(2)*y + D1(3) =0

•       SUBROUTINE SLOPE(PE, PT, C, R, IRES)
        REAL PT(2), C(2), R, PE(3)
  

  returns PE, the   slope of the line going through PT, tangent to circle (C, R).