PTSIGN

s = PTSIGN (Ax, Ay, Bx, By, Qx, Qy)

The sign of point Q from line segment A->B. Point Q is given by the coordinates (Qx, Qy), A by (Ax, Ay) and B by (Bx, By).

Example 1:

' Define line
Bx = 100
By = 100
Cx = 200
Cy = 150

' Define point
Ax = 150
Ay = 50

Sign = PTSIGN(Bx, By, Cx, Cy, Ax,Ay) 
print "Sign of point relative to the line "; Sign

Example 2: Interactive example to illustrate the geometry of PTDISTLN

' Interactive example to illustrate the geometry of PTDISTLN

Bx = 200
By = 300
Ax = 300
Ay = 100

pen on
while(!pen(12))

  cls
  print "Move Mouse. Press Left Mouse Button to exit"
  
  Cx = pen(10)
  Cy = pen(11)
  
  Sign = PTSIGN (Bx,By,Cx,Cy,Ax,Ay) 
  print "Sign of point relative to the line "; Sign
  
  ' Draw
  line Bx, By, Cx, Cy color 10   ' Line
  circle Ax, Ay, 5 color 11      ' Cirlce at position of the point
  showpage
  delay(50)
  
wend

ABS ABSMAX ABSMIN ACOS ACOSH ACOT ACOTH ACSC ACSCH ASEC ASECH ASIN ASINH ATAN ATAN2 ATANH ATN CEIL COS COSH COT COTH CSC CSCH DEG DERIV DETERM DIFFEQN EXP EXPRSEQ FIX FLOOR FRAC INT INTERSECT INVERSE LINEQN LOG LOG10 M3APPLY M3IDENT M3ROTATE M3SCALE M3TRANS MAX MIN POLYAREA POLYCENT POLYEXT POW PTDISTLN PTDISTSEG PTSIGN RAD RND ROOT ROUND SEC SECH SEGCOS SEGLEN SEGSIN SEQ SGN SIN SINH SQR STATMEAN STATMEANDEV STATMEDIAN STATSPREADP STATSPREADS STATSTD SUM SUMSQ TAN TANH TRANSPOSE