C'era un'altra cosa che non funzionava a dovere, la freccia era sempre senza retino. Inoltre era spostata un po' a destra rispetto al centro del tubo.
300: !!!===== Arrow - Slope direction points 7-14 ========
!!POLY2 n, frame_fill, x1, y1, ... xn, yn
!!An open or closed polygon with n nodes. Restriction of parameters: n >= 2
!!frame_fill = j1 + 2*j2 + 4*j3.....where j1, j2, j3 can be 0 or 1.
!!j1 (1): contour only
!!j2 (2): fill only
!!j3 (4): close an open polygon
!!poly2_b 5, 2, s, fill_pen_arrow,back_pen_arrow,
IF lev_right>lev_left THEN mi=1 ELSE mi=-1
x[7] = xx + (COS(ang) * diameter*1.25 - diameter/4)*mi !!point 7
y[7] = yy + (SIN(ang) * diameter*1.25) + diameter/4
x[8] = x[7] - (SIN(ang) * diameter/10)*mi !!point 8
y[8] = y[7] + (COS(ang) * diameter/10)
x[9] = x[8] + (COS(ang) * diameter/2)*mi !!point 9
y[9] = y[8] + (SIN(ang) * diameter/2)
x[10] = x[9] - (SIN(ang) * diameter/10)*mi !!point 10
y[10] = y[9] + (COS(ang) * diameter/10)
x[11] = x[7] + (COS(ang) * diameter)*mi !!point 11
y[11] = y[7] + (SIN(ang) * diameter)
x[14] = x[7] + (SIN(ang) * diameter/10) *mi !!point 14
y[14] = y[7] - (COS(ang) * diameter/10)
x[13] = x[14] + (COS(ang) * diameter/2) *mi !!point 13
y[13] = y[14] + (SIN(ang) * diameter/2)
x[12] = x[13] + (SIN(ang) * diameter/10)*mi !!point 12
y[12] = y[13] - (COS(ang) * diameter/10)
ADD2 (-diameter*1.5)*mi,0
pen robPen
line_type robLine
line2 x[7], y[7], x[8], y[8]
line2 x[8], y[8], x[9], y[9]
line2 x[9], y[9], x[10], y[10]
line2 x[10], y[10], x[11], y[11]
line2 x[7], y[7], x[14], y[14]
line2 x[14], y[14], x[13], y[13]
line2 x[13], y[13], x[12], y[12]
line2 x[12], y[12], x[11], y[11]
FILL fill_type
POLY2_B 9, 2, fill_pen_arrow, back_pen_arrow,
x[7], y[7], 0,
x[8], y[8], 0,
x[9], y[9], 0,
x[10], y[10], 0,
x[11], y[11], 0,
x[12], y[12], 0,
x[13], y[13], 0,
x[14], y[14], 0,
x[7], y[7], -1
DEL 1
return
ho aggiunto anche un comando per invertire la freccia, se il livello di destra è più alto di quello a sinistra.