The model relates two sets of [x,y] coordinates as follows. Naming the elements of coeffs:

  coeffs[0] = A
  coeffs[1] = B
  coeffs[2] = C
  coeffs[3] = D
  coeffs[4] = E
  coeffs[5] = F

the model transforms coordinates [x1,y1] into coordinates [x2,y2] as follows:

  x2 = A $+$ B $\ast$ x1 $+$ C $\ast$ y1
  y2 = D $+$ E $\ast$ x1 $+$ F $\ast$ y1

The transformation can be decomposed into four steps:

1) Zero points:
  x’ = xz $+$ x1
  y’ = yz $+$ y1

2) Scales:
  x’’ = xs $\ast$ x’
  y’’ = ys $\ast$ y’

3) Nonperpendicularity:
  x’’’ = cos(perp / 2) $\ast$ x’’$+$ sin(perp / 2) $\ast$ y’ ’
  y’’’ = sin(perp / 2) $\ast$ x’’$+$ cos(perp / 2) $\ast$ y’ ’

4) Orientation:
  x2 = cos(orient) $\ast$ x’’’$+$ sin(orient) $\ast$ y’’’
  y2 = -sin(orient) $\ast$ y’’’$+$ cos(orient) $\ast$ y’’’

palDcmpf ( double coeffs[6], double $\ast$xz, double $\ast$yz, double $\ast$xs, double $\ast$ys, double $\ast$perp, double $\ast$orient )

coeffs = double[6] (Given)

xz = double (Returned)

yz = double (Returned)

xs = double (Returned)

ys = double (Returned)

perp = double (Returned)

orient = double (Returned)

palFitxy, palPxy, palInvf and palXy2xy