#include "slalib.h" #include "slamac.h" void slaXy2xy ( double xc1, double yc1, double coeffs[6], double *xc2, double *yc2 ) /* ** - - - - - - - - - ** s l a X y 2 x y ** - - - - - - - - - ** ** Transform one [x,y] into another using a linear model of the type ** produced by the slaFitxy routine. ** ** Given: ** xc1 double x-coordinate ** yc1 double y-coordinate ** coeffs double[6] transformation coefficients (see note) ** ** Returned: ** *xc2 double x-coordinate ** *yc2 double y-coordinate ** ** 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 present routine performs the transformation: ** ** xc2 = a + b*xc1 + c*yc1 ** yc2 = d + e*xc1 + f*yc1 ** ** See also slaFitxy, slaPxy, slaInvf, slaDcmpf. ** ** Last revision: 5 December 1994 ** ** Copyright P.T.Wallace. All rights reserved. */ { *xc2 = coeffs[0] + coeffs[1] * xc1 + coeffs[2] * yc1; *yc2 = coeffs[3] + coeffs[4] * xc1 + coeffs[5] * yc1; }