1 #include <u.h> 2 #include <libc.h> 3 #include "map.h" 4 /* refractive fisheye, not logarithmic */ 5 6 static double n; 7 8 static int Xfisheye(struct place * place,double * x,double * y)9Xfisheye(struct place *place, double *x, double *y) 10 { 11 double r; 12 double u = sin(PI/4-place->nlat.l/2)/n; 13 if(fabs(u) > .97) 14 return -1; 15 r = tan(asin(u)); 16 *x = -r*place->wlon.s; 17 *y = -r*place->wlon.c; 18 return 1; 19 } 20 21 proj fisheye(double par)22fisheye(double par) 23 { 24 n = par; 25 return n<.1? 0: Xfisheye; 26 } 27