PostGIS  2.3.8dev-r@@SVN_REVISION@@

◆ interpolate_point4d()

void interpolate_point4d ( POINT4D A,
POINT4D B,
POINT4D I,
double  F 
)

Find interpolation point I between point A and point B so that the len(AI) == len(AB)*F and I falls on AB segment.

Example:

F=0.5 : A-—I-—B F=1 : A------—B==I F=0 : A==I------—B F=.2 : A-I----—B

Definition at line 819 of file lwgeom_api.c.

References lwerror(), POINT4D::m, POINT4D::x, POINT4D::y, and POINT4D::z.

Referenced by LWGEOM_line_interpolate_point(), and ptarray_substring().

820 {
821 #if PARANOIA_LEVEL > 0
822  double absF=fabs(F);
823  if ( absF < 0 || absF > 1 )
824  {
825  lwerror("interpolate_point4d: invalid F (%g)", F);
826  }
827 #endif
828  I->x=A->x+((B->x-A->x)*F);
829  I->y=A->y+((B->y-A->y)*F);
830  I->z=A->z+((B->z-A->z)*F);
831  I->m=A->m+((B->m-A->m)*F);
832 }
double x
Definition: liblwgeom.h:351
double m
Definition: liblwgeom.h:351
double z
Definition: liblwgeom.h:351
double y
Definition: liblwgeom.h:351
void lwerror(const char *fmt,...)
Write a notice out to the error handler.
Definition: lwutil.c:102
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