static void test_lwpoint_set_ordinate(void)
{
POINT4D p;
p.x = 0.0;
p.y = 0.0;
p.z = 0.0;
p.m = 0.0;
lwpoint_set_ordinate(&p, 'X', 1.5);
CU_ASSERT_EQUAL( p.x, 1.5 );
lwpoint_set_ordinate(&p, 'M', 2.5);
CU_ASSERT_EQUAL( p.m, 2.5 );
lwpoint_set_ordinate(&p, 'Z', 3.5);
CU_ASSERT_EQUAL( p.z, 3.5 );
}
/**
* Given two points, a dimensionality, an ordinate, and an interpolation value
* generate a new point that is proportionally between the input points,
* using the values in the provided dimension as the scaling factors.
*/
int point_interpolate(const POINT4D *p1, const POINT4D *p2, POINT4D *p, int hasz, int hasm, char ordinate, double interpolation_value)
{
static char* dims = "XYZM";
double p1_value = lwpoint_get_ordinate(p1, ordinate);
double p2_value = lwpoint_get_ordinate(p2, ordinate);
double proportion;
int i = 0;
if ( ! ( ordinate == 'X' || ordinate == 'Y' || ordinate == 'Z' || ordinate == 'M' ) )
{
lwerror("Cannot set %c ordinate.", ordinate);
return 0;
}
if ( FP_MIN(p1_value, p2_value) > interpolation_value ||
FP_MAX(p1_value, p2_value) < interpolation_value )
{
lwerror("Cannot interpolate to a value (%g) not between the input points (%g, %g).", interpolation_value, p1_value, p2_value);
return 0;
}
proportion = fabs((interpolation_value - p1_value) / (p2_value - p1_value));
for ( i = 0; i < 4; i++ )
{
double newordinate = 0.0;
if ( dims[i] == 'Z' && ! hasz ) continue;
if ( dims[i] == 'M' && ! hasm ) continue;
p1_value = lwpoint_get_ordinate(p1, dims[i]);
p2_value = lwpoint_get_ordinate(p2, dims[i]);
newordinate = p1_value + proportion * (p2_value - p1_value);
lwpoint_set_ordinate(p, dims[i], newordinate);
LWDEBUGF(4, " clip ordinate(%c) p1_value(%g) p2_value(%g) proportion(%g) newordinate(%g) ", dims[i], p1_value, p2_value, proportion, newordinate );
}
return 1;
}
