ptarray_affine()

void ptarray_affine	(	POINTARRAY *	pa,
		const AFFINE *	a
	)

Affine transform a pointarray.

Definition at line 1796 of file ptarray.c.

{
        uint32_t i;
        double x,y,z;
        POINT4D p4d;
 
        LWDEBUG(2, "lwgeom_affine_ptarray start");
 
        if ( FLAGS_GET_Z(pa->flags) )
        {
                LWDEBUG(3, " has z");
 
                for (i=0; i<pa->npoints; i++)
                {
                        getPoint4d_p(pa, i, &p4d);
                        x = p4d.x;
                        y = p4d.y;
                        z = p4d.z;
                        p4d.x = a->afac * x + a->bfac * y + a->cfac * z + a->xoff;
                        p4d.y = a->dfac * x + a->efac * y + a->ffac * z + a->yoff;
                        p4d.z = a->gfac * x + a->hfac * y + a->ifac * z + a->zoff;
                        ptarray_set_point4d(pa, i, &p4d);
 
                        LWDEBUGF(3, " POINT %g %g %g => %g %g %g", x, y, z, p4d.x, p4d.y, p4d.z);
                }
        }
        else
        {
                LWDEBUG(3, " doesn't have z");
 
                for (i=0; i<pa->npoints; i++)
                {
                        getPoint4d_p(pa, i, &p4d);
                        x = p4d.x;
                        y = p4d.y;
                        p4d.x = a->afac * x + a->bfac * y + a->xoff;
                        p4d.y = a->dfac * x + a->efac * y + a->yoff;
                        ptarray_set_point4d(pa, i, &p4d);
 
                        LWDEBUGF(3, " POINT %g %g => %g %g", x, y, p4d.x, p4d.y);
                }
        }
 
        LWDEBUG(3, "lwgeom_affine_ptarray end");
 
}

References AFFINE::afac, AFFINE::bfac, AFFINE::cfac, AFFINE::dfac, AFFINE::efac, AFFINE::ffac, POINTARRAY::flags, FLAGS_GET_Z, getPoint4d_p(), AFFINE::gfac, AFFINE::hfac, AFFINE::ifac, LWDEBUG, LWDEBUGF, POINTARRAY::npoints, ptarray_set_point4d(), POINT4D::x, pixval::x, AFFINE::xoff, POINT4D::y, pixval::y, AFFINE::yoff, POINT4D::z, and AFFINE::zoff.

Referenced by lwgeom_affine().

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