LWPOLY* lwpoly_grid(const LWPOLY *poly, const gridspec *grid)
{
LWPOLY *opoly;
int ri;
#if 0
/*
* TODO: control this assertion
* it is assumed that, since the grid size will be a pixel,
* a visible ring should show at least a white pixel inside,
* thus, for a square, that would be grid_xsize*grid_ysize
*/
double minvisiblearea = grid->xsize * grid->ysize;
#endif
LWDEBUGF(3, "lwpoly_grid: applying grid to polygon with %d rings", poly->nrings);
opoly = lwpoly_construct_empty(poly->srid, lwgeom_has_z((LWGEOM*)poly), lwgeom_has_m((LWGEOM*)poly));
for (ri=0; ri<poly->nrings; ri++)
{
POINTARRAY *ring = poly->rings[ri];
POINTARRAY *newring;
newring = ptarray_grid(ring, grid);
/* Skip ring if not composed by at least 4 pts (3 segments) */
if ( newring->npoints < 4 )
{
ptarray_free(newring);
LWDEBUGF(3, "grid_polygon3d: ring%d skipped ( <4 pts )", ri);
if ( ri ) continue;
else break; /* this is the external ring, no need to work on holes */
}
if ( ! lwpoly_add_ring(opoly, newring) )
{
lwerror("lwpoly_grid, memory error");
return NULL;
}
}
LWDEBUGF(3, "lwpoly_grid: simplified polygon with %d rings", opoly->nrings);
if ( ! opoly->nrings )
{
lwpoly_free(opoly);
return NULL;
}
return opoly;
}
LWPOINT *
lwpoint_grid(LWPOINT *point, gridspec *grid)
{
LWPOINT *opoint;
POINTARRAY *opa;
opa = ptarray_grid(point->point, grid);
/* TODO: grid bounding box ? */
opoint = lwpoint_construct(point->srid, NULL, opa);
POSTGIS_DEBUG(2, "lwpoint_grid called");
return opoint;
}
LWCIRCSTRING *
lwcirc_grid(LWCIRCSTRING *line, gridspec *grid)
{
LWCIRCSTRING *oline;
POINTARRAY *opa;
opa = ptarray_grid(line->points, grid);
/* Skip line3d with less then 2 points */
if ( opa->npoints < 2 ) return NULL;
/* TODO: grid bounding box... */
oline = lwcircstring_construct(line->srid, NULL, opa);
return oline;
}
LWPOLY *
lwpoly_grid(LWPOLY *poly, gridspec *grid)
{
LWPOLY *opoly;
int ri;
POINTARRAY **newrings = NULL;
int nrings = 0;
double minvisiblearea;
/*
* TODO: control this assertion
* it is assumed that, since the grid size will be a pixel,
* a visible ring should show at least a white pixel inside,
* thus, for a square, that would be grid_xsize*grid_ysize
*/
minvisiblearea = grid->xsize * grid->ysize;
nrings = 0;
POSTGIS_DEBUGF(3, "grid_polygon3d: applying grid to polygon with %d rings",
poly->nrings);
for (ri=0; ri<poly->nrings; ri++)
{
POINTARRAY *ring = poly->rings[ri];
POINTARRAY *newring;
#if POSTGIS_DEBUG_LEVEL >= 4
POINT2D p1, p2;
getPoint2d_p(ring, 0, &p1);
getPoint2d_p(ring, ring->npoints-1, &p2);
if ( ! SAMEPOINT(&p1, &p2) )
POSTGIS_DEBUG(4, "Before gridding: first point != last point");
#endif
newring = ptarray_grid(ring, grid);
/* Skip ring if not composed by at least 4 pts (3 segments) */
if ( newring->npoints < 4 )
{
pfree(newring);
POSTGIS_DEBUGF(3, "grid_polygon3d: ring%d skipped ( <4 pts )", ri);
if ( ri ) continue;
else break; /* this is the external ring, no need to work on holes */
}
#if POSTGIS_DEBUG_LEVEL >= 4
getPoint2d_p(newring, 0, &p1);
getPoint2d_p(newring, newring->npoints-1, &p2);
if ( ! SAMEPOINT(&p1, &p2) )
POSTGIS_DEBUG(4, "After gridding: first point != last point");
#endif
POSTGIS_DEBUGF(3, "grid_polygon3d: ring%d simplified from %d to %d points", ri,
ring->npoints, newring->npoints);
/*
* Add ring to simplified ring array
* (TODO: dinamic allocation of pts_per_ring)
*/
if ( ! nrings )
{
newrings = palloc(sizeof(POINTARRAY *));
}
else
{
newrings = repalloc(newrings, sizeof(POINTARRAY *)*(nrings+1));
}
if ( ! newrings )
{
elog(ERROR, "Out of virtual memory");
return NULL;
}
newrings[nrings++] = newring;
}
POSTGIS_DEBUGF(3, "grid_polygon3d: simplified polygon with %d rings", nrings);
if ( ! nrings ) return NULL;
opoly = lwpoly_construct(poly->srid, NULL, nrings, newrings);
return opoly;
}
