static void
fill_clipped_contour (hidGC gc, PLINE *pl, const BoxType *clip_box)
{
PLINE *pl_copy;
POLYAREA *clip_poly;
POLYAREA *piece_poly;
POLYAREA *clipped_pieces;
POLYAREA *draw_piece;
int x;
clip_poly = RectPoly (clip_box->X1, clip_box->X2,
clip_box->Y1, clip_box->Y2);
poly_CopyContour (&pl_copy, pl);
piece_poly = poly_Create ();
poly_InclContour (piece_poly, pl_copy);
x = poly_Boolean_free (piece_poly, clip_poly,
&clipped_pieces, PBO_ISECT);
if (x != err_ok || clipped_pieces == NULL)
return;
draw_piece = clipped_pieces;
do
{
/* NB: The polygon won't have any holes in it */
fill_contour (gc, draw_piece->contours);
}
while ((draw_piece = draw_piece->f) != clipped_pieces);
poly_Free (&clipped_pieces);
}
static POLYAREA *
original_poly (PolygonType * p, bool *forward)
{
PLINE *contour = NULL;
POLYAREA *np = NULL;
Cardinal n;
Vector v;
int hole = 0;
*forward = true;
if ((np = poly_Create ()) == NULL)
return NULL;
/* first make initial polygon contour */
for (n = 0; n < p->PointN; n++)
{
/* No current contour? Make a new one starting at point */
/* (or) Add point to existing contour */
v[0] = p->Points[n].X;
v[1] = p->Points[n].Y;
if (contour == NULL)
{
if ((contour = poly_NewContour (v)) == NULL)
return NULL;
}
else
{
poly_InclVertex (contour->head.prev, poly_CreateNode (v));
}
/* Is current point last in contour? If so process it. */
if (n == p->PointN - 1 ||
(hole < p->HoleIndexN && n == p->HoleIndex[hole] - 1))
{
poly_PreContour (contour, TRUE);
/* Log the direction in which the outer contour was specified */
if (hole == 0)
*forward = (contour->Flags.orient == PLF_DIR);
/* make sure it is a positive contour (outer) or negative (hole) */
if (contour->Flags.orient != (hole ? PLF_INV : PLF_DIR))
poly_InvContour (contour);
assert (contour->Flags.orient == (hole ? PLF_INV : PLF_DIR));
poly_InclContour (np, contour);
contour = NULL;
assert (poly_Valid (np));
hole++;
}
}
return np;
}
