inT16 POLY_BLOCK::winding_number(const ICOORD &point) {
inT16 count; //winding count
ICOORD pt; //current point
ICOORD vec; //point to current point
ICOORD vvec; //current point to next point
inT32 cross; //cross product
ICOORDELT_IT it = &vertices; //iterator
count = 0;
do {
pt = *it.data ();
vec = pt - point;
vvec = *it.data_relative (1) - pt;
//crossing the line
if (vec.y () <= 0 && vec.y () + vvec.y () > 0) {
cross = vec * vvec; //cross product
if (cross > 0)
count++; //crossing right half
else if (cross == 0)
return INTERSECTING; //going through point
}
else if (vec.y () > 0 && vec.y () + vvec.y () <= 0) {
cross = vec * vvec;
if (cross < 0)
count--; //crossing back
else if (cross == 0)
return INTERSECTING; //illegal
}
else if (vec.y () == 0 && vec.x () == 0)
return INTERSECTING;
it.forward ();
}
while (!it.at_first ());
return count; //winding number
}
void POLY_BLOCK::compute_bb() { //constructor
ICOORD ibl, itr; //integer bb
ICOORD botleft; //bounding box
ICOORD topright;
ICOORD pos; //current pos;
ICOORDELT_IT pts = &vertices; //iterator
botleft = *pts.data ();
topright = botleft;
do {
pos = *pts.data ();
if (pos.x () < botleft.x ())
//get bounding box
botleft = ICOORD (pos.x (), botleft.y ());
if (pos.y () < botleft.y ())
botleft = ICOORD (botleft.x (), pos.y ());
if (pos.x () > topright.x ())
topright = ICOORD (pos.x (), topright.y ());
if (pos.y () > topright.y ())
topright = ICOORD (topright.x (), pos.y ());
pts.forward ();
}
while (!pts.at_first ());
ibl = ICOORD (botleft.x (), botleft.y ());
itr = ICOORD (topright.x (), topright.y ());
box = TBOX (ibl, itr);
}
void POLY_BLOCK::move(ICOORD shift) {
ICOORDELT *pt; //current point
ICOORDELT_IT pts = &vertices; //iterator
do {
pt = pts.data ();
*pt += shift;
pts.forward ();
}
while (!pts.at_first ());
compute_bb();
}
void POLY_BLOCK::reflect_in_y_axis() {
ICOORDELT *pt; // current point
ICOORDELT_IT pts = &vertices; // Iterator.
do {
pt = pts.data();
pt->set_x(-pt->x());
pts.forward();
}
while (!pts.at_first());
compute_bb();
}
BOOL8 POLY_BLOCK::overlap( // do polys overlap
POLY_BLOCK *other) {
inT16 count; //winding count
ICOORDELT_IT it = &vertices; //iterator
ICOORD vertex;
if (!box.overlap (*(other->bounding_box ())))
return FALSE; //can't be any overlap
/* see if a vertex of this is inside other */
do {
vertex = *it.data ();
//get winding number
count = other->winding_number (vertex);
if (count != INTERSECTING)
if (count != 0)
return (TRUE);
it.forward ();
}
while (!it.at_first ());
/* see if a vertex of other is inside this */
//switch lists
it.set_to_list (other->points ());
do {
vertex = *it.data ();
//try other way round
count = winding_number (vertex);
if (count != INTERSECTING)
if (count != 0)
return (TRUE);
it.forward ();
}
while (!it.at_first ());
return FALSE;
}
BOOL8 POLY_BLOCK::contains( //other outline
POLY_BLOCK *other) {
inT16 count; //winding count
ICOORDELT_IT it = &vertices; //iterator
ICOORD vertex;
if (!box.overlap (*(other->bounding_box ())))
return FALSE; //can't be contained
/* check that no vertex of this is inside other */
do {
vertex = *it.data ();
//get winding number
count = other->winding_number (vertex);
if (count != INTERSECTING)
if (count != 0)
return (FALSE);
it.forward ();
}
while (!it.at_first ());
/* check that all vertices of other are inside this */
//switch lists
it.set_to_list (other->points ());
do {
vertex = *it.data ();
//try other way round
count = winding_number (vertex);
if (count != INTERSECTING)
if (count == 0)
return (FALSE);
it.forward ();
}
while (!it.at_first ());
return TRUE;
}
void POLY_BLOCK::rotate(FCOORD rotation) {
FCOORD pos; //current pos;
ICOORDELT *pt; //current point
ICOORDELT_IT pts = &vertices; //iterator
do {
pt = pts.data ();
pos.set_x (pt->x ());
pos.set_y (pt->y ());
pos.rotate (rotation);
pt->set_x ((inT16) (floor (pos.x () + 0.5)));
pt->set_y ((inT16) (floor (pos.y () + 0.5)));
pts.forward ();
}
while (!pts.at_first ());
compute_bb();
}
