private double dist(PointFortune s, PointFortune t)
{
double dx, dy;
dx = s.X - t.X;
dy = s.Y - t.Y;
return(Convert.ToSingle(Math.Sqrt(dx * dx + dy * dy)));
}
// create a new site where the HalfEdges el1 and el2 intersect - note that
// the Point in the argument list is not used, don't know why it's there
private PointFortune intersect(Halfedge el1, Halfedge el2)
{
EdgeF e1, e2, e;
Halfedge el;
double d, xint, yint;
bool right_of_site;
PointFortune v; // vertex
e1 = el1.ELedge;
e2 = el2.ELedge;
if (e1 == null || e2 == null)
{
return(null);
}
// if the two edges bisect the same parent, return null
if (e1.reg[1] == e2.reg[1])
{
return(null);
}
d = e1.a * e2.b - e1.b * e2.a;
if (-1.0e-10 < d && d < 1.0e-10)
{
return(null);
}
xint = (e1.c * e2.b - e2.c * e1.b) / d;
yint = (e2.c * e1.a - e1.c * e2.a) / d;
if ((e1.reg[1].Y < e2.reg[1].Y) ||
(e1.reg[1].Y == e2.reg[1].Y && e1.reg[1].X < e2.reg[1].X))
{
el = el1;
e = e1;
}
else
{
el = el2;
e = e2;
}
right_of_site = xint >= e.reg[1].X;
if ((right_of_site && el.ELpm == LE) ||
(!right_of_site && el.ELpm == RE))
{
return(null);
}
// create a new site at the point of intersection - this is a new vector
// event waiting to happen
v = new PointFortune();
v.X = xint;
v.Y = yint;
return(v);
}
private void endpoint(EdgeF e, int lr, PointFortune s)
{
e.ep[lr] = s;
if (e.ep[RE - lr] == null)
{
return;
}
clip_line(e);
}
List <EdgeFortune> MakeVoronoiGraph(List <PointF> myListPoints, int width, int height)
{
List <PointFortune> listPointsFortune = new List <PointFortune>();
for (int i = 0; i < myListPoints.Count; i++)
{
listPointsFortune.Add(new PointFortune(myListPoints[i].X, myListPoints[i].Y, i));
}
PointFortune max = new PointFortune(0, 0, 0);
PointFortune min = new PointFortune(width, height, 0);
return(voronoi.GenerateVoronoi(listPointsFortune));
}
private PointFortune PQ_min()
{
PointFortune answer = new PointFortune();
while (PQhash[PQmin].PQnext == null)
{
PQmin++;
}
answer.X = PQhash[PQmin].PQnext.vertex.X;
answer.Y = PQhash[PQmin].PQnext.ystar;
return(answer);
}
private void pushGraphEdge(PointFortune leftPointFortune, PointFortune rightPointFortune, double x1, double y1, double x2, double y2)
{
EdgeFortune newEdge = new EdgeFortune();
allEdges.Add(newEdge);
newEdge.x1 = x1;
newEdge.y1 = y1;
newEdge.x2 = x2;
newEdge.y2 = y2;
newEdge.PointIndex1 = leftPointFortune.IndexInList;
newEdge.PointIndex2 = rightPointFortune.IndexInList;
}
// push the HalfEdge into the ordered linked list of pointCloud
private void PQinsert(Halfedge he, PointFortune v, double offset)
{
Halfedge last, next;
he.vertex = v;
he.ystar = (double)(v.Y + offset);
last = PQhash[PQbucket(he)];
while
(
(next = last.PQnext) != null
&&
(he.ystar > next.ystar || (he.ystar == next.ystar && v.X > next.vertex.X))
)
{
last = next;
}
he.PQnext = last.PQnext;
last.PQnext = he;
PQcount++;
}
private EdgeF bisect(PointFortune s1, PointFortune s2)
{
double dx, dy, adx, ady;
EdgeF newedge;
newedge = new EdgeF();
newedge.reg[0] = s1;
newedge.reg[1] = s2;
newedge.ep[0] = null;
newedge.ep[1] = null;
dx = s2.X - s1.X;
dy = s2.Y - s1.Y;
adx = dx > 0 ? dx : -dx;
ady = dy > 0 ? dy : -dy;
newedge.c = (double)(s1.X * dx + s1.Y * dy + (dx * dx + dy * dy) * 0.5);
if (adx > ady)
{
newedge.a = 1.0f;
newedge.b = dy / dx;
newedge.c /= dx;
}
else
{
newedge.a = dx / dy;
newedge.b = 1.0f;
newedge.c /= dy;
}
newedge.edgenbr = nedges;
nedges++;
return(newedge);
}
private void CalculateMinMax(ref PointFortune max, ref PointFortune min)
{
if (points.Count < 1)
{
return;
}
double xMax = points[0].X;
double yMax = points[0].Y;
double xMin = points[0].X;
double yMin = points[0].Y;
foreach (PointFortune ver in points)
{
if (ver.X > xMax)
{
xMax = ver.X;
}
if (ver.Y > yMax)
{
yMax = ver.Y;
}
if (ver.X < xMin)
{
xMin = ver.X;
}
if (ver.Y < yMin)
{
yMin = ver.Y;
}
}
max.X = xMax;
max.Y = yMax;
min.X = xMin;
min.Y = yMin;
}
private void sortNode()
{
numberPointsStart = points.Count;
xmin = points[0].X;
ymin = points[0].Y;
xmax = points[0].X;
ymax = points[0].Y;
for (int i = 0; i < numberPointsStart; i++)
{
PointFortune p = points[i];
if (p.X < xmin)
{
xmin = p.X;
}
else if (p.X > xmax)
{
xmax = p.X;
}
if (p.Y < ymin)
{
ymin = p.Y;
}
else if (p.Y > ymax)
{
ymax = p.Y;
}
}
points.Sort(new PointFortuneSorterYX());
deltax = xmax - xmin;
deltay = ymax - ymin;
}
/// <summary>
/// Generate a Voronoi List of Edges
/// </summary>
/// <param name="mypoints"></param>
/// <param name="minX: The minimum X of the bounding box around the voronoi"></param>
/// <param name="maxX: The maximum X of the bounding box around the voronoi"></param>
/// <param name="minY: The minimum Y of the bounding box around the voronoi"></param>
/// <param name="maxY: The maximum Y of the bounding box around the voronoi"></param>
/// <returns></returns>
public List <EdgeFortune> GenerateVoronoi(List <PointFortune> mypoints)
{
this.points = mypoints;
PointFortune max = new PointFortune();
PointFortune min = new PointFortune();
CalculateMinMax(ref max, ref min);
sort();
//SwapValues(ref minX, ref maxX, ref minY, ref maxY);
borderMinX = min.X;
borderMinY = min.Y;
borderMaxX = max.X;
borderMaxY = max.Y;
siteidx = 0;
calculateVoronoi();
return(allEdges);
}
/*
* implicit parameters: nsites, sqrt_nsites, xmin, xmax, ymin, ymax, deltax,
* deltay (can all be estimates). Performance suffers if they are wrong;
* better to make nsites, deltax, and deltay too big than too small. (?)
*/
private bool calculateVoronoi()
{
PointFortune newsite, bot, top, temp, p;
PointFortune v;
PointFortune newintstar = null;
int pm;
Halfedge leftEdge, rightEdge, llHalfedge, rrHalfedge, bisector;
EdgeF e;
PQinitialize();
ELinitialize();
bottomsite = nextone();
newsite = nextone();
while (true)
{
if (!PQempty())
{
newintstar = PQ_min();
}
// if the lowest site has a smaller y value than the lowest vector
// intersection,
// process the site otherwise process the vector intersection
if (newsite != null && (PQempty() ||
newsite.Y < newintstar.Y ||
(newsite.Y == newintstar.Y &&
newsite.X < newintstar.X)))
{
/* new site is smallest -this is a site event */
// get the first HalfEdge to the LEFT of the new site
leftEdge = ELleftbnd((newsite));
// get the first HalfEdge to the RIGHT of the new site
rightEdge = ELright(leftEdge);
// if this halfedge has no edge,bot =bottom site (whatever that
// is)
bot = rightreg(leftEdge);
// create a new edge that bisects
e = bisect(bot, newsite);
// create a new HalfEdge, setting its ELpm field to 0
bisector = HEcreate(e, LE);
// insert this new bisector edge between the left and right
// vectors in a linked list
ELinsert(leftEdge, bisector);
// if the new bisector intersects with the left edge,
// remove the left edge's vertex, and put in the new one
if ((p = intersect(leftEdge, bisector)) != null)
{
PQdelete(leftEdge);
PQinsert(leftEdge, p, dist(p, newsite));
}
leftEdge = bisector;
// create a new HalfEdge, setting its ELpm field to 1
bisector = HEcreate(e, RE);
// insert the new HE to the right of the original bisector
// earlier in the IF stmt
ELinsert(leftEdge, bisector);
// if this new bisector intersects with the new HalfEdge
if ((p = intersect(bisector, rightEdge)) != null)
{
// push the HE into the ordered linked list of pointCloud
PQinsert(bisector, p, dist(p, newsite));
}
newsite = nextone();
}
else if (!PQempty())
/* intersection is smallest - this is a vector event */
{
// pop the HalfEdge with the lowest vector off the ordered list
// of vectors
leftEdge = PQextractmin();
// get the HalfEdge to the left of the above HE
llHalfedge = ELleft(leftEdge);
// get the HalfEdge to the right of the above HE
rightEdge = ELright(leftEdge);
// get the HalfEdge to the right of the HE to the right of the
// lowest HE
rrHalfedge = ELright(rightEdge);
// get the PointFortune to the left of the left HE which it bisects
bot = leftreg(leftEdge);
// get the PointFortune to the right of the right HE which it bisects
top = rightreg(rightEdge);
v = leftEdge.vertex; // get the vertex that caused this event
makevertex(v); // set the vertex number - couldn't do this
// earlier since we didn't know when it would be processed
endpoint(leftEdge.ELedge, leftEdge.ELpm, v);
// set the endpoint of
// the left HalfEdge to be this vector
endpoint(rightEdge.ELedge, rightEdge.ELpm, v);
// set the endpoint of the right HalfEdge to
// be this vector
ELdelete(leftEdge); // mark the lowest HE for
// deletion - can't delete yet because there might be pointers
// to it in Hash Map
PQdelete(rightEdge);
// remove all vertex events to do with the right HE
ELdelete(rightEdge); // mark the right HE for
// deletion - can't delete yet because there might be pointers
// to it in Hash Map
pm = LE; // set the pm variable to zero
if (bot.Y > top.Y)
// if the site to the left of the event is higher than the
// PointFortune
{ // to the right of it, then swap them and set the 'pm'
// variable to 1
temp = bot;
bot = top;
top = temp;
pm = RE;
}
e = bisect(bot, top); // create an Edge (or line)
// that is between the two PointFortunes. This creates the formula of
// the line, and assigns a line number to it
bisector = HEcreate(e, pm); // create a HE from the Edge 'e',
// and make it point to that edge
// with its ELedge field
ELinsert(llHalfedge, bisector); // insert the new bisector to the
// right of the left HE
endpoint(e, RE - pm, v); // set one endpoint to the new edge
// to be the vector point 'v'.
// If the site to the left of this bisector is higher than the
// right PointFortune, then this endpoint
// is put in position 0; otherwise in pos 1
// if left HE and the new bisector intersect, then delete
// the left HE, and reinsert it
if ((p = intersect(llHalfedge, bisector)) != null)
{
PQdelete(llHalfedge);
PQinsert(llHalfedge, p, dist(p, bot));
}
// if right HE and the new bisector intersect, then
// reinsert it
if ((p = intersect(bisector, rrHalfedge)) != null)
{
PQinsert(bisector, p, dist(p, bot));
}
}
else
{
break;
}
}
for (leftEdge = ELright(ELleftend); leftEdge != ELrightend; leftEdge = ELright(leftEdge))
{
e = leftEdge.ELedge;
clip_line(e);
}
return(true);
}
/* returns true if p is to right of halfedge e */
private bool right_of(Halfedge el, PointFortune p)
{
EdgeF e;
PointFortune topsite;
bool right_of_site;
bool above, fast;
double dxp, dyp, dxs, t1, t2, t3, yl;
e = el.ELedge;
topsite = e.reg[1];
if (p.X > topsite.X)
{
right_of_site = true;
}
else
{
right_of_site = false;
}
if (right_of_site && el.ELpm == LE)
{
return(true);
}
if (!right_of_site && el.ELpm == RE)
{
return(false);
}
if (e.a == 1)
{
dxp = p.X - topsite.X;
dyp = p.Y - topsite.Y;
fast = false;
if ((!right_of_site & (e.b < 0)) | (right_of_site & (e.b >= 0)))
{
above = dyp >= e.b * dxp;
fast = above;
}
else
{
above = p.X + p.Y * e.b > e.c;
if (e.b < 0)
{
above = !above;
}
if (!above)
{
fast = true;
}
}
if (!fast)
{
dxs = topsite.X - (e.reg[0]).X;
above = e.b * (dxp * dxp - dyp * dyp)
< dxs * dyp * (1 + 2 * dxp / dxs + e.b * e.b);
if (e.b < 0)
{
above = !above;
}
}
}
else // e.b == 1.0
{
yl = e.c - e.a * p.X;
t1 = p.Y - yl;
t2 = p.X - topsite.X;
t3 = yl - topsite.Y;
above = t1 * t1 > t2 * t2 + t3 * t3;
}
return(el.ELpm == LE ? above : !above);
}
private Halfedge ELleftbnd(PointFortune p)
{
int bucket;
Halfedge he;
/* Use hash table to get close to desired halfedge */
// use the hash function to find the place in the hash map that this
// HalfEdge should be
bucket = (int)((p.X - xmin) / deltax * ELhashsize);
// make sure that the bucket position is within the range of the hash
// array
if (bucket < 0)
{
bucket = 0;
}
if (bucket >= ELhashsize)
{
bucket = ELhashsize - 1;
}
he = ELgethash(bucket);
// if the HE isn't found, search backwards and forwards in the hash map
// for the first non-null entry
if (he == null)
{
for (int i = 1; i < ELhashsize; i++)
{
if ((he = ELgethash(bucket - i)) != null)
{
break;
}
if ((he = ELgethash(bucket + i)) != null)
{
break;
}
}
}
/* Now search linear list of halfedges for the correct one */
if (he == ELleftend || (he != ELrightend && right_of(he, p)))
{
// keep going right on the list until either the end is reached, or
// you find the 1st edge which the point isn't to the right of
do
{
he = he.ELright;
}while (he != ELrightend && right_of(he, p));
he = he.ELleft;
}
else
// if the point is to the left of the HalfEdge, then search left for
// the HE just to the left of the point
{
do
{
he = he.ELleft;
}while (he != ELleftend && !right_of(he, p));
}
/* Update hash table and reference counts */
if (bucket > 0 && bucket < ELhashsize - 1)
{
ELhash[bucket] = he;
}
return(he);
}
private void makevertex(PointFortune v)
{
v.IndexInList = numberPoints;
numberPoints++;
}
