/// <summary>
/// Convex Hull compute.
/// </summary>
/// <param name="points">The source image points.</param>
/// <param name="startPoints"></param>
/// <param name="endPoints"></param>
private static void ConvexhullCompute(ref Point[] srcPoints,ref List<Point>startPoints, ref List<Point> endPoints)
{
Point start;
Point end;
double a = 0, b = 0;
int signa = 0, signb = 0;
int max = srcPoints.Length;
double temp = 0.0;
int t = 0;
double tx = 0.0;
for (int i = 0; i < max; i++)
{
start = srcPoints[i];
for (int k = i + 1; k < max; k++)
{
end = srcPoints[k];
if (start.X == end.X)
{
for (int j = 0; j < max; j++)
{
if ((!(signa > 0 && signb > 0)) && (j != i && j != k))
{
t = srcPoints[j].X;
if (t > start.X)
signa++;
if (t < start.X)
signb++;
}
}
}
else
{
a = (double)(end.Y - start.Y) / (double)(end.X - start.X);
b = (double)start.Y - (double)start.X * a;
for (int j = 0; j < max; j++)
{
if ((!(signa > 0 && signb > 0)) && (j != i && j != k))
{
temp = a * (double)srcPoints[j].X + b;
tx = (double)srcPoints[j].Y;
if (temp > tx)
signa++;
if (temp < tx)
signb++;
}
}
}
if (signa * signb == 0)
{
startPoints.Add(start);
endPoints.Add(end);
}
signb = 0;
signa = 0;
}
}
}
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