public CIE1931Point NearestContainedPoint(CIE1931Point point)
{
if (Contains(point))
{
// If this gamut already contains the point, then no adjustment is required.
return(point);
}
// Find the closest point on each line in the triangle.
CIE1931Point pAB = GetClosestPointOnLine(Red, Green, point);
CIE1931Point pAC = GetClosestPointOnLine(Red, Blue, point);
CIE1931Point pBC = GetClosestPointOnLine(Green, Blue, point);
//Get the distances per point and see which point is closer to our Point.
double dAB = GetDistanceBetweenTwoPoints(point, pAB);
double dAC = GetDistanceBetweenTwoPoints(point, pAC);
double dBC = GetDistanceBetweenTwoPoints(point, pBC);
double lowest = dAB;
CIE1931Point closestPoint = pAB;
if (dAC < lowest)
{
lowest = dAC;
closestPoint = pAC;
}
if (dBC < lowest)
{
lowest = dBC;
closestPoint = pBC;
}
return(closestPoint);
}
private static double GetDistanceBetweenTwoPoints(CIE1931Point one, CIE1931Point two)
{
double dx = one.x - two.x; // horizontal difference
double dy = one.y - two.y; // vertical difference
return(Math.Sqrt(dx * dx + dy * dy));
}
private static bool IsAbove(CIE1931Point blue, CIE1931Point red, CIE1931Point point)
{
double slope = (blue.y - red.y) / (blue.x - red.x);
double intercept = blue.y - slope * blue.x;
double minY = point.x * slope + intercept;
return(point.y >= minY);
}
private static bool IsBelow(CIE1931Point a, CIE1931Point b, CIE1931Point point)
{
double slope = (a.y - b.y) / (a.x - b.x);
double intercept = a.y - slope * a.x;
double maxY = point.x * slope + intercept;
return(point.y <= maxY);
}
public bool Contains(CIE1931Point point)
{
// Arrangement of points in color space:
//
// ^ G
// y|
// | R
// | B
// .------------------->
// x
//
return(IsBelow(Blue, Green, point) &&
IsBelow(Green, Red, point) &&
IsAbove(Red, Blue, point));
}
private static CIE1931Point GetClosestPointOnLine(CIE1931Point a, CIE1931Point b, CIE1931Point p)
{
CIE1931Point AP = new CIE1931Point(p.x - a.x, p.y - a.y);
CIE1931Point AB = new CIE1931Point(b.x - a.x, b.y - a.y);
double ab2 = AB.x * AB.x + AB.y * AB.y;
double ap_ab = AP.x * AB.x + AP.y * AB.y;
double t = ap_ab / ab2;
// Bound to ends of line between A and B.
if (t < 0.0f)
{
t = 0.0f;
}
else if (t > 1.0f)
{
t = 1.0f;
}
return(new CIE1931Point(a.x + AB.x * t, a.y + AB.y * t));
}
public CIE1931Gamut(CIE1931Point red, CIE1931Point green, CIE1931Point blue)
{
this.Red = red;
this.Green = green;
this.Blue = blue;
}