public IMask GetQuarterFadedCircle(int radius, float fade, IInterpolation interpolation)
{
if (radius < 0 || fade > 1 || fade < 0)
{
throw new ArgumentException();
}
int fadeBegin = (int)(radius * (1 - fade));
var brushmask = new Mask(new Vector2(radius, radius));
for (int y = 0; y < radius; y++)
{
var li = (int)JryMath.Sqrt(radius * radius - (radius - y) * (radius - y));
for (int x = 0; x < li; x++)
{
var yCor = radius - y;
float val = 1;
var dis = JryMath.Sqrt(x * x + yCor * yCor);
if (dis > fadeBegin)
{
val = interpolation.Interpolate(1, 0, (dis - fadeBegin) / (radius - fadeBegin));
}
brushmask[x, yCor - 1] = val;
}
}
return(brushmask);
}
public Vector2 getParabalaeIntersection(Parabola left, Parabola right, double directixY)
{
if (left == null || right == null || left.Site == right.Site)
{
throw new Exception("NoIntersectoinFound");
}
double denominator1 = 2.0f * (left.Site.Y - directixY);
//#warning quickfix
if (denominator1 == 0)
{
denominator1 = 0.000001;
}
double a1 = 1.0f / denominator1;
double b1 = -2.0f * left.Site.X / denominator1;
double c1 = ((left.Site.X * left.Site.X) + (left.Site.Y * left.Site.Y) - (directixY * directixY))
/ denominator1;
//y + dp / 4 + px * px / dp
double denominator2 = 2.0f * (right.Site.Y - directixY);
//#warning quickfix
if (denominator2 == 0)
{
denominator2 = 0.000001;
}
double a2 = 1.0f / denominator2;
double b2 = -2.0f * right.Site.X / denominator2;
double c2 = ((right.Site.X * right.Site.X) + (right.Site.Y * right.Site.Y) - (directixY * directixY))
/ denominator2;
double a = a1 - a2;
double b = b1 - b2;
double c = c1 - c2;
double x1 = 0, x2 = 0;
if (a == 0)// 0 = bx +c
{
x1 = -c / b;
x2 = x1;
}
else //0 = ax^2 + bx + c
{
double disc = b * b - 4 * a * c;
if (disc < 0)// when everything is ok. this case become imposible
{
throw new InvalidOperationException("Negative discriminant root not found in real domain");
}
x1 = (-b + JryMath.Sqrt(disc)) / (2 * a);
x2 = (-b - JryMath.Sqrt(disc)) / (2 * a);
}
double x;
if (left.Site.Y < right.Site.Y)
{
x = JryMath.Max(x1, x2);
}
else
{
x = JryMath.Min(x1, x2);
}
double y;
// i have chosen to use left parabola to get Y coor;
y = a1 * x * x + b1 * x + c1;
return(new Vector2((float)x, (float)y));
}
