private PtV FarthestPointToPoint(RectV rect, PointF pt)
{
return new PtV()
{
X = pt.X < rect.W / 2 ? (Func<double, double>)rect.Right : (Func<double, double>)rect.Left,
Y = pt.Y < rect.H / 2 ? (Func<double, double>)rect.Bottom : (Func<double, double>)rect.Top
};
}
private void MaxTextRegion(Size size, CircleF circle, double angle, double fratio, out float mxlen, out PointF center)
{
// ew(Ex-Width)=(len*fratio)/2
// half-rect
// { w=ew+len*|cosa|/2
// h=ew+len*|sina|/2 }
// { c0=...
// c1=... }
double vx = Math.Cos(angle);
double vy = Math.Sin(angle);
double c0 = (fratio + Math.Abs(vx)) / 2;
double c1 = (fratio + Math.Abs(vy)) / 2;
double mxlenx = Math.Min(size.Width / (2 * c0), size.Height / (2 * c1));
RectV rect = new RectV()
{
C0 = c0, C1 = c1, W = size.Width, H = size.Height
};
PtV fp = FarthestPointToPoint(rect, circle.Center);
float cx = circle.Center.X, cy = circle.Center.Y;
double l = 0, r = mxlenx;
Point2D c = new Point2D(cx, cy);
for (int i = 0; i < 16; i++)
{
double mid = (l + r) / 2;
double px = fp.X(mid);
double py = fp.Y(mid);
double px0 = px + vx * mid / 2;
double py0 = py + vy * mid / 2;
double px1 = px - vx * mid / 2;
double py1 = py - vy * mid / 2;
Line2D line = new Line2D(new Point2D(px0, py0), new Point2D(px1, py1));
Point2D cp = line.ClosestPointTo(c, true);
if (cp.DistanceTo(c) < circle.Radius + mid * fratio / 2)
{
r = mid;
}
else
{
l = mid;
}
}
mxlenx = (l + r) / 2;
mxlen = (float)mxlenx;
center = new PointF((float)fp.X(mxlenx), (float)fp.Y(mxlenx));
}
