public override VectorPoint Copy()
{
EllipseLinePoint point = new EllipseLinePoint(X, Y);
point.Length = Length;
point.SweepAngle = SweepAngle;
point.StartAngle = StartAngle;
point.SinXAxis = SinXAxis;
point.CosXAxis = CosXAxis;
point.CenterX = CenterX;
point.CenterY = CenterY;
point.RadiusX = RadiusX;
point.RadiusY = RadiusY;
return(point);
}
/// <summary>Handles SVG arcs.</summary>
public void EllipseArc(float rx, float ry, float xAxisRotation, float p1x, float p1y, bool largeArcFlag, bool sweepFlag)
{
// In accordance to: http://www.w3.org/TR/SVG/implnote.html#ArcOutOfRangeParameters
rx = Math.Abs(rx);
ry = Math.Abs(ry);
// If the endpoints are identical, do nothing.
if (LatestPathNode.X == p1x && LatestPathNode.Y == p1y)
{
return;
}
// If rx = 0 or ry = 0 then this arc is treated as a straight line segment joining the endpoints.
if (rx == 0f || ry == 0f)
{
LineTo(p1x, p1y);
return;
}
// Normalize rotation from deg to radians:
xAxisRotation = (xAxisRotation % 360f) * UnityEngine.Mathf.Deg2Rad;
float cosXAxis = (float)Math.Cos(xAxisRotation);
float sinXAxis = (float)Math.Sin(xAxisRotation);
// Conversion from endpoint to center parameterization
// http://www.w3.org/TR/SVG/implnote.html#ArcConversionEndpointToCenter
// #1: Compute transformed point
float dx = (LatestPathNode.X - p1x) / 2f;
float dy = (LatestPathNode.Y - p1y) / 2f;
float transformedX = (float)(cosXAxis * dx + sinXAxis * dy);
float transformedY = (float)(-sinXAxis * dx + cosXAxis * dy);
// Ensure radii are large enough
float radiiCheck = (float)(
Math.Pow(transformedX, 2f) / Math.Pow(rx, 2f) +
Math.Pow(transformedY, 2f) / Math.Pow(ry, 2f)
);
if (radiiCheck > 1)
{
rx = (float)Math.Sqrt(radiiCheck) * rx;
ry = (float)Math.Sqrt(radiiCheck) * ry;
}
// #2: Compute transformed center
float cSquareNumerator = (float)(
Math.Pow(rx, 2f) * Math.Pow(ry, 2f) -
Math.Pow(rx, 2f) * Math.Pow(transformedY, 2f) -
Math.Pow(ry, 2f) * Math.Pow(transformedX, 2f)
);
float cSquareRootDenom = (float)(
Math.Pow(rx, 2f) * Math.Pow(transformedY, 2f) +
Math.Pow(ry, 2f) * Math.Pow(transformedX, 2f)
);
float cRadicand = cSquareNumerator / cSquareRootDenom;
// Make sure this never drops below zero because of precision
cRadicand = cRadicand < 0f ? 0f : cRadicand;
float cCoef = (largeArcFlag != sweepFlag ? 1f : -1f) * (float)Math.Sqrt(cRadicand);
float transformedCenterX = cCoef * ((rx * transformedY) / ry);
float transformedCenterY = cCoef * (-(ry * transformedX) / rx);
// #3: Compute center
float centerX = (float)(
cosXAxis * transformedCenterX -
sinXAxis * transformedCenterY + ((LatestPathNode.X + p1x) / 2f)
);
float centerY = (float)(
sinXAxis * transformedCenterX +
cosXAxis * transformedCenterY + ((LatestPathNode.Y + p1y) / 2f)
);
// #4: Compute start/sweep angles
// Start angle of the elliptical arc prior to the stretch and rotate operations.
// Difference between the start and end angles
UnityEngine.Vector2 startVector = new UnityEngine.Vector2(
(transformedX - transformedCenterX) / rx,
(transformedY - transformedCenterY) / ry
);
float startAngle = AngleBetween(new UnityEngine.Vector2(1f, 0f), startVector);
UnityEngine.Vector2 endVector = new UnityEngine.Vector2(
(-transformedX - transformedCenterX) / rx,
(-transformedY - transformedCenterY) / ry
);
float sweepAngle = AngleBetween(startVector, endVector);
if (!sweepFlag && sweepAngle > 0)
{
sweepAngle -= 2f * (float)Math.PI;
}
else if (sweepFlag && sweepAngle < 0)
{
sweepAngle += 2f * (float)Math.PI;
}
// We use % instead of `mod(..)` because we want it to be -360deg to 360deg(but actually in radians)
sweepAngle %= 2f * (float)Math.PI;
// Ellipse point:
EllipseLinePoint elp = new EllipseLinePoint(p1x, p1y);
// Apply values:
elp.SweepAngle = sweepAngle;
elp.StartAngle = startAngle;
elp.SinXAxis = sinXAxis;
elp.CosXAxis = cosXAxis;
elp.CenterX = centerX;
elp.CenterY = centerY;
elp.RadiusX = rx;
elp.RadiusY = ry;
// Add it:
AddPathNode(elp);
}
