static Arc ComputeArc(double x0, double y0, double rx, double ry, double angle, bool largeArcFlag, bool sweepFlag, double x, double y) { //from Apache2, https://xmlgraphics.apache.org/ /** * This constructs an unrotated Arc2D from the SVG specification of an * Elliptical arc. To get the final arc you need to apply a rotation * transform such as: * * AffineTransform.getRotateInstance * (angle, arc.getX()+arc.getWidth()/2, arc.getY()+arc.getHeight()/2); */ // // Elliptical arc implementation based on the SVG specification notes // // Compute the half distance between the current and the final point double dx2 = (x0 - x) / 2.0; double dy2 = (y0 - y) / 2.0; // Convert angle from degrees to radians angle = ((angle % 360.0) * Math.PI / 180f); double cosAngle = Math.Cos(angle); double sinAngle = Math.Sin(angle); // // Step 1 : Compute (x1, y1) // double x1 = (cosAngle * dx2 + sinAngle * dy2); double y1 = (-sinAngle * dx2 + cosAngle * dy2); // Ensure radii are large enough rx = Math.Abs(rx); ry = Math.Abs(ry); double Prx = rx * rx; double Pry = ry * ry; double Px1 = x1 * x1; double Py1 = y1 * y1; // check that radii are large enough double radiiCheck = Px1 / Prx + Py1 / Pry; if (radiiCheck > 1) { rx = Math.Sqrt(radiiCheck) * rx; ry = Math.Sqrt(radiiCheck) * ry; Prx = rx * rx; Pry = ry * ry; } // // Step 2 : Compute (cx1, cy1) // double sign = (largeArcFlag == sweepFlag) ? -1 : 1; double sq = ((Prx * Pry) - (Prx * Py1) - (Pry * Px1)) / ((Prx * Py1) + (Pry * Px1)); sq = (sq < 0) ? 0 : sq; double coef = (sign * Math.Sqrt(sq)); double cx1 = coef * ((rx * y1) / ry); double cy1 = coef * -((ry * x1) / rx); // // Step 3 : Compute (cx, cy) from (cx1, cy1) // double sx2 = (x0 + x) / 2.0; double sy2 = (y0 + y) / 2.0; double cx = sx2 + (cosAngle * cx1 - sinAngle * cy1); double cy = sy2 + (sinAngle * cx1 + cosAngle * cy1); // // Step 4 : Compute the angleStart (angle1) and the angleExtent (dangle) // double ux = (x1 - cx1) / rx; double uy = (y1 - cy1) / ry; double vx = (-x1 - cx1) / rx; double vy = (-y1 - cy1) / ry; double p, n; // Compute the angle start n = Math.Sqrt((ux * ux) + (uy * uy)); p = ux; // (1 * ux) + (0 * uy) sign = (uy < 0) ? -1d : 1d; double angleStart = (sign * Math.Acos(p / n)); // Math.toDegrees(sign * Math.Acos(p / n)); // Compute the angle extent n = Math.Sqrt((ux * ux + uy * uy) * (vx * vx + vy * vy)); p = ux * vx + uy * vy; sign = (ux * vy - uy * vx < 0) ? -1d : 1d; double angleExtent = (sign * Math.Acos(p / n));// Math.toDegrees(sign * Math.Acos(p / n)); if (!sweepFlag && angleExtent > 0) { angleExtent -= 360f; } else if (sweepFlag && angleExtent < 0) { angleExtent += 360f; } //angleExtent %= 360f; //angleStart %= 360f; // // We can now build the resulting Arc2D in double precision // //Arc2D.Double arc = new Arc2D.Double(); //arc.x = cx - rx; //arc.y = cy - ry; //arc.width = rx * 2.0; //arc.height = ry * 2.0; //arc.start = -angleStart; //arc.extent = -angleExtent; Arc arc = new Arc(); arc.Init(x, y, rx, ry, -(angleStart), -(angleExtent)); return(arc); }
IEnumerable <VertexData> GetVertexIter() { currentProcessingArc.UseStartEndLimit = true; currentProcessingArc.Init(bounds.Left + leftBottomRadius.x, bounds.Bottom + leftBottomRadius.y, leftBottomRadius.x, leftBottomRadius.y, Math.PI, Math.PI + Math.PI * 0.5); currentProcessingArc.SetStartEndLimit(bounds.Left, bounds.Bottom + leftBottomRadius.y, bounds.Left + leftBottomRadius.x, bounds.Bottom); foreach (VertexData vertexData in currentProcessingArc.GetVertexIter()) { if (VertexHelper.IsEmpty(vertexData.command)) { break; } yield return(vertexData); } currentProcessingArc.Init(bounds.Right - rightBottomRadius.x, bounds.Bottom + rightBottomRadius.y, rightBottomRadius.x, rightBottomRadius.y, Math.PI + Math.PI * 0.5, 0.0); currentProcessingArc.SetStartEndLimit(bounds.Right - rightBottomRadius.x, bounds.Bottom, bounds.Right, bounds.Bottom + rightBottomRadius.y); foreach (VertexData vertexData in currentProcessingArc.GetVertexIter()) { if (VertexHelper.IsMoveTo(vertexData.command)) { // skip the initial moveto continue; } if (VertexHelper.IsEmpty(vertexData.command)) { break; } yield return(vertexData); } currentProcessingArc.Init(bounds.Right - rightTopRadius.x, bounds.Top - rightTopRadius.y, rightTopRadius.x, rightTopRadius.y, 0.0, Math.PI * 0.5); currentProcessingArc.SetStartEndLimit(bounds.Right, bounds.Top - rightTopRadius.y, bounds.Right - rightTopRadius.x, bounds.Top); foreach (VertexData vertexData in currentProcessingArc.GetVertexIter()) { if (VertexHelper.IsMoveTo(vertexData.command)) { // skip the initial moveto continue; } if (VertexHelper.IsEmpty(vertexData.command)) { break; } yield return(vertexData); } currentProcessingArc.Init(bounds.Left + leftTopRadius.x, bounds.Top - leftTopRadius.y, leftTopRadius.x, leftTopRadius.y, Math.PI * 0.5, Math.PI); currentProcessingArc.SetStartEndLimit(bounds.Left - leftTopRadius.x, bounds.Top, bounds.Left, bounds.Top - leftTopRadius.y); foreach (VertexData vertexData in currentProcessingArc.GetVertexIter()) { switch (vertexData.command) { case VertexCmd.MoveTo: continue; case VertexCmd.NoMore: break; default: yield return(vertexData); break; } } yield return(new VertexData(VertexCmd.Close, (int)EndVertexOrientation.CCW, 0)); yield return(new VertexData(VertexCmd.NoMore)); }