java.awt.geom.CubicCurve2D#getY2 ( )源码实例Demo

/**
 * Report the half-way point on Bézier curve.
 *
 * @return the middle of the curve arc
 */
public Point2D getMiddlePoint ()
{
    CubicCurve2D c = getCurve();

    return new Point2D.Double(
            (c.getX1() + (3 * c.getCtrlX1()) + (3 * c.getCtrlX2()) + c.getX2()) / 8,
            (c.getY1() + (3 * c.getCtrlY1()) + (3 * c.getCtrlY2()) + c.getY2()) / 8);
}
 

CubicFacade (CubicCurve2D curve)
{
    this.x1 = curve.getX1();
    this.y1 = curve.getY1();
    this.ctrlx1 = curve.getCtrlX1();
    this.ctrly1 = curve.getCtrlY1();
    this.ctrlx2 = curve.getCtrlX2();
    this.ctrly2 = curve.getCtrlY2();
    this.x2 = curve.getX2();
    this.y2 = curve.getY2();
}
 

/**
 * Report whether the provided curve is below the notes (turned
 * upwards) or above the notes (turned downwards).
 *
 * @param curve the provided curve to check
 * @return true if below, false if above
 */
private static boolean isBelow (CubicCurve2D curve)
{
    // Determine arc orientation (above or below)
    final double DX = curve.getX2() - curve.getX1();
    final double DY = curve.getY2() - curve.getY1();
    final double power = (curve.getCtrlX1() * DY)
                         - (curve.getCtrlY1() * DX) - (curve.getX1() * DY)
                         + (curve.getY1() * DX);

    return power < 0;
}
 

/**
 * Report the left-to-right Bézier curve which best approximates the slur.
 * <p>
 * It is built by combining the left half (point &amp; control point) of left circle curve and
 * the right half (control point &amp; point) of right circle curve.
 * Vectors from point to related control point are applied a ratio extension so that curve
 * middle point (M) fits on slur middle point (M').
 * We apply the same ratio on both vectors, which may not be the best choice but that's enough
 * for a first version.
 * On a bezier curve, naming P the middle point of segment (P1,P2) and C the middle point of
 * segment (CP1,CP2), we always have vector PC = 4/3 of vector PM.
 * So, (PC' - PC) = 4/3 (PM' - PM) or (ratio - 1) * PC = 4/3 * deltaM, which gives ratio value.
 *
 * @return the bezier curve
 */
public CubicCurve2D getCurve ()
{
    if (curve == null) {
        Model leftModel = getSideModel(true);
        Model rightModel = getSideModel(false);

        if ((leftModel == null) || (rightModel == null)) {
            ///logger.warn("No side circle");
            return null;
        }

        // Assume we have circle models on both ends
        if (!(leftModel instanceof CircleModel) || !(rightModel instanceof CircleModel)) {
            return null;
        }

        CubicCurve2D left = (CubicCurve2D) leftModel.getCurve();
        CubicCurve2D right = (CubicCurve2D) rightModel.getCurve();

        if (left == right) {
            curve = left;
        } else {
            double x1 = left.getX1();
            double y1 = left.getY1();
            double cx1 = left.getCtrlX1();
            double cy1 = left.getCtrlY1();
            double cx2 = right.getCtrlX2();
            double cy2 = right.getCtrlY2();
            double x2 = right.getX2();
            double y2 = right.getY2();

            // Compute affinity ratio out of mid point translation
            Point midPt = points.get(points.size() / 2); // Approximately
            double mx = (x1 + x2 + (3 * (cx1 + cx2))) / 8;
            double my = (y1 + y2 + (3 * (cy1 + cy2))) / 8;
            double deltaM = Math.hypot(midPt.x - mx, midPt.y - my);
            double pc = Math.hypot((cx1 + cx2) - (x1 + x2), (cy1 + cy2) - (y1 + y2)) / 2;
            double ratio = 1 + ((4 * deltaM) / (3 * pc));

            // Apply ratio on vectors to control points
            curve = new CubicCurve2D.Double(
                    x1,
                    y1,
                    x1 + (ratio * (cx1 - x1)), // cx1'
                    y1 + (ratio * (cy1 - y1)), // cy1'
                    x2 + (ratio * (cx2 - x2)), // cx2'
                    y2 + (ratio * (cy2 - y2)), // cy2'
                    x2,
                    y2);
        }
    }

    return curve;
}
 

/**
 * Report the point on the curve, located at t = 1-t = 0.5.
 * It splits the curve length equally.
 * P: middle of segment P1..P2
 * C: middle of segment CP1..CP2
 * M: middle of curve
 * PM = 3/4 * PC
 *
 * @param c the provided curve
 * @return the mid point on curve
 */
public static Point2D getMidPoint (CubicCurve2D c)
{
    return new Point2D.Double(
            (c.getX1() + (3 * c.getCtrlX1()) + (3 * c.getCtrlX2()) + c.getX2()) / 8,
            (c.getY1() + (3 * c.getCtrlY1()) + (3 * c.getCtrlY2()) + c.getY2()) / 8);
}