Calculates center of the arc. - Java java.lang

Java examples for java.lang:Math Geometry

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Description

Calculates center of the arc.

Demo Code

/**/*www  .  ja  v a 2  s . c o m*/
 * Copyright 2012 Petr Mor?vek
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */

public class Main{
    /**
     * Calculates center of the arc.
     *
     * @param point1 first point of the arc
     * @param point2 second point of the arc
     * @param point3 third point of the arc
     *
     * @return center of the arc.
     */
    public static Point getArcCenter(final Point point1,
            final Point point2, final Point point3) {
        final double dx1 = point1.getX() - point2.getX();
        final double dy1 = point1.getY() - point2.getY();
        final double dx3 = point3.getX() - point2.getX();
        final double dy3 = point3.getY() - point2.getY();

        final double ac = dx3 * dy1;
        final double bd = dx1 * dy3;
        if (ac == bd) {
            throw new RuntimeException(
                    "Invalid Circle definition: points are co-linear.");
        }
        final double idet = 0.5 / (ac - bd);

        final double dxs = (dy3 * dy1 * (point3.getY() - point1.getY()) + (dx3
                * ac - dx1 * bd))
                * idet;
        final double dys = (dx3 * dx1 * (point1.getX() - point3.getX()) + (dy1
                * ac - dy3 * bd))
                * idet;
        return new Point(point2.getX() + dxs, point2.getY() + dys);
    }
}

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