Application: gvSIG desktop

/* gvSIG. Geographic Information System of the Valencian Government

 *

 * Copyright (C) 2007-2008 Infrastructures and Transports Department

 * of the Valencian Government (CIT)

 * 

 * This program is free software; you can redistribute it and/or

 * modify it under the terms of the GNU General Public License

 * as published by the Free Software Foundation; either version 2

 * of the License, or (at your option) any later version.

 * 

 * This program is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 * GNU General Public License for more details.

 * 

 * You should have received a copy of the GNU General Public License

 * along with this program; if not, write to the Free Software

 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, 

 * MA  02110-1301, USA.

 * 

 */

/*

 * AUTHORS (In addition to CIT):

 * 2009 {Iver T.I.}   {Task}

 */

package org.gvsig.fmap.geom.primitive;

/**

 * <p>

 * This interface is equivalent to the GM_Arc specified in 

 * <a href="http://www.iso.org/iso/iso_catalogue/catalogue_tc/catalogue_detail.htm?csnumber=26012">ISO 19107</a>.

 * A Arc is defined by 3 points, and consists of the arc of the circle determined by the 3 points, 

 * starting at the first, passing through the second and terminating at the third. 

 * If the 3 points are co-linear, then the arc shall be a 3-point line string, and will 

 * not be able to return values for center, radius, start angle and end angle. 

 * </p> 

 * @see <a href="http://www.iso.org/iso/iso_catalogue/catalogue_tc/catalogue_detail.htm?csnumber=26012">ISO 19107</a>

 * @author <a href="mailto:jpiera@gvsig.org">Jorge Piera</a>

 */

public interface Arc extends Curve {

        /**

         * Sets the three points to define an arc.

         * These are three ordered points that belong to the arc

         * (none of them is the center of the ellipse/circle). Therefore

         * they must not be aligned.

         * 

         * @param startPoint

         * The start point of an arc.

     * @param midPoint

     * The middle point of an arc.

         * @param endPoint

         * The end point of an arc.

         * @exception IllegalArgumentException if the three points are aligned or

         * there is a repeated point.

         * 

         */

        void setPoints(Point startPoint, Point midPoint, Point endPoint);

        /**

         * Sets the values to define an arc.

         * @param center The center of the arc.

         * @param radius The radius.

         * @param startAngle The start angle of the arc (in radians)

         * @param angleExt The angular extent of the arc (in radians). 

         * 

         * The sign convention is: 

         * 

         * startAngle = 0 is "3 o'clock"; 

         * startAngle = (PI / 3) is "1 o'clock"; 

     * angleExt > 0 means "advancing clockwise"; 

     * angleExt < 0 means "advancing counterclockwise".

         */

        void setPoints (Point center, double radius, double startAngle, double angleExt);

    /**

     * Sets the values to define an arc.

     * @param center The center of the arc.

     * @param radius The radius.

     * @param startAngle The start angle of the arc (in radians)

     * @param angleExt The angular extent of the arc (in radians). 

     * 

     * The sign convention is: 

     * 

     * startAngle = 0 is "3 o'clock"; 

     * startAngle = (PI / 3) is "1 o'clock"; 

     * angleExt > 0 means "advancing clockwise"; 

     * angleExt < 0 means "advancing counterclockwise".

     */

    void setPointsStartExt (Point center, double radius, double startAngle, double angleExt);

    /**

     * Sets the values to define an arc. The arc will go from

     * startAngle to endAngle clockwise. Angles will be

     * normalized to ]-PI, PI] (-PI excluded) before creating

     * the arc. 

     * 

     * @param center The center of the arc.

     * @param radius The radius.

     * @param startAngle The start angle of the arc (in radians)

     * @param endAngle The end angle of the arc (in radians). 

     * 

     */

    void setPointsStartEnd (Point center, double radius, double startAngle, double endAngle );

        /**

         * Return the first point that has been used to create the arc.

         * @return

         * The first point of the arc.

         */

        Point getInitPoint();

        /**

         * Return the end point that has been used to create the arc.

         * @return

         * The end point of the arc.

         */

        Point getEndPoint();

        /**

         * Return the center of the arc, that is, the center of the ellipse/circle

         * in which the arc is based.

         * 

         * @return The center of the arc.

         */

        Point getCenterPoint();

}