| gvSIG desktop 1

import java.awt.geom.Rectangle2D;

		// =================================

		double deg_rad = Math.PI / 180.0;

		Point cp = (Point)manager.create(TYPES.POINT, SUBTYPES.GEOM2D);

        cp.setX(10);

        cp.setY(2);

		arc.setPointsStartExt(cp, 5, 45*deg_rad, 135*deg_rad);

        assertEquals(10, arc.getEndPoint().getX(), 0.000001);

        assertEquals(-3, arc.getEndPoint().getY(), 0.000001);

        Rectangle2D rect = new Rectangle2D.Double(0, 0, 9, 9);

        arc.setPointsStartEnd(cp, 5, 45*deg_rad, -90*deg_rad);

        assertFalse(arc.intersects(rect));

        arc.setPointsStartEnd(cp, 5, 45*deg_rad, 5d*Math.PI/2d);

        assertTrue(arc.intersects(rect));

    /**

     * 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 );

    /* (non-Javadoc)

     * @see org.gvsig.fmap.geom.primitive.Arc#setPointsStartExt(org.gvsig.fmap.geom.primitive.Point, double, double, double)

     */

    public void setPointsStartExt(Point center, double radius,

        double startAngle, double angleExt) {

        setPoints(center, radius, startAngle, angleExt);

    }

    /* (non-Javadoc)

     * @see org.gvsig.fmap.geom.primitive.Arc#setPointsStartEnd(org.gvsig.fmap.geom.primitive.Point, double, double, double)

     */

    public void setPointsStartEnd(Point center, double radius,

        double startAngle, double endAngle) {

        if (startAngle == endAngle) {

            setPointsStartExt(center, radius, startAngle, 0);

        } else {

            /*

             * Normalize then force clockwise:

             */

            double norm_start = normalizeAngle(startAngle);

            double norm_end = normalizeAngle(endAngle);

            double ang_ext = 0;

            // clockwise

            // ang_ext must be positive

            if (norm_start >= norm_end) {

                ang_ext = norm_start - norm_end;

            } else {

                ang_ext = 2 * Math.PI - (norm_end - norm_start);

            }

            // finally call other method with ang_ext

            setPointsStartExt(center, radius, startAngle, ang_ext);

        }

    }

	/**

	 * Leaves the angle between PI and -PI

     * @param angle (radians)

     * @return

     */

    private double normalizeAngle(double angle) {

        if (angle > -Math.PI && angle <= Math.PI) {

            return angle;

        }

        if (angle == Double.NEGATIVE_INFINITY

            || angle == Double.POSITIVE_INFINITY) {

            return 0;

        }

        double abs_ang = Math.abs(angle);

        double remove = Math.floor(abs_ang / (2 * Math.PI));

        remove = remove * 2 * Math.PI;

        double resp = 0;

        if (angle > 0) {

            resp = angle - remove;

            if (resp > Math.PI) {

                // final adjustment

                resp = resp - 2 * Math.PI;

            }

        } else {

            resp = angle + remove;

            if (resp <= -Math.PI) {

                // final adjustment

                resp = resp + 2 * Math.PI;

            }

        }

        return resp;

    }

    /* (non-Javadoc)