/*******************************************************************************
 * Copyright (c) 2000, 2005 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *     Alex Selkov - Fix for Bug# 22701
 * Port to the D programming language:
 *     Frank Benoit <benoit@tionex.de>
 *******************************************************************************/
module dwtx.draw2d.Polygon;

import dwt.dwthelper.utils;
import dwtx.dwtxhelper.Collection;
import dwtx.draw2d.Polyline;
import dwtx.draw2d.Graphics;
import dwtx.draw2d.IFigure;

/**
 * Renders a {@link dwtx.draw2d.geometry.PointList} as a polygonal shape.
 * This class is similar to Polyline, except the PointList is closed and can be filled in
 * as a solid shape.
 * @see Polyline
 */
public class Polygon
    : Polyline
{

/**
 * Returns whether the point (x,y) is contained inside this polygon.
 * @param x the X coordinate
 * @param y the Y coordinate
 * @return whether the point (x,y) is contained in this polygon
 */
public bool containsPoint(int x, int y) {
    if (!getBounds().contains(x, y))
        return false;

    bool isOdd = false;
    int[] pointsxy = getPoints().toIntArray();
    int n = pointsxy.length;
    if (n > 3) { //If there are at least 2 Points (4 ints)
        int x1, y1;
        int x0 = pointsxy[n - 2];
        int y0 = pointsxy[n - 1];

        for (int i = 0; i < n; x0 = x1, y0 = y1) {
            x1 = pointsxy[i++];
            y1 = pointsxy[i++];

            if (y0 <= y && y < y1
              && crossProduct(x1, y1, x0, y0, x, y) > 0)
                isOdd = !isOdd;
            if (y1 <= y && y < y0
              && crossProduct(x0, y0, x1, y1, x, y) > 0)
                isOdd = !isOdd;
        }
        if (isOdd)
            return true;
    }

    List children = getChildren();
    for (int i = 0; i < children.size(); i++)
        if ((cast(IFigure) children.get(i)).containsPoint(x, y))
            return true;

    return false;
}

private int crossProduct(int ax, int ay, int bx, int by, int cx, int cy) {
    return (ax - cx) * (by - cy) - (ay - cy) * (bx - cx);
}

/**
 * Fill the Polygon with the background color set by <i>g</i>.
 *
 * @param g the Graphics object
 * @since 2.0
 */
protected void fillShape(Graphics g) {
    g.fillPolygon(getPoints());
}

/**
 * Draw the outline of the Polygon.
 *
 * @param g the Graphics object
 * @since 2.0
 */
protected void outlineShape(Graphics g) {
    g.drawPolygon(getPoints());
}

}