/*******************************************************************************
 * 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
 * Port to the D programming language:
 *     Frank Benoit <benoit@tionex.de>
 *******************************************************************************/
module dwtx.draw2d.ChopboxAnchor;

import dwt.dwthelper.utils;

import dwtx.draw2d.geometry.Point;
import dwtx.draw2d.geometry.Rectangle;
import dwtx.draw2d.IFigure;
import dwtx.draw2d.AbstractConnectionAnchor;

/**
 * The ChopboxAnchor's location is found by calculating the intersection of a line drawn
 * from the center point of its owner's box to a reference point on that box. Thus
 * {@link Connection Connections} using the ChopBoxAnchor will be oriented such that they
 * point to their owner's center.
 */
public class ChopboxAnchor
    : AbstractConnectionAnchor
{

/**
 * Constructs a new ChopboxAnchor.
 */
protected this() { }

/**
 * Constructs a ChopboxAnchor with the given <i>owner</i> figure.
 *
 * @param owner The owner figure
 * @since 2.0
 */
public this(IFigure owner) {
    super(owner);
}

/**
 * Gets a Rectangle from {@link #getBox()} and returns the Point where a line from the
 * center of the Rectangle to the Point <i>reference</i> intersects the Rectangle.
 *
 * @param reference The reference point
 * @return The anchor location
 */
public Point getLocation(Point reference) {
    Rectangle r = Rectangle.SINGLETON;
    r.setBounds(getBox());
    r.translate(-1, -1);
    r.resize(1, 1);

    getOwner().translateToAbsolute(r);
    float centerX = r.x + 0.5f * r.width;
    float centerY = r.y + 0.5f * r.height;

    if (r.isEmpty() || (reference.x is cast(int)centerX && reference.y is cast(int)centerY))
        return new Point(cast(int)centerX, cast(int)centerY);  //This avoids divide-by-zero

    float dx = reference.x - centerX;
    float dy = reference.y - centerY;

    //r.width, r.height, dx, and dy are guaranteed to be non-zero.
    float scale = 0.5f / Math.max(Math.abs(dx) / r.width, Math.abs(dy) / r.height);

    dx *= scale;
    dy *= scale;
    centerX += dx;
    centerY += dy;

    return new Point(Math.round(centerX), Math.round(centerY));
}

/**
 * Returns the bounds of this ChopboxAnchor's owner.  Subclasses can override this method
 * to adjust the box the anchor can be placed on.  For instance, the owner figure may have
 * a drop shadow that should not be included in the box.
 *
 * @return The bounds of this ChopboxAnchor's owner
 * @since 2.0
 */
protected Rectangle getBox() {
    return getOwner().getBounds();
}

/**
 * Returns the anchor's reference point. In the case of the ChopboxAnchor, this is the
 * center of the anchor's owner.
 *
 * @return The reference point
 */
public Point getReferencePoint() {
    Point ref_ = getBox().getCenter();
    getOwner().translateToAbsolute(ref_);
    return ref_;
}


/**
 * Returns <code>true</code> if the other anchor has the same owner and box.
 * @param obj the other anchor
 * @return <code>true</code> if equal
 */
public override int opEquals(Object obj) {
    if (auto other = cast(ChopboxAnchor)obj ) {
        return other.getOwner() is getOwner() && other.getBox().opEquals(getBox());
    }
    return false;
}

/**
 * The owning figure's hashcode is used since equality is approximately based on the
 * owner.
 * @return the hash code.
 */
public override hash_t toHash() {
    if (getOwner() !is null)
        return (cast(Object)getOwner()).toHash();
    else
        return super.toHash();
}

}