/*******************************************************************************
 * 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.geometry.Transform;

import dwt.dwthelper.utils;
import dwtx.draw2d.geometry.Point;

/**
 * Provides support for transformations of scaling, translation and rotation.
 */
public class Transform {

private double
    scaleX = 1.0,
    scaleY = 1.0,
    dx, dy,
    cos = 1.0,
    sin;

/**
 * Sets the value for the amount of scaling to be done along both axes.
 *
 * @param scale  Scale factor
 * @since 2.0
 */
public void setScale(double scale) {
    scaleX = scaleY = scale;
}

/**
 * Sets the value for the amount of scaling to be done along X and Y axes
 * individually.
 *
 * @param x  Amount of scaling on X axis
 * @param y  Amount of scaling on Y axis
 * @since 2.0
 */
public void setScale(double x, double y) {
    scaleX = x;
    scaleY = y;
}

/**
 * Sets the rotation angle.
 *
 * @param angle  Angle of rotation
 * @since 2.0
 */
public void setRotation(double angle) {
    cos = Math.cos(angle);
    sin = Math.sin(angle);
}

/**
 * Sets the translation amounts for both axes.
 *
 * @param x  Amount of shift on X axis
 * @param y  Amount of shift on Y axis
 * @since 2.0
 */
public void setTranslation(double x, double y) {
    dx = x;
    dy = y;
}

/**
 * Returns a new transformed Point of the input Point based on the transformation
 * values set.
 *
 * @param p  Point being transformed
 * @return  The transformed Point
 * @since 2.0
 */
public Point getTransformed(Point p) {
    double x = p.x;
    double y = p.y;
    double temp;
    x *= scaleX;
    y *= scaleY;

    temp = x * cos - y * sin;
    y    = x * sin + y * cos;
    x = temp;
    return new Point(Math.round(x + dx), Math.round(y + dy));
}

}