package de.intevation.flys.client.shared;

import java.io.Serializable;


/**
 * This object supports a linear transformation to transform xy coordinates into
 * an other coordinate system based on scale and translation values.
 *
 * @author <a href="mailto:ingo.weinzierl@intevation.de">Ingo Weinzierl</a>
 */
public class Transform2D implements Serializable {

    protected double sx;
    protected double sy;

    protected double tx;
    protected double ty;


    public Transform2D() {
    }


    /**
     * Creates a new transformation with scale and translation factors.
     *
     * @param sx The scale factor for the x axis.
     * @param sy The scale factor for the y axis.
     * @param tx The translation factor for the x axis.
     * @param ty The translation factor for the y axis.
     */
    public Transform2D(double sx, double sy, double tx, double ty) {
        this.sx  = sx;
        this.sy  = sy;
        this.tx  = tx;
        this.ty  = ty;
    }


    /**
     * Transforms the pixel x and y into a new coordinate system based on the
     * scale and translation values specified in the constructor.
     */
    public double[] transform(double x, double y) {
        double resX = sx * x + tx;
        double resY = sy * y + ty;

        return new double[] { resX, resY };
    }
}
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