// Copyright 2002, FreeHEP.
package org.freehep.graphicsio.emf.gdi;

import com.google.code.appengine.awt.geom.AffineTransform;
import java.io.IOException;

import org.freehep.graphicsio.emf.EMFConstants;
import org.freehep.graphicsio.emf.EMFInputStream;
import org.freehep.graphicsio.emf.EMFOutputStream;
import org.freehep.graphicsio.emf.EMFTag;
import org.freehep.graphicsio.emf.EMFRenderer;

/**
 * ModifyWorldTransform TAG.
 * 
 * @author Mark Donszelmann
 * @version $Id: ModifyWorldTransform.java 10377 2007-01-23 15:44:34Z duns $
 */
public class ModifyWorldTransform extends EMFTag implements EMFConstants {

    private AffineTransform transform;

    private int mode;

    public ModifyWorldTransform() {
        super(36, 1);
    }

    public ModifyWorldTransform(AffineTransform transform, int mode) {
        this();
        this.transform = transform;
        this.mode = mode;
    }

    public EMFTag read(int tagID, EMFInputStream emf, int len)
            throws IOException {

        return new ModifyWorldTransform(
            emf.readXFORM(),
            emf.readDWORD());
    }

    public void write(int tagID, EMFOutputStream emf) throws IOException {
        emf.writeXFORM(transform);
        emf.writeDWORD(mode);
    }

    public String toString() {
        return super.toString() +
            "\n  transform: " + transform +
            "\n  mode: " + mode;
    }

    /**
     * displays the tag using the renderer
     *
     * @param renderer EMFRenderer storing the drawing session data
     */
    public void render(EMFRenderer renderer) {
        // MWT_IDENTITY 	Resets the current world transformation by using
        // the identity matrix. If this mode is specified, the XFORM structure
        // pointed to by lpXform is ignored.
        if (mode == EMFConstants.MWT_IDENTITY) {
            if (renderer.getPath() != null) {
                renderer.setPathTransform(new AffineTransform());
            } else {
                renderer.resetTransformation();
            }
        }

        // MWT_LEFTMULTIPLY 	Multiplies the current transformation by the
        // data in the XFORM structure. (The data in the XFORM structure becomes
        // the left multiplicand, and the data for the current transformation
        // becomes the right multiplicand.)
        else if (mode == EMFConstants.MWT_LEFTMULTIPLY) {
            if (renderer.getPath() != null) {
                renderer.getPathTransform().concatenate(transform);
                renderer.transform(transform);
            } else {
                renderer.transform(transform);
            }
        }

        // MWT_RIGHTMULTIPLY 	Multiplies the current transformation by the data
        // in the XFORM structure. (The data in the XFORM structure becomes the
        // right multiplicand, and the data for the current transformation
        // becomes the left multiplicand.)
        else if (mode != EMFConstants.MWT_RIGHTMULTIPLY) {
            // TODO expected that this should work but it doesn't
            // doing nothing renders the right emf embedding

            /* if (renderer.getPath() != null) {
                AffineTransform transform = new AffineTransform(this.transform);
                transform.concatenate(renderer.getPathTransform());
                renderer.setPathTransform(transform);
            } else {
                AffineTransform transform = new AffineTransform(this.transform);
                transform.concatenate(renderer.getTransform());
                renderer.resetTransformation();
                renderer.transform(transform);
            }*/
        }

        // Unknown mode
        else {
            logger.warning("unsupport transform mode " + toString());
        }
    }
}