/*******************************************************************************
 * Copyright (c) 2007, 2010 Association for Decentralized Information Management
 * in Industry THTH ry.
 * 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:
 *     VTT Technical Research Centre of Finland - initial API and implementation
 *******************************************************************************/
package org.simantics.graphviz.drawable;

import java.awt.Canvas;
import java.awt.Color;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Point;
import java.awt.RenderingHints;
import java.awt.event.ComponentAdapter;
import java.awt.event.ComponentEvent;
import java.awt.event.KeyAdapter;
import java.awt.event.KeyEvent;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.awt.event.MouseWheelEvent;
import java.awt.event.MouseWheelListener;
import java.awt.geom.AffineTransform;
import java.awt.geom.Rectangle2D;
import java.awt.image.VolatileImage;

/**
 * A canvas showing a given Drawable.
 * 
 * @author Hannu Niemist�
 */
public class ViewerCanvas extends Canvas {

    private static final long serialVersionUID = -1094658958968314511L;
    
    AffineTransform transform;
    Point prev;
    VolatileImage im;
    
    Drawable drawable;

    public ViewerCanvas(Drawable drawable) {
        this.drawable = drawable;
        setBackground(Color.WHITE);    
        addKeyListener(new KeyAdapter() {

            @Override
            public void keyPressed(KeyEvent e) {
                if(e.getKeyChar()=='1') {
                    fit();
                    repaint();
                }
            }

        });
        addMouseListener(new MouseAdapter() {

            @Override
            public void mousePressed(MouseEvent e) {
                prev = e.getPoint();
            }    			
        });
        addMouseMotionListener(new MouseAdapter() {
            @Override
            public void mouseDragged(MouseEvent e) {
                Point cur = e.getPoint();
                double deltaX = cur.getX()-prev.getX();
                double deltaY = cur.getY()-prev.getY();					
                transform.preConcatenate(AffineTransform.getTranslateInstance(deltaX, deltaY));						
                repaint();
                prev = cur;
            }
        });
        addMouseWheelListener(new MouseWheelListener() {

            @Override
            public void mouseWheelMoved(MouseWheelEvent e) {
                if(transform != null) {
                    double scale = Math.exp(-0.1*e.getUnitsToScroll());
                    Point p = e.getPoint();
                    AffineTransform mod = new AffineTransform();
                    mod.translate(p.getX(), p.getY());
                    mod.scale(scale, scale);
                    mod.translate(-p.getX(), -p.getY());
                    transform.preConcatenate(mod);						
                    repaint();
                }
            }

        });
        addComponentListener(new ComponentAdapter() {
            @Override
            public void componentResized(ComponentEvent e) {
            	if(getWidth() > 0 && getHeight() > 0) {
            		im = createVolatileImage(getWidth(), getHeight());
            		repaint();
            	}
            }
        });
    }

    public void fit() {
        Rectangle2D bounds = drawable.getBounds();

        Rectangle2D container = getBounds();
        double scale = Math.min(
            container.getWidth() / bounds.getWidth(), 
            container.getHeight() / bounds.getHeight());

        transform = new AffineTransform(
            scale, 0.0,
            0.0, scale,
            container.getX() + container.getWidth() * 0.5 - bounds.getCenterX() * scale,
            container.getY() + container.getHeight() * 0.5 - bounds.getCenterY() * scale
        );
    }

    @Override
    public void paint(Graphics _g) {
    	do {
    		if (im == null || im.validate(getGraphicsConfiguration()) ==
    			VolatileImage.IMAGE_INCOMPATIBLE) {
    		    im = createVolatileImage(getWidth(), getHeight());
    		}
    		
	        Graphics2D g = (Graphics2D)im.getGraphics();
	        
	        g.clearRect(0, 0, im.getWidth(null), im.getHeight(null));
	
	        g.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
	        g.setRenderingHint(RenderingHints.KEY_RENDERING, RenderingHints.VALUE_RENDER_QUALITY);
	        g.setRenderingHint(RenderingHints.KEY_TEXT_ANTIALIASING, RenderingHints.VALUE_TEXT_ANTIALIAS_ON);
	
	        if(transform == null)
	            fit();
	        g.setTransform(transform);
	
	        drawable.draw(g, null);
            g.dispose();
    	} while(im.contentsLost());

        _g.drawImage(im, 0, 0, this);
    }

    @Override
    public void update(Graphics g) {
        paint(g);
    }
    
    public AffineTransform getTransform() {
    	return transform;
    }

}