/*
 *  eXist Image Module Extension
 *  Copyright (C) 2006-09 Adam Retter <adam.retter@exist-db.org>
 *  www.adamretter.co.uk
 *  
 *  This program is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU Lesser General Public License
 *  as published by the Free Software Foundation; either version 2
 *  of the License, or (at your option) any later version.
 *  
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU Lesser General Public License for more details.
 *  
 *  You should have received a copy of the GNU Lesser General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 *  
 *  $Id$
 */
package org.exist.xquery.modules.image;

import java.awt.Graphics2D;
import java.awt.Image;
import java.awt.RenderingHints;
import java.awt.image.BufferedImage;
import java.util.List;
import java.util.Map;

import org.exist.xquery.AbstractInternalModule;
import org.exist.xquery.FunctionDef;


/**
 * eXist Image Module Extension
 * 
 * An extension module for the eXist Native XML Database that allows operations
 * on images stored in the eXist database.
 * 
 * @author Adam Retter <adam@exist-db.org>
 * @author ljo
 * @serial 2006-03-10
 * @version 1.0
 *
 * @see org.exist.xquery.AbstractInternalModule#AbstractInternalModule(org.exist.xquery.FunctionDef[], java.util.Map) 
 */
public class ImageModule extends AbstractInternalModule {

    public final static String NAMESPACE_URI = "http://exist-db.org/xquery/image";
	
    public final static String PREFIX = "image";
    public final static String INCLUSION_DATE = "2006-03-13";
    public final static String RELEASED_IN_VERSION = "eXist-1.2";

    private final static FunctionDef[] functions = {
        new FunctionDef(GetWidthFunction.signature, GetWidthFunction.class),
        new FunctionDef(GetHeightFunction.signature, GetHeightFunction.class),
        new FunctionDef(GetMetadataFunction.signatures[0], GetMetadataFunction.class),
        new FunctionDef(ScaleFunction.signature, ScaleFunction.class),
        new FunctionDef(GetThumbnailsFunction.signature, GetThumbnailsFunction.class),
        new FunctionDef(CropFunction.signature, CropFunction.class)
    };
	
    public ImageModule(Map<String, List<? extends Object>> parameters) {
        super(functions, parameters);
    }

    @Override
    public String getNamespaceURI() {
        return NAMESPACE_URI;
    }

    @Override
    public String getDefaultPrefix() {
        return PREFIX;
    }

    @Override
    public String getDescription() {
        return "A module for performing operations on Images stored in the eXist db";
    }

    @Override
    public String getReleaseVersion() {
        return RELEASED_IN_VERSION;
    }
	
    /**
     * @author Rafael Troilo <rtroilo@gmail.com>
     */
    protected static BufferedImage createThumb(Image image, int height, int width) {
        int thumbWidth = 0;
        int thumbHeight = 0;
        double scaleFactor = 0.0;
        BufferedImage thumbImage = null;
        Graphics2D graphics2D = null;

        int imageHeight = image.getHeight(null);
        int imageWidth = image.getWidth(null);

        if(imageHeight >= imageWidth) {
            scaleFactor = (double)height / (double)imageHeight;
            thumbWidth = (int)(imageWidth * scaleFactor);
            thumbHeight = height;
            if(thumbWidth > width) { // thumbwidth is greater than
                // maxThumbWidth, so we have to scale
                // again
                scaleFactor = (double)width / (double)thumbWidth;
                thumbHeight = (int)(thumbHeight * scaleFactor);
                thumbWidth = width;
            }
        } else {
            scaleFactor = (double)width / (double)imageWidth;
            thumbHeight = (int)(imageHeight * scaleFactor);
            thumbWidth = width;
            if(thumbHeight > height) { // thumbHeight is greater than
                // maxThumbHeight, so we have to scale
                // again
                scaleFactor = (double)height / (double)thumbHeight;
                thumbWidth = (int)(thumbWidth * scaleFactor);
                thumbHeight = height;
            }
        }

        thumbImage = new BufferedImage(thumbWidth, thumbHeight, BufferedImage.TYPE_INT_RGB);
        graphics2D = thumbImage.createGraphics();
        graphics2D.setRenderingHint(RenderingHints.KEY_INTERPOLATION, RenderingHints.VALUE_INTERPOLATION_BILINEAR);
        graphics2D.drawImage(image, 0, 0, thumbWidth, thumbHeight, null);
        graphics2D.dispose();
        
        return thumbImage;
    }
}