/**
 * Copyright (C) 2001-2017 by RapidMiner and the contributors
 * 
 * Complete list of developers available at our web site:
 * 
 * http://rapidminer.com
 * 
 * This program is free software: you can redistribute it and/or modify it under the terms of the
 * GNU Affero General Public License as published by the Free Software Foundation, either version 3
 * 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
 * Affero General Public License for more details.
 * 
 * You should have received a copy of the GNU Affero General Public License along with this program.
 * If not, see http://www.gnu.org/licenses/.
*/
package com.rapidminer.gui.tools;

import java.awt.Component;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Image;
import java.awt.RenderingHints;
import java.awt.image.ImageObserver;
import java.net.URL;

import javax.swing.GrayFilter;
import javax.swing.ImageIcon;


/**
 * An {@link ImageIcon} that scales the loaded image without modifying the image buffer itself. For
 * instance, a {@link ScaledImageIcon} with an image of size 96x96 and a scaling factor of 4 would
 * be displayed as 24x24 icon. This is useful in environment where the physical resolution of the
 * screen is higher than the logical (e.g., on Apple Retina displays).
 *
 * @author Michael Knopf, Marcel Seifert
 */
public class ScaledImageIcon extends ImageIcon {

	private static final long serialVersionUID = 1L;

	/** The scaling factor. */
	private int height;
	private int width;

	/**
	 * Creates a new scaled {@link ImageIcon} from the given URL with the given logical height and
	 * width.
	 *
	 * @param url
	 *            the image URL
	 * @param scalingFactor
	 *            the scaling factor
	 */
	public ScaledImageIcon(URL url, int heigth, int width) {
		super(url);
		if (heigth < 1) {
			throw new IllegalArgumentException("Heigth must be positive and non-zero!");
		}
		if (width < 1) {
			throw new IllegalArgumentException("Width must be positive and non-zero!");
		}
		this.height = heigth;
		this.width = width;
	}

	/**
	 * Creates a new scaled {@link ImageIcon} based on the given Image with the given logical height
	 * and width.
	 *
	 * @param image
	 *            the base image
	 * @param scalingFactor
	 *            the scaling factor
	 */
	public ScaledImageIcon(Image image, int heigth, int width) {
		super(image);
		if (heigth < 1) {
			throw new IllegalArgumentException("Heigth must be positive and non-zero!");
		}
		if (width < 1) {
			throw new IllegalArgumentException("Width must be positive and non-zero!");
		}
		this.height = heigth;
		this.width = width;
	}

	@Override
	public int getIconHeight() {
		return this.height;
	}

	@Override
	public int getIconWidth() {
		return this.width;
	}

	@Override
	public synchronized void paintIcon(Component c, Graphics graphics, int x, int y) {
		Image image = super.getImage();
		ImageObserver observer = getImageObserver();
		if (observer == null) {
			observer = c;
		}

		Graphics2D g = (Graphics2D) graphics.create();
		g.setRenderingHint(RenderingHints.KEY_INTERPOLATION, RenderingHints.VALUE_INTERPOLATION_BILINEAR);
		g.drawImage(image, x, y, getIconWidth(), getIconHeight(), observer);
		g.dispose();
	}

	/**
	 * Returns this icon's <code>Image</code> scaled down to its logical size for compatibility
	 * reasons.
	 *
	 * @return the <code>Image</code> object for this <code>ImageIcon</code>
	 */
	@Override
	public Image getImage() {
		return super.getImage().getScaledInstance(getIconWidth(), getIconHeight(), Image.SCALE_SMOOTH);
	}

	/**
	 * Creates a grayed out version of this icon.
	 *
	 * @return the disabled icon
	 */
	public ScaledImageIcon createDisabledIcon() {
		Image grayImage = GrayFilter.createDisabledImage(super.getImage());
		return new ScaledImageIcon(grayImage, height, width);
	}

}