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/*
 * $Id: JXImagePanel.java 4017 2011-05-10 21:00:48Z kschaefe $
 *
 * Copyright 2004 Sun Microsystems, Inc., 4150 Network Circle,
 * Santa Clara, California 95054, U.S.A. All rights reserved.
 *
 * This library 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 2.1 of the License, or (at your option) any later version.
 *
 * This library 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 library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 */

package org.jdesktop.swingx;

import javax.swing.SwingUtilities;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Image;
import java.awt.Insets;
import java.awt.Rectangle;

/**
 * 
 * A panel that draws an image. The standard mode is to draw the specified image
 * centered and unscaled. The component&s preferred size is based on the
 * image, unless explicitly set by the user.
 * 
 *
 * @author rbair
 */
final class JXImagePanel extends JXPanel {

    /**
     * The image to draw
     */
    private Image img = null;

    /**
     * Sets the image to use for the background of this panel. This image is
     * painted whether the panel is opaque or translucent.
     *
     * @param image if null, clears the image. Otherwise, this will set the
     *              image to be painted. If the preferred size has not been explicitly
     *              set, then the image dimensions will alter the preferred size of
     *              the panel.
     */
    void setImage(Image image) {
        if (image != img) {
            Image oldImage = img;
            img = image;
            firePropertyChange("image", oldImage, img);
            invalidate();
            repaint();
        }
    }

    /**
     * @return the image used for painting the background of this panel
     */
    Image getImage() {
        return img;
    }

    /**
     * {@inheritDoc}
     * The old property value in PCE fired by this method might not be always correct!
     */
    @Override
    public Dimension getPreferredSize() {
        if (!isPreferredSizeSet() && img != null) {
            // it has not been explicitly set, so return the width/height of
            // the image
            int width = img.getWidth(null);
            int height = img.getHeight(null);
            if (width == -1 || height == -1) {
                return super.getPreferredSize();
            }
            Insets insets = getInsets();
            width += insets.left + insets.right;
            height += insets.top + insets.bottom;
            return new Dimension(width, height);
        }
        return super.getPreferredSize();
    }

    /**
     * Overridden to paint the image on the panel
     *
     * @param g
     */
    @Override
    protected void paintComponent(Graphics g) {
        super.paintComponent(g);
        Graphics2D g2 = (Graphics2D) g;
        if (img == null)
            return;
        int imgWidth = img.getWidth(null);
        int imgHeight = img.getHeight(null);
        if (imgWidth == -1 || imgHeight == -1) {
            // image hasn't completed loading, return
            return;
        }

        Insets insets = getInsets();
        int pw = getWidth() - insets.left - insets.right;
        int ph = getHeight() - insets.top - insets.bottom;

        Rectangle clipRect = g2.getClipBounds();
        int imageX = (pw - imgWidth) / 2 + insets.left;
        int imageY = (ph - imgHeight) / 2 + insets.top;
        Rectangle r = SwingUtilities.computeIntersection(imageX, imageY, imgWidth, imgHeight, clipRect);
        if (r.x == 0 && r.y == 0 && (r.width == 0 || r.height == 0))
            return;
        // since I have the intersection, all I need to do is adjust the
        // x & y values for the image
        int txClipX = clipRect.x - imageX;
        int txClipY = clipRect.y - imageY;
        int txClipW = clipRect.width;
        int txClipH = clipRect.height;

        g2.drawImage(
            img, clipRect.x, clipRect.y, clipRect.x + clipRect.width, clipRect.y + clipRect.height,
            txClipX, txClipY, txClipX + txClipW, txClipY + txClipH, null
        );
    }
}