imagepanel.java

一款即时通讯软件

package edu.ou.kmi.buddyspace.utils;

/*
 * ImagePanel.java
 *
 * Project: BuddySpace
 * (C) Copyright Knowledge Media Institute 2002
 *
 *
 * Created on 16 August 2002, 17:54
 */

//import java.util.*;
import java.awt.*;
import java.awt.image.*;
import javax.swing.*;

/**
 * <code>Image Panel</code> is a panel displaying given image in given scale.
 *
 * @author  Jiri Komzak, Knowledge Media Institute, Open University, United Kingdom
 */
public class ImagePanel extends JPanel {
    protected Image image;
    protected int width;
    protected int height;
    protected float scale;
    //Container mainPanel;
    protected JComponent mainPanel;

    /** Constructor */
    public ImagePanel(Image image, float scale, JComponent /*Container*/ mainPanel, int imgWidth, int imgHeight) {
        this.image = image;
        this.scale = scale;
        this.mainPanel = mainPanel;
        setScale(scale, imgWidth, imgHeight);
    }
    
    /** Sets scale */
    public void setScale(float scale, int imgWidth, int imgHeight) {
        //width = Math.round(image.getWidth(this) * scale);
        //height = Math.round(image.getHeight(this) * scale);
        width = Math.round(imgWidth * scale);
        height = Math.round(imgHeight * scale);
        setSize(width, height);
    }

    /** Paints the component */
    public void paintComponent(Graphics g) {
        super.paintComponent(g); //paint background

        g.drawImage(image, 0, 0, width, height, this);
    }
    
    /** Called when included image updated */
    public boolean imageUpdate(Image img, int infoflags, int x, int y, int width, int height) {
        if (image == img) {
            if ((infoflags & ImageObserver.WIDTH) != 0) {
                this.width = Math.round(width * scale);
                //this.width = Math.round(image.getWidth(this) * scale);
                //setSize(width, height);
                //maybeResizeParent();
                refresh();
            }
            if ((infoflags & ImageObserver.HEIGHT) != 0) {
                this.height = Math.round(height * scale);
                //this.height = Math.round(image.getHeight(this) * scale);
                //setSize(this.width, this.height);
                //maybeResizeParent();
                refresh();
            }
        }
        
        return super.imageUpdate(img, infoflags, x, y, width, height);
    }
    
    /** When refreshes, refreshes also parent */
    protected void refresh() {
        revalidate();
        repaint();
        mainPanel.revalidate();
        mainPanel.repaint();
    }
    
    /** Changes size of parent if cannot fit in */
    public void maybeResizeParent() {
        int x = getX() + width;
        int y = getY() + height;
        Dimension d = mainPanel.getPreferredSize();
        int px = (int) d.getWidth();
        int py = (int) d.getHeight();
        d = mainPanel.getMinimumSize();
        int mx = (int) d.getWidth();
        int my = (int) d.getHeight();
        
        if (px < x || py < y) {
            px = (x > px)? x : px;
            py = (y > py)? y : py;
            mainPanel.setPreferredSize(new Dimension(px, py));
        }
        if (mx < x || my < y) {
            mx = (x > mx)? x : mx;
            my = (y > my)? y : my;
            mainPanel.setMinimumSize(new Dimension(mx, my));
        }
        
        refresh();
    }
    
}