如何实现图形的放大功能？

[carlosfu1]

代码框架我已经写好了，麻烦高手帮忙。

import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.geom.*;
import javax.swing.*;

public class DrawTest
{
   public static void main(String[] args)
   {
      EventQueue.invokeLater(new Runnable()
         {
            public void run()
            {
               DrawFrame frame = new DrawFrame();
               frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
               frame.setVisible(true);
            }
         });
   }
}
class DrawFrame extends JFrame
{
   private JButton btn1,btn2;
   private DrawComponent component;
   
   public DrawFrame()
   {
      setTitle("DrawTest");
      setSize(400,400);
      
      btn1=new JButton("放大");
      btn2=new JButton("缩小");
      
      btn1.addActionListener(new ButtonActionListener());
      
      Panel controlPanel=new Panel();
      controlPanel.add(btn1);
      controlPanel.add(btn2);
      
      component = new DrawComponent();
      
      add(controlPanel,BorderLayout.NORTH);
      add(component,BorderLayout.CENTER);
   }
   class ButtonActionListener implements ActionListener{
    public void actionPerformed(ActionEvent e) {
        // TODO Auto-generated method stub
        JButton button = (JButton)e.getSource();
        if(button==btn1){    
            
        }
    }
   }
}
class DrawComponent extends JComponent
{
public void paintComponent(Graphics g)
   {
      Graphics2D g2 = (Graphics2D) g;
      Rectangle2D rect = new Rectangle2D.Double(100,100,200,200);
      g2.draw(rect);
   }
}

[crazylaa]

jf

[pjw100]

放大的话，原图应该是张大图。
初始显示的时候创建Image可以设置size.
方法的话，根据你的倍率来，提供多大的倍率，就放大多少倍，都以原图为基础，因为原图是最大的。
比如当前图片为50*50，原图为1000*1000（这缩小了20倍）。如果要放大一倍，就是100*100.那么就在原图的基础上缩小10倍。

[amdgaming]

贴一个 别人写的 我改改的，，，很多地方不规范 还有多于的东西 你自己 改吧

package com.element.swing;

import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.GridLayout;
import java.awt.Image;
import java.awt.Toolkit;
import java.awt.color.ColorSpace;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.image.BufferedImage;
import java.awt.image.ColorConvertOp;
import java.awt.image.CropImageFilter;
import java.awt.image.FilteredImageSource;
import java.awt.image.ImageFilter;
import java.io.File;
import java.io.IOException;

import javax.imageio.ImageIO;
import javax.swing.ImageIcon;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
import javax.swing.UIManager;

public class ChangeImageSize extends JPanel {

	static Image image1 = null;

	static int i = 1;
	JLabel label3;

	public ChangeImageSize() {
		super(new GridLayout(3, 1)); // 3 rows, 1 column

		label3 = new JLabel(new ImageIcon("c:/google1.png"));
		add(label3);
		JButton setBigButton = new JButton("放大");
		add(setBigButton);
		setBigButton.addActionListener(new ActionListener() {

			@Override
			public void actionPerformed(ActionEvent e) {

				setBigButton();
			}
		});
	}

	protected void setBigButton() {
		Image temp = scale("c:/google1.png", "C:/image.png", i++, true);
		label3.setIcon(new ImageIcon(temp));
	}

	/**
	 * Create the GUI and show it. For thread safety, this method should be
	 * invoked from the event dispatch thread.
	 */
	private static void createAndShowGUI() {
		// Create and set up the window.
		JFrame frame = new JFrame("LabelDemo");
		frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

		// Add content to the window.
		frame.add(new ChangeImageSize());
		frame.setPreferredSize(new Dimension(800, 600));

		// Display the window.
		frame.pack();
		frame.setVisible(true);
	}

	public static void main(String[] args) {
		// Schedule a job for the event dispatch thread:
		// creating and showing this application's GUI.

		SwingUtilities.invokeLater(new Runnable() {
			public void run() {
				// Turn off metal's use of bold fonts
				UIManager.put("swing.boldMetal", Boolean.FALSE);

				createAndShowGUI();
			}
		});

	}

	/** */
	/**
	 * 缩放图像
	 * 
	 * @param srcImageFile
	 *            源图像文件地址
	 * @param result
	 *            缩放后的图像地址
	 * @param scale
	 *            缩放比例
	 * @param flag
	 *            缩放选择:true 放大; false 缩小;
	 */
	public static Image scale(String srcImageFile, String result, double scale,
			boolean flag) {
		try {
			BufferedImage src = ImageIO.read(new File(srcImageFile)); // 读入文件
			int width = src.getWidth(); // 得到源图宽
			int height = src.getHeight(); // 得到源图长
			if (flag) {
				// 放大
				width = (int) (width * scale);
				height = (int) (height * scale);
			} else {
				// 缩小
				width = (int) (width / scale);
				height = (int) (height / scale);
			}
			Image image = src.getScaledInstance(width, height,
					Image.SCALE_SMOOTH);
			// BufferedImage tag = new BufferedImage(width, height,
			// BufferedImage.TYPE_INT_RGB);
			// Graphics g = tag.getGraphics();
			// g.drawImage(image, 0, 0, null); // 绘制缩小后的图
			// g.dispose();
			image1 = image;

			// ImageIO.write(tag, "JPEG", new File(result));// 输出到文件流
		} catch (IOException e) {
			e.printStackTrace();
		}
		return image1;
	}

	/** */
	/**
	 * 图像切割
	 * 
	 * @param srcImageFile
	 *            源图像地址
	 * @param descDir
	 *            切片目标文件夹
	 * @param destWidth
	 *            目标切片宽度
	 * @param destHeight
	 *            目标切片高度
	 */
	public static void cut(String srcImageFile, String descDir, int destWidth,
			int destHeight) {
		try {
			Image img;
			ImageFilter cropFilter;
			// 读取源图像
			BufferedImage bi = ImageIO.read(new File(srcImageFile));
			int srcWidth = bi.getHeight(); // 源图宽度
			int srcHeight = bi.getWidth(); // 源图高度
			if (srcWidth > destWidth && srcHeight > destHeight) {
				Image image = bi.getScaledInstance(srcWidth, srcHeight,
						Image.SCALE_DEFAULT);
				destWidth = 200; // 切片宽度
				destHeight = 150; // 切片高度
				int cols = 0; // 切片横向数量
				int rows = 0; // 切片纵向数量
				// 计算切片的横向和纵向数量
				if (srcWidth % destWidth == 0) {
					cols = srcWidth / destWidth;
				} else {
					cols = (int) Math.floor(srcWidth / destWidth) + 1;
				}
				if (srcHeight % destHeight == 0) {
					rows = srcHeight / destHeight;
				} else {
					rows = (int) Math.floor(srcHeight / destHeight) + 1;
				}
				// 循环建立切片
				// 改进的想法:是否可用多线程加快切割速度
				for (int i = 0; i < rows; i++) {
					for (int j = 0; j < cols; j++) {
						// 四个参数分别为图像起点坐标和宽高
						// 即: CropImageFilter(int x,int y,int width,int height)
						cropFilter = new CropImageFilter(j * 200, i * 150,
								destWidth, destHeight);
						img = Toolkit.getDefaultToolkit().createImage(
								new FilteredImageSource(image.getSource(),
										cropFilter));
						BufferedImage tag = new BufferedImage(destWidth,
								destHeight, BufferedImage.TYPE_INT_RGB);
						Graphics g = tag.getGraphics();
						g.drawImage(img, 0, 0, null); // 绘制缩小后的图
						g.dispose();
						// 输出为文件
						ImageIO.write(tag, "JPEG", new File(descDir
								+ "pre_map_" + i + "_" + j + ".jpg"));
					}
				}
			}
		} catch (Exception e) {
			e.printStackTrace();
		}
	}

	/** */
	/**
	 * 图像类型转换 GIF->JPG GIF->PNG PNG->JPG PNG->GIF(X)
	 */
	public static void convert(String source, String result) {
		try {
			File f = new File(source);
			f.canRead();
			f.canWrite();
			BufferedImage src = ImageIO.read(f);
			ImageIO.write(src, "JPG", new File(result));
		} catch (Exception e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
	}

	/** */
	/**
	 * 彩色转为黑白
	 * 
	 * @param source
	 * @param result
	 */
	public static void gray(String source, String result) {
		try {
			BufferedImage src = ImageIO.read(new File(source));
			ColorSpace cs = ColorSpace.getInstance(ColorSpace.CS_GRAY);
			ColorConvertOp op = new ColorConvertOp(cs, null);
			src = op.filter(src, null);
			ImageIO.write(src, "JPEG", new File(result));
		} catch (IOException e) {
			e.printStackTrace();
		}
	}

}

[wxzyydy]

帮忙顶顶，顺便接点分，谢谢

[nj_dobetter]

矢量图，就只能修改图形坐标重画了。

[老张-AI]

3楼代码给了
up

[xijiro]

图像放大后 不失真怎样实现？？