Java 如何调整BuffereImage的大小但保留其图形？

我有自己的自定义控件，用于维护其内容的背景图像。此缓冲区的类型为BuffereImage

注意！背衬图像的使用是出于需求。不要教我在绘画中画画

目前，我正在按以下方式调整图像大小：

@Override
public void setBounds(int x, int y, int width, int height) {

    if( bufferedImage == null ) {
        bufferedImage = new BufferedImage(width, height, BufferedImage.TYPE_INT_ARGB);
    }
    else {
        if( bufferedImage.getWidth() < width || bufferedImage.getHeight() < height ) {
            BufferedImage newImage = new BufferedImage(width, height, BufferedImage.TYPE_INT_ARGB);
            newImage.createGraphics().drawImage(bufferedImage, 0, 0, null);
            bufferedImage = newImage;
        }
    }
    super.setBounds(x, y, width, height);
}

尽管我想覆盖getGraphics

---

是否可以调整图像大小以保留图形对象？

下面是一个小示例，演示如何在Swing中执行自定义绘制：

import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.event.ActionEvent;

import javax.swing.AbstractAction;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;

public class JFrameTest {

    private boolean drawOval = false;

    protected void initUI() {
        final JPanel panel = new JPanel() {
            @Override
            protected void paintComponent(Graphics g) {
                super.paintComponent(g);
                if (drawOval) {
                    g.setColor(Color.BLUE);
                    g.drawOval(0, 0, 100, 100);
                }
            }

            @Override
            public Dimension getPreferredSize() {
                return new Dimension(100, 100);
            }
        };

        AbstractAction drawAction = new AbstractAction("Draw") {

            @Override
            public void actionPerformed(ActionEvent e) {
                drawOval = true;
                panel.repaint();
            }
        };

        JButton drawButton = new JButton(drawAction);

        JPanel buttonPanel = new JPanel();
        buttonPanel.add(drawButton);

        JFrame frame = new JFrame();
        frame.add(panel, BorderLayout.CENTER);
        frame.add(buttonPanel, BorderLayout.SOUTH);

        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.pack();

        frame.setVisible(true);

    }

    public static void main(String[] args) {

        SwingUtilities.invokeLater(new Runnable() {

            @Override
            public void run() {
                new JFrameTest().initUI();
            }
        });

    }
}

---

Swing已经提供了双缓冲，您是否有理由在Swing中维护自己的缓冲区？panel.getGraphics.drawOval0，0，100，100；->永远不要使用getGraphics。相反，替代paintComponent使用该方法的图形参数。无论何时要更新/刷新显示器，请致电repaint@SuzanCioc我绝对没有错。双缓冲意味着您不会看到绘图的每个步骤，相反，您将看到正在绘制的任何内容的即时绘图。无论如何，这是正确的方式来做事情的摇摆。每次请求重新绘制时绘制缓冲图像实际上效率较低，而且主要是useless@SuzanCioc您绝对不是在证明Swing中没有缓冲。@SuzanCioc您这样做的目的是什么？提高绩效？消除视觉故障？我之所以这么问，是因为很可能已经有了内在的方法来做你想做的事情。

import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.event.ActionEvent;

import javax.swing.AbstractAction;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;

public class JFrameTest {

    private boolean drawOval = false;

    protected void initUI() {
        final JPanel panel = new JPanel() {
            @Override
            protected void paintComponent(Graphics g) {
                super.paintComponent(g);
                if (drawOval) {
                    g.setColor(Color.BLUE);
                    g.drawOval(0, 0, 100, 100);
                }
            }

            @Override
            public Dimension getPreferredSize() {
                return new Dimension(100, 100);
            }
        };

        AbstractAction drawAction = new AbstractAction("Draw") {

            @Override
            public void actionPerformed(ActionEvent e) {
                drawOval = true;
                panel.repaint();
            }
        };

        JButton drawButton = new JButton(drawAction);

        JPanel buttonPanel = new JPanel();
        buttonPanel.add(drawButton);

        JFrame frame = new JFrame();
        frame.add(panel, BorderLayout.CENTER);
        frame.add(buttonPanel, BorderLayout.SOUTH);

        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.pack();

        frame.setVisible(true);

    }

    public static void main(String[] args) {

        SwingUtilities.invokeLater(new Runnable() {

            @Override
            public void run() {
                new JFrameTest().initUI();
            }
        });

    }
}