java - Swing 上光滑的圆角

我想为我的秋千应用制作光滑的圆角，但是我无法获得想要的结果...

这是屏幕截图:

1. JFrame的setShape():

2.为JPanel覆盖paintComponent()方法，而不是使用setShape():

3. JFrame的setBackground(new Color(0, 0, 0, 0)):

很好，但是文本质量存在问题:

在第3步之前:

步骤3之后:

伙计们，我很困惑，我搜索了很多次，但没有任何帮助...
我应该怎么办？请帮我

这是完整的代码:

public class WelcomePage extends JFrame {

private Point initialClick;
private boolean end = false;
private JLabel jLabelAppTitle;
private JPanel jPanelExit;
private JLabel jLabelHint;
private int r = 220, g = 0, b = 0;
private int r2 = 10, g2 = 10, b2 = 10;
private boolean flag = false;

public WelcomePage() {
    initComponents();
//    setShape(new RoundRectangle2D.Double(0, 0, getWidth(), getHeight(), 15, 15));
    centerLocation();
    refreshPage();
}

public static void main(String args[]) {
    try {
        for (UIManager.LookAndFeelInfo info : UIManager.getInstalledLookAndFeels()) {
            if ("Nimbus".equals(info.getName())) {
                UIManager.setLookAndFeel(info.getClassName());
                break;
            }
        }
    } catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException e) {
        e.printStackTrace();
    }
    EventQueue.invokeLater(() -> FadeTransitions.fadeIn(new WelcomePage(), FadeTransitions.NORMAL_FADE, true));
}

private void refreshPage() {
    Timer timer = new Timer(20, e -> {
        if (!end) {
            if (r == 220 && b == 0 && g < 220) {
                g++;
            } else if (g == 220 && b == 0 && r > 0) {
                r--;
            } else if (g == 220 && r == 0 && b < 220) {
                b++;
            } else if (b == 220 && r == 0 && g > 0) {
                g--;
            } else if (b == 220 && g == 0 && r < 220) {
                r++;
            } else if (r == 220 && g == 0 && b > 0) {
                b--;
            }
            if (!flag) {
                r2 += 5;
                g2 += 5;
                b2 += 5;
                if (r2 == 250) {
                    flag = true;
                }
            } else {
                r2 -= 5;
                g2 -= 5;
                b2 -= 5;
                if (r2 == 10) {
                    flag = false;
                }
            }
            jLabelAppTitle.setForeground(new Color(r, g, b));
            jLabelHint.setForeground(new Color(r2, g2, b2));
        } else {
            ((Timer) e.getSource()).stop();
        }
    });
    timer.setCoalesce(true);
    timer.setRepeats(true);
    timer.start();
}

private void centerLocation() throws HeadlessException {
    final Toolkit toolkit = Toolkit.getDefaultToolkit();
    final Dimension screenSize = toolkit.getScreenSize();
    final int x = (screenSize.width - this.getWidth()) / 2;
    final int y = (screenSize.height - this.getHeight()) / 2;
    this.setLocation(x, y);
}

@SuppressWarnings("unchecked")
private void initComponents() {

    JPanel jPanelMain = new JPanel() {
        @Override
        protected void paintComponent(Graphics g) {
            Graphics2D g2 = (Graphics2D) g.create();
            RenderingHints qualityHints = new RenderingHints(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
            qualityHints.put(RenderingHints.KEY_RENDERING, RenderingHints.VALUE_RENDER_QUALITY);
            g2.setRenderingHints(qualityHints);
            g2.setPaint(Color.WHITE);
            g2.fillRoundRect(0, 0, getWidth(), getHeight(), 25, 25);
            g2.dispose();
        }
    };
    jPanelExit = new JPanel();
    JLabel jLabelExit = new JLabel();
    JLabel jLabelWelcome = new JLabel();
    jLabelAppTitle = new JLabel();
    jLabelHint = new JLabel();
    JButton jButtonGo = new JButton();
    setDefaultCloseOperation(WindowConstants.DO_NOTHING_ON_CLOSE);
    setTitle("welcome to My App!");
    setUndecorated(true);
    setBackground(new Color(0, 0, 0, 0));

    addWindowListener(new WindowAdapter() {
        @Override
        public void windowClosing(WindowEvent e) {
            close();
        }
    });
    addMouseMotionListener(new java.awt.event.MouseMotionAdapter() {
        public void mouseDragged(MouseEvent evt) {
            thisMouseDragged(evt);
        }
    });
    addMouseListener(new java.awt.event.MouseAdapter() {
        public void mousePressed(MouseEvent evt) {
            thisMousePressed(evt);
        }
    });

    jPanelMain.setBackground(Color.WHITE);
    jPanelExit.setBackground(new Color(160, 0, 20));

    jLabelExit.setFont(new Font("Tahoma", Font.BOLD, 13));
    jLabelExit.setForeground(new Color(255, 255, 255));
    jLabelExit.setHorizontalAlignment(SwingConstants.CENTER);
    jLabelExit.setText("X");
    jLabelExit.setCursor(new Cursor(Cursor.HAND_CURSOR));
    jLabelExit.addMouseListener(new java.awt.event.MouseAdapter() {
        public void mouseClicked(MouseEvent evt) {
            jLabelExitMouseClicked();
        }

        public void mouseEntered(MouseEvent evt) {
            jLabelExitMouseEntered();
        }

        public void mouseExited(MouseEvent evt) {
            jLabelExitMouseExited();
        }
    });

    GroupLayout jPanelExitLayout = new GroupLayout(jPanelExit);
    jPanelExit.setLayout(jPanelExitLayout);
    jPanelExitLayout.setHorizontalGroup(
            jPanelExitLayout.createParallelGroup(GroupLayout.Alignment.LEADING)
                    .addGroup(GroupLayout.Alignment.TRAILING, jPanelExitLayout.createSequentialGroup()
                            .addGap(0, 0, Short.MAX_VALUE)
                            .addComponent(jLabelExit, GroupLayout.PREFERRED_SIZE, 45, GroupLayout.PREFERRED_SIZE))
    );
    jPanelExitLayout.setVerticalGroup(
            jPanelExitLayout.createParallelGroup(GroupLayout.Alignment.LEADING)
                    .addGroup(GroupLayout.Alignment.TRAILING, jPanelExitLayout.createSequentialGroup()
                            .addGap(0, 0, Short.MAX_VALUE)
                            .addComponent(jLabelExit, GroupLayout.PREFERRED_SIZE, 22, GroupLayout.PREFERRED_SIZE))
    );

    jLabelWelcome.setFont(new Font("Tahoma", 0, 25));
    jLabelWelcome.setForeground(new Color(0, 0, 100));
    jLabelWelcome.setHorizontalAlignment(SwingConstants.CENTER);
    jLabelWelcome.setText("Welcome");

    jLabelAppTitle.setFont(new Font("MV Boli", 0, 29));
    jLabelAppTitle.setHorizontalAlignment(SwingConstants.CENTER);
    jLabelAppTitle.setText("My Swing App");

    jButtonGo.setBackground(new Color(100, 20, 80));
    jButtonGo.setFont(new Font("Tahoma", 0, 15));
    jButtonGo.setForeground(new Color(255, 255, 255));
    jButtonGo.setText("GO");
    jButtonGo.addActionListener(evt -> jButtonGoActionPerformed());

    jLabelHint.setFont(new Font("Tahoma", 0, 11));
    jLabelHint.setHorizontalAlignment(SwingConstants.CENTER);
    jLabelHint.setText("press GO button");

    javax.swing.GroupLayout jPanelMainLayout = new javax.swing.GroupLayout(jPanelMain);
    jPanelMain.setLayout(jPanelMainLayout);
    jPanelMainLayout.setHorizontalGroup(
            jPanelMainLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                    .addGroup(jPanelMainLayout.createSequentialGroup()
                            .addContainerGap(48, Short.MAX_VALUE)
                            .addGroup(jPanelMainLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                                    .addGroup(javax.swing.GroupLayout.Alignment.TRAILING, jPanelMainLayout.createSequentialGroup()
                                            .addGap(0, 0, Short.MAX_VALUE)
                                            .addComponent(jPanelExit, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
                                            .addGap(15, 15, 15))
                                    .addGroup(jPanelMainLayout.createSequentialGroup()
                                            .addGroup(jPanelMainLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.TRAILING, false)
                                                    .addComponent(jLabelWelcome, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
                                                    .addComponent(jLabelAppTitle, javax.swing.GroupLayout.DEFAULT_SIZE, 220, Short.MAX_VALUE)
                                                    .addComponent(jLabelHint, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
                                                    .addComponent(jButtonGo, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE))
                                            .addContainerGap(48, Short.MAX_VALUE))))
    );
    jPanelMainLayout.setVerticalGroup(
            jPanelMainLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                    .addGroup(jPanelMainLayout.createSequentialGroup()
                            .addComponent(jPanelExit, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
                            .addGap(64, 64, 64)
                            .addComponent(jLabelWelcome, javax.swing.GroupLayout.PREFERRED_SIZE, 28, javax.swing.GroupLayout.PREFERRED_SIZE)
                            .addGap(98, 98, 98)
                            .addComponent(jLabelAppTitle)
                            .addGap(86, 86, 86)
                            .addComponent(jLabelHint)
                            .addGap(24, 24, 24)
                            .addComponent(jButtonGo, javax.swing.GroupLayout.PREFERRED_SIZE, 40, javax.swing.GroupLayout.PREFERRED_SIZE)
                            .addGap(86, 86, 86))
    );

    javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
    getContentPane().setLayout(layout);
    layout.setHorizontalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                    .addGroup(layout.createSequentialGroup()
                            .addGap(0, 0, 0)
                            .addComponent(jPanelMain, javax.swing.GroupLayout.DEFAULT_SIZE, 316, Short.MAX_VALUE)
                            .addGap(0, 0, 0))
    );
    layout.setVerticalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                    .addGroup(layout.createSequentialGroup()
                            .addGap(0, 0, 0)
                            .addComponent(jPanelMain, javax.swing.GroupLayout.DEFAULT_SIZE, 473, Short.MAX_VALUE)
                            .addGap(0, 0, 0))
    );

    pack();
}

private void thisMousePressed(MouseEvent evt) {
    initialClick = evt.getPoint();
}

private void thisMouseDragged(MouseEvent evt) {
    int thisX = this.getLocation().x;
    int thisY = this.getLocation().y;
    int xMoved = (thisX + evt.getX()) - (thisX + initialClick.x);
    int yMoved = (thisY + evt.getY()) - (thisY + initialClick.y);
    int x = thisX + xMoved;
    int y = thisY + yMoved;
    this.setLocation(x, y);
}

private void jLabelExitMouseClicked() {
    close();
}

private void close() {
    end = true;
    FadeTransitions.fadeOut(this, FadeTransitions.FAST_FADE, FadeTransitions.EXIT_ON_CLOSE);
}

private void jLabelExitMouseEntered() {
    jPanelExit.setBackground(new Color(200, 0, 20));
}

private void jLabelExitMouseExited() {
    jPanelExit.setBackground(new Color(160, 0, 20));
}

private void jButtonGoActionPerformed() {
    end = true;
    FadeTransitions.run(this, new ServerManager(this), FadeTransitions.NORMAL_FADE, FadeTransitions.DISPOSE_ON_CLOSE);
}

}

谢谢。

最佳答案

抱歉，不是一个答案，但是希望至少朝着可接受的答案迈出一步:到目前为止，根据我的分析，可能这只是渲染管道内部某个深处(深处!)的错误。

以下MVCE显示了两个(未装饰的)帧，每个帧都包含一个按钮。它们是相同的，除了框架的背景。对于一帧，颜色是透明的，而对于另一帧，颜色是不透明的。

import java.awt.Color;
import java.awt.Font;

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.SwingUtilities;
import javax.swing.UIManager;

public class TextRenderBug extends JFrame {

    public static void main(String[] args)
    {
        setLookAndFeel();
        SwingUtilities.invokeLater(new Runnable()
        {
            @Override
            public void run()
            {
                createAndShowGUI(new Color(0,0,0  ), 400);
                createAndShowGUI(new Color(0,0,0,0), 600);
            }
        });
    }

    private static void setLookAndFeel()
    {
        try
        {
            for (UIManager.LookAndFeelInfo info :
                    UIManager.getInstalledLookAndFeels())
            {
                if ("Nimbus".equals(info.getName()))
                {
                    UIManager.setLookAndFeel(info.getClassName());
                    break;
                }
            }
        }
        catch (Exception e)
        {
            e.printStackTrace();
        }
    }

    private static void createAndShowGUI(Color background, int x)
    {
        JFrame f = new JFrame();
        f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        f.setUndecorated(true);
        f.setBackground(background);
        JButton b = new JButton("Text");
        b.setFont(new Font("Tahoma", 0, 15));
        f.getContentPane().add(b);
        f.setBounds(x, 400, 200, 50);
        f.setVisible(true);
    }
}

它清楚地表明，文本的呈现方式有所不同，完全取决于背景是否透明-当然，情况并非如此。

(顺便说一下，这不是特定于Nimbus的:它也适用于其他LookAndFeels。只需删除设置LaF的行)。

到目前为止，我发现了什么:

该行为是由drawString类

的sun.swing.SwingUtilities2方法引起的

它并不出现在所有组件中。可以在JButton和JLabel上看到它，但是在普通JComponent上却看不到

更新:它也不依赖于字体(尽管与其他字体一样，效果也不那么明显)。正确呈现后，字体看起来会有点粗体，但是，当然，它不仅仅是与Font.BOLD相同的字体。

绘画过程相当复杂。

(好的，你们中有些人可能已经知道后者)。

这是一个显示最后观察结果的示例，也许它可以作为其他研究的起点:

import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.GridLayout;
import java.lang.reflect.Method;

import javax.swing.JButton;
import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.SwingUtilities;

public class TextRenderBugTest
{
    public static void main(String[] args)
    {
        SwingUtilities.invokeLater(new Runnable()
        {
            @Override
            public void run()
            {
                createAndShowGUI(new Color(0,0,0  ), 400);
                createAndShowGUI(new Color(0,0,0,0), 600);
            }
        });
    }

    private static void createAndShowGUI(Color background, int x)
    {
        JFrame f = new JFrame();
        f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        f.setUndecorated(true);
        f.setBackground(background);

        JButton b = new JButton("Text");
        b.setFont(new Font("Tahoma", 0, 15));

        JComponent c = new ExampleComponent();
        c.setFont(new Font("Tahoma", 0, 15));

        f.getContentPane().setLayout(new GridLayout(0,1));
        f.getContentPane().add(b);
        f.getContentPane().add(c);

        f.setBounds(x, 400, 200, 100);
        f.setVisible(true);
    }

    static class ExampleComponent
        //extends JComponent
        extends JButton
    {
        @Override
        protected void paintComponent(Graphics g)
        {
            super.paintComponent(g);
            g.setColor(getBackground());
            g.fillRect(0, 0, getWidth(), getHeight());
            g.setColor(getForeground());
            g.drawString("Text", 10, 20);
            drawStringWithSwingUtilities(g, 60, 20);
        }

        private void drawStringWithSwingUtilities(Graphics g, int x, int y)
        {
            try
            {
                Class<?> c = Class.forName("sun.swing.SwingUtilities2");
                Method m = c.getMethod("drawString", JComponent.class,
                    Graphics.class, String.class, int.class, int.class);
                m.invoke(null, this, g, "Text", x, y);
            }
            catch (Exception e)
            {
                e.printStackTrace();
            }

        }

    }

}

我已经尝试进一步分析此问题，并尝试使用RenderingHints(例如KEY_TEXT_ANTIALIASING和KEY_TEXT_LCD_CONTRAST)以及其他在绘制管道中更改的设置，同时它们将朝着最终放置在屏幕上的像素前进，但到目前为止没有更多的见解。

(如果愿意，可以将此信息添加到原始问题中，然后我将删除此(非)答案)