Question

我想知道如果我不清除字符串重叠之前如何在图像上绘制新字符串之前清除先前绘制的字符串。我尝试了图形#drawRect并覆盖paintComponent（Graphics），仍然没有评估。

这是我的代码：的paintComponent（图形）

public class SplashScreen extends JLabel
{

    private static final long serialVersionUID = 5515310205953670741L;

    private static final String ROOT = "./assets/img/";

    private static final SplashScreen INSTANCE = new SplashScreen( get( new File( ROOT, "splash.png" ) ), get( new File( ROOT, "splash-bar.png" ) ) );

    private final BufferedImage background;

    private final BufferedImage foreground;

    private final JLabel label;


    private SplashScreen( BufferedImage background, BufferedImage foreground )
    {
        this.background = background;
        this.foreground = foreground;
        label = new JLabel( new ImageIcon( background ) );

        JWindow window = new JWindow();
        window.setSize( background.getWidth(), background.getHeight() );
        window.getContentPane().add( label );
        Dimension dimension = Toolkit.getDefaultToolkit().getScreenSize();
        window.setLocation( dimension.width / 2 - window.getSize().width / 2, dimension.height / 2 - window.getSize().height / 2 );
        window.setVisible( true );
    }


    public void updateStatus( String status )
    {
        Graphics g = background.getGraphics();

        g.drawString( status, 304, 301 );
        g.dispose();

        label.repaint();
    }


    public void updateBar( int width )
    {
        Graphics g = background.getGraphics();

        g.drawImage( foreground, 73, 309, width, foreground.getHeight(), null );
        g.dispose();

        label.repaint();
    }


    private static BufferedImage get( File file )
    {
        try {
            return ImageIO.read( file );
        } catch( IOException e ) {
            throw new RuntimeException( e.getMessage() );
        }
    }


    public static SplashScreen getInstance()
    {
        return INSTANCE;
    }

}

非常感谢任何帮助。： - ）

感谢。

Answer 1

您无需进行自定义绘画。

以下是使用图标在标签上绘制文字的几种不同方法：

import java.awt.*;
import javax.swing.*;
import javax.swing.text.*;

public class LabelImageText extends JPanel
{
    public LabelImageText()
    {
        JLabel label1 = new JLabel( new ColorIcon(Color.ORANGE, 100, 100) );
        label1.setText( "Easy Way" );
        label1.setHorizontalTextPosition(JLabel.CENTER);
        label1.setVerticalTextPosition(JLabel.CENTER);
        add( label1 );

        //

        JLabel label2 = new JLabel( new ColorIcon(Color.YELLOW, 200, 150) );
        label2.setLayout( new BoxLayout(label2, BoxLayout.Y_AXIS) );
        add( label2 );

        JLabel text = new JLabel( "More Control" );
        text.setAlignmentX(JLabel.CENTER_ALIGNMENT);
        label2.add( Box.createVerticalGlue() );
        label2.add( text );
        label2.add( Box.createVerticalStrut(10) );

        //

        JLabel label3 = new JLabel( new ColorIcon(Color.GREEN, 200, 150) );
        add( label3 );

        JLabel text3 = new JLabel();
        text3.setText("<html><center>Text<br>over<br>Image<center></html>");
        text3.setLocation(20, 20);
        text3.setSize(text3.getPreferredSize());
        label3.add( text3 );

        //

        JLabel label4 = new JLabel( new ColorIcon(Color.CYAN, 200, 150) );
        add( label4 );

        JTextPane textPane = new JTextPane();
        textPane.setText("Add some text that will wrap at your preferred width");
        textPane.setEditable( false );
        textPane.setOpaque(false);
        SimpleAttributeSet center = new SimpleAttributeSet();
        StyleConstants.setAlignment(center, StyleConstants.ALIGN_CENTER);
        StyledDocument doc = textPane.getStyledDocument();
        doc.setParagraphAttributes(0, doc.getLength(), center, false);
        textPane.setBounds(20, 20, 75, 100);
        label4.add( textPane );
    }

    public static class ColorIcon implements Icon
    {
        private Color color;
        private int width;
        private int height;

        public ColorIcon(Color color, int width, int height)
        {
            this.color = color;
            this.width = width;
            this.height = height;
        }

        public int getIconWidth()
        {
            return width;
        }

        public int getIconHeight()
        {
            return height;
        }

        public void paintIcon(Component c, Graphics g, int x, int y)
        {
            g.setColor(color);
            g.fillRect(x, y, width, height);
        }
    }

    private static void createAndShowUI()
    {
        JFrame frame = new JFrame("LabelImageText");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.add( new LabelImageText() );
        frame.pack();
        frame.setLocationRelativeTo( null );
        frame.setVisible( true );
    }

    public static void main(String[] args)
    {
        EventQueue.invokeLater(new Runnable()
        {
            public void run()
            {
                createAndShowUI();
            }
        });
    }
}

然后要更改文本，只需更改正在使用的组件中的文本即可显示文本。

如果这些都没有帮助那么自定义绘画的方法是覆盖JLabel的paintCompnent()方法。您不应该直接在BufferedImage上绘制文本。

Answer 2

基本上，你不能。

您应该尝试做的是保留对原始背景图像的引用，当您需要更改文本时，将其复制到临时图像并在那里绘制String，将其替换（临时副本）为标签的图标......

更好的解决方案可能是通过覆盖paintComponent方法直接将文本绘制为标签绘制过程的一部分

清除以前在图像上绘制的字符串

2 个答案: