如何在paintComponent方法中向图像添加颜色层? [英] How to add a color layer to the image in paintComponent method?

问题描述

我用Java编写了第一款游戏.所以我有Board类扩展了JPanel，在这个类中我有paintComponent方法.卡片图像是BufferedImages.

I write my first game in Java. So I have Board class extends JPanel, and inside this class I have paintComponent method. Cards images are BufferedImages.

现在...我刚刚完成了计算玩家可能移动的方法.为了明确起见，我有敌方牌场，并且每当敌方CardField在玩家移动范围内时，我想在敌方cardField图像中添加一些图层.

Now... I just finished method, that calculate possible player moves. To clarify, I have enemy card Fields, and I want to add some layer to enemy cardField image every time when enemy CardField is within player move.

我在paintComponent方法中的代码是这样的:

My code in paintComponent method is something like this:

if(!field.isWithinMove()){
//draw normal state card
  g.drawImage(field.getLoadedCard().getCardImage(),
  field.getX(), field.getY(), Card.cardWidth, Card.cardHeight, null);
}
else{
 //there should be a card picture with layer of color 
}

我的目标是:

正常:

突出显示:

感谢您的帮助:)

干杯！

推荐答案

例如，您可以利用AlphaComposite更改图形的呈现方式.

You could make use of a AlphaComposite to change the way in which the graphics are rendered, for example...

import java.awt.AlphaComposite;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.imageio.ImageIO;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;

public class Test {

    public static void main(String[] args) {
        new Test();
    }

    public Test() {
        EventQueue.invokeLater(new Runnable() {
            @Override
            public void run() {
                try {
                    UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
                } catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
                    ex.printStackTrace();
                }

                JFrame frame = new JFrame("Testing");
                frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
                frame.add(new TestPane());
                frame.pack();
                frame.setLocationRelativeTo(null);
                frame.setVisible(true);
            }
        });
    }

    public class TestPane extends JPanel {

        private BufferedImage img;

        public TestPane() {
            try {
                img = ImageIO.read(source of your image here);
            } catch (IOException ex) {
                Logger.getLogger(JavaApplication393.class.getName()).log(Level.SEVERE, null, ex);
            }
        }

        @Override
        public Dimension getPreferredSize() {
            return new Dimension(189 * 2, 270);
        }

        @Override
        protected void paintComponent(Graphics g) {
            super.paintComponent(g);
            Graphics2D g2d = (Graphics2D) g.create();
            // Normal
            g2d.drawImage(img, 0, 0, this);
            // Highlighted
            g2d.drawImage(img, img.getWidth(), 0, this);
            g2d.setComposite(AlphaComposite.SrcOver.derive(0.5f));
            g2d.setColor(UIManager.getColor("List.selectionBackground"));
            g2d.fillRect(img.getWidth(), 0, img.getWidth(), img.getHeight());
            g2d.dispose();
        }

    }

}

现在，您实际上可以预渲染此图像(具有正常"和突出显示"的图像)，但这取决于您的需求

Now, you could actually pre-render this (have a "normal" and "highlighted" image), but that comes down to your needs

nb:我使用了当前外观的List.selectionBackground颜色作为填充色，您可以将其替换为所需的任何颜色

nb: I've used the List.selectionBackground color from the current look and feel for the fill color, you can replace it with what ever color you want

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