如何使绘制的图像在Java中透明 [英] How to make drawn images transparent in Java

问题描述

我让动画在Snake Clone Game中运行。但基于图片的问题是图像没有透明度（请注意圆形图片的白色背景。编程方面，是否有修复能够包含这些绘制图像的透明度？

I got the animation to work in my Snake Clone Game. But the problem based on the picture is that the images do not have transparency(notice the white background of the circle pictures. Programming-wise, is there a fix to be able to include transparency to these drawn images?

这是一张包含我的代码和程序输出的图片。

Here's a picture containing my code and the output of the program.

PS在旁注中，我决定粘贴直接链接而不是IMG代码因为我似乎无法在StackOverFlow上显示它。我在IMG代码的前面放了一个感叹号，但它没有用，所以这里是直接链接。

P.S. On a side note, I decided to paste the direct link instead of the IMG code because I cannot seem to get it to display on StackOverFlow. I put an exclamation point in the front of the IMG code but it did not work so here's the direct link.

推荐答案

正如另一个提到的答案，最简单的方法可能是简单地使用具有透明背景的PNG图像（您可以使用像GIMP这样的图像编辑器创建这些图像）。或者，如果您是限于具有坚实背景的PNG图像，这是一个例子le如何改变给定的颜色（例如PNG中的白色）透明：

As the other answer mentioned, the easiest way would probably be to simply use PNG images which have a transparent background (you can create these with an image editor like GIMP). Alternatively, if you are limited to PNG images with a solid background, here's an example of how to change a given color (e.g. white) in the PNG to transparent:

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

public class SimpleFrame extends JFrame {
   JPanel mainPanel = new JPanel() {
      ImageIcon originalIcon = new ImageIcon("~/Pictures/apple.png");

      ImageFilter filter = new RGBImageFilter() {
         int transparentColor = Color.white.getRGB() | 0xFF000000;

         public final int filterRGB(int x, int y, int rgb) {
            if ((rgb | 0xFF000000) == transparentColor) {
               return 0x00FFFFFF & rgb;
            } else {
               return rgb;
            }
         }
      };

      ImageProducer filteredImgProd = new FilteredImageSource(originalIcon.getImage().getSource(), filter);
      Image transparentImg = Toolkit.getDefaultToolkit().createImage(filteredImgProd);

      public void paintComponent(Graphics g) {
         g.setColor(getBackground());
         g.fillRect(0, 0, getSize().width, getSize().height);

         // draw the original icon
         g.drawImage(originalIcon.getImage(), 100, 10, this);
         // draw the transparent icon
         g.drawImage(transparentImg, 140, 10, this);
      }
   };

   public SimpleFrame() {
      super("Transparency Example");

      JPanel content = (JPanel)getContentPane();
      mainPanel.setBackground(Color.black);
      content.add("Center", mainPanel);
   }

   public static void main(String[] argv) {
      SwingUtilities.invokeLater(new Runnable() {
         public void run() {
            SimpleFrame c = new SimpleFrame();
            c.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
            c.setSize(280,100);
            c.setVisible(true);
         }
      });
   }
}

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