透明 BufferedImage 在 JLabel 上绘制时显示为黑色背景
我有一个从 png 文件创建的 BufferedImage。创建它时，我将类型设置为 TYPE_INT_ARGB，这应该给我一个透明图像。当我在 JPanel 中使用 PaintComponent 来绘制图像时，我得到的图像具有黑色背景。我真的需要让它透明，这样任何帮助都会有用。为了清楚起见，这里是代码：
public class ImagePanel extends JPanel {
private static final long serialVersionUID = 1L;
private BufferedImage image;
public ImagePanel() {
this.image = null;
}
public void createImage(String fileName) {
this.image = ImageUtilities.getBufferedImage(fileName, this);
this.repaint();
}
public void paint(Graphics g) {
g.drawImage(this.image, 0, 0, this);
}
}
这是我加载图像的方式：
public class ImageUtilities {
/** Create Image from a file, then turn that into a BufferedImage.
*/
public static BufferedImage getBufferedImage(String imageFile, Component c) {
Image image = c.getToolkit().getImage(imageFile);
waitForImage(image, c);
BufferedImage bufferedImage = new BufferedImage(image.getWidth(c), image.getHeight(c),
BufferedImage.TYPE_INT_ARGB);
Graphics2D g2d = bufferedImage.createGraphics();
g2d.drawImage(image, 0, 0, c);
return(bufferedImage);
}
最后要添加的一件事是，此 ImagePanel 位于另一个面板内，如果这有任何意义的话。
I've got a BufferedImage which is created from a png file. When creating it I set the type to be TYPE_INT_ARGB which should give me a transparent image. When I use paintComponent inside a JPanel to paint the image, I get the image with a black background. I really need to get it transparent so any help will be useful. Here is the code for clarity:
public class ImagePanel extends JPanel {
private static final long serialVersionUID = 1L;
private BufferedImage image;
public ImagePanel() {
this.image = null;
}
public void createImage(String fileName) {
this.image = ImageUtilities.getBufferedImage(fileName, this);
this.repaint();
}
public void paint(Graphics g) {
g.drawImage(this.image, 0, 0, this);
}
}
Here is how I load the image:
public class ImageUtilities {
/** Create Image from a file, then turn that into a BufferedImage.
*/
public static BufferedImage getBufferedImage(String imageFile, Component c) {
Image image = c.getToolkit().getImage(imageFile);
waitForImage(image, c);
BufferedImage bufferedImage = new BufferedImage(image.getWidth(c), image.getHeight(c),
BufferedImage.TYPE_INT_ARGB);
Graphics2D g2d = bufferedImage.createGraphics();
g2d.drawImage(image, 0, 0, c);
return(bufferedImage);
}
And one last thing to add is that this ImagePanel is inside another Panel, if that has any significance.
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评论（3）
不确定这是否能解决您的问题，但是：
Not sure if this will solve your problem, but:
您是否被限制使用旧版本的 Java？尝试使用 ImageIO.read(fileName) 加载图像文件。
Are you restricted to using an older version of Java? Try using ImageIO.read(fileName) to load the image file.
试试这个（即 setComposite()）：
g2d.setComposite(AlphaComposite.SrcOver);
g2d.setPaint(backgroundColor);
g2d.fillRect(0, 0, w, h);
Try this (i.e. setComposite()):
g2d.setComposite(AlphaComposite.SrcOver);
g2d.setPaint(backgroundColor);
g2d.fillRect(0, 0, w, h);