java BufferedImage 产生黑色背景
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BufferedImage producing black background
提问by Josh M
Alright so I'm making a game, and I'm trying to modify the original hit marker image by adding text on it, and I'm using the following code:
好的，所以我正在制作一个游戏，我正在尝试通过在其上添加文本来修改原始命中标记图像，并且我正在使用以下代码：
import javax.swing.ImageIcon;
import javax.swing.Timer;
import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics2D;
import java.awt.Image;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.image.BufferedImage;
public class HitMarker {
public static final Image rangeHitMarker = new ImageIcon(HitMarker.class.getResource("rangeHitMarker.png")).getImage();
public static final Image magicHitMarker = new ImageIcon(HitMarker.class.getResource("magicHitMarker.png")).getImage();
public static final Image monsterHitMarker = new ImageIcon(HitMarker.class.getResource("monsterHitMarker.png")).getImage();
public static final Font font = new Font("Tahoma", Font.PLAIN, 10);
public static final Color t = new Color(0,0,0,0);
public Image hitMarker;
public BufferedImage image;
public String hit;
public int attackStyle;
public boolean rangeAttack;
public int x;
public int y;
public Timer timer;
public boolean remove;
public HitMarker(int x, int y, int hit, int attackStyle){
this.hit = String.format("%d", hit);
this.remove = false;
this.x = x;
this.y = y;
this.attackStyle = attackStyle;
this.hitMarker = getImage();
BufferedImage bi = new BufferedImage(35, 20, BufferedImage.TYPE_INT_RGB);
Graphics2D g = bi.createGraphics();
g.drawImage(hitMarker, 0, 0, null);
g.setFont(font);
g.setColor(Color.WHITE);
g.drawString(this.hit, 18, 13);
g.dispose();
image = bi;
timer = new Timer(800,
new ActionListener(){
public void actionPerformed(ActionEvent e){
remove = true;
timer.stop();
}
}
);
timer.setInitialDelay(800);
timer.start();
}
public HitMarker(int x, int y, int hit){
this.hit = String.format("%d", hit);
this.remove = false;
this.x = x;
this.y = y;
this.hitMarker = monsterHitMarker;
BufferedImage bi = new BufferedImage(35, 20, BufferedImage.TYPE_INT_RGB);
Graphics2D g = bi.createGraphics();
g.drawImage(hitMarker, 0, 0, null);
g.setFont(font);
g.setColor(Color.WHITE);
g.drawString(this.hit, 18, 13);
g.dispose();
image = bi;
timer = new Timer(800,
new ActionListener(){
public void actionPerformed(ActionEvent e){
remove = true;
timer.stop();
}
}
);
timer.setInitialDelay(800);
timer.start();
}
public boolean isRangeAttack(){
return attackStyle == AttackStyleConstants.RANGE || attackStyle == AttackStyleConstants.RANGE_DEFENCE ? true : false;
}
public Image getImage(){
return isRangeAttack() ? rangeHitMarker : magicHitMarker;
}
}
Focusing particularly on either constructor: And the error that I'm having is that when I create the BufferedImage and draw the image on the buffered image, it's creating a black background automatically and I don't know why. I've tried researching on this topic and some say to change something about the AlphaComposite and the g.clearRect() method, but neither of those seem to work. By the way, the image that I'm painting on the buffered image is 35x20 (which is the dimensions of the buffered image) and it has a transparent background. If anyone can tell me how to remove this black background, it would be very much appreciated, thank you.
特别关注任一构造函数：我遇到的错误是，当我创建 BufferedImage 并在缓冲图像上绘制图像时，它会自动创建黑色背景，我不知道为什么。我试过研究这个话题，有人说要改变一些关于 AlphaComposite 和 g.clearRect() 方法的东西，但这些似乎都不起作用。顺便说一下，我在缓冲图像上绘制的图像是 35x20（这是缓冲图像的尺寸）并且它具有透明背景。如果有人能告诉我如何删除这个黑色背景，将不胜感激，谢谢。
回答by Clint
Try BufferedImage.TYPE_INT_ARGB. This will make the regions transparent instead of black.
试试BufferedImage.TYPE_INT_ARGB。这将使区域透明而不是黑色。
回答by Andrew
You might want to try and store the alpha channel as well,
您可能还想尝试存储 Alpha 通道，
BufferedImage bi = new BufferedImage(35, 20, BufferedImage.TYPE_INT_ARGB);
回答by IvanRF
If you need a JPGwith whitebackground, you need to draw the image like this:
如果你需要一个JPG与白色的背景，你需要画的图像是这样的：
g.drawImage(hitMarker, 0, 0, Color.WHITE, null);
This way you avoid the black background when going from PNGto JPG.
这样你就可以在从PNG到时避免黑色背景JPG。
回答by burakim
Use png instead of jpeg. Png is much suitable for transparency operations. Here is simple png export code snippet;
使用 png 而不是 jpeg。Png 非常适合透明操作。这是简单的 png 导出代码片段；
BufferedImage bImage = new BufferedImage(640, 480, BufferedImage.TYPE_INT_ARGB);
Graphics2D g2d = (Graphics2D) bImage.getGraphics();
DrawingContext context = new DrawingContext(g2d);
plot.draw(context);
ByteArrayOutputStream baos = new ByteArrayOutputStream();
DrawableWriter wr = DrawableWriterFactory.getInstance().get("image/png");
wr.write(plot, baos, 640, 480);
baos.flush();
baos.close();
InputStream inputStream = new ByteArrayInputStream(baos.toByteArray());
BufferedImage bufferedImage = ImageIO.read(inputStream);
ImageIO.write(bufferedImage,"png",new File(outputFolder.getPath()+"/result.png"));
