在Java中设置BufferedImage alpha掩码 [英] Set BufferedImage alpha mask in Java

问题描述

我有两个从pngs加载的BufferedImages。第一个包含一个图像，第二个是图像的alpha蒙版。

我想通过应用alpha蒙版来从这两个图像创建一个组合图像。

我知道如何加载/保存图片，我只需要从两个BufferedImages到一个BufferedImage的位置，右侧是alpha您可以通过一次获取多于一个像素的RGB数据来改进解决方案（请参阅 http://java.sun.com/javase/6/docs /api/java/awt/image/BufferedImage.html ），并且不会在内部循环的每次迭代中创建三个Color对象。

  final int width = image.getWidth（）; 
 int [] imgData = new int [width]; 
 int [] maskData = new int [width]; 
 
 for（int y = 0; y< image.getHeight（）; y ++）{
 //从每张图片获取一行数据
 image.getRGB（0 ，y，width，1，imgData，0，1）; 
 mask.getRGB（0，y，width，1，maskData，0，1）; 
 //将掩码
用于（int x = 0; x  int color = imgData [x]&至0x00FFFFFF; //掩盖任何存在的字母
 int maskColor =（maskData [x]& 0x00FF0000）<< 8; //将红色转换为alpha位
 color | = maskColor; 
 imgData [x] = color; 
} 
 //替换数据
 image.setRGB（0，y，width，1，imgData，0，1）; 
} 
  

I have two BufferedImages I loaded in from pngs. The first contains an image, the second an alpha mask for the image.

I want to create a combined image from the two, by applying the alpha mask. My google-fu fails me.

I know how to load/save the images, I just need the bit where I go from two BufferedImages to one BufferedImage with the right alpha channel.

解决方案

Your solution could be improved by fetching the RGB data more than one pixel at a time(see http://java.sun.com/javase/6/docs/api/java/awt/image/BufferedImage.html), and by not creating three Color objects on every iteration of the inner loop.

final int width = image.getWidth();
int[] imgData = new int[width];
int[] maskData = new int[width];

for (int y = 0; y < image.getHeight(); y++) {
    // fetch a line of data from each image
    image.getRGB(0, y, width, 1, imgData, 0, 1);
    mask.getRGB(0, y, width, 1, maskData, 0, 1);
    // apply the mask
    for (int x = 0; x < width; x++) {
        int color = imgData[x] & 0x00FFFFFF; // mask away any alpha present
        int maskColor = (maskData[x] & 0x00FF0000) << 8; // shift red into alpha bits
        color |= maskColor;
        imgData[x] = color;
    }
    // replace the data
    image.setRGB(0, y, width, 1, imgData, 0, 1);
}

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