Image Transparency

How to make an image transparent in Java?

Here is one method for making a specific color transparent for any image.

public BufferedImage clearColor(Image image, Color color) {
 int width = image.getWidth(null);
 int height = image.getHeight(null);

 BufferedImage bImg =
  new BufferedImage(width, height,
   BufferedImage.TYPE_INT_ARGB);

 // transfer the source image a new 32 bit per pixel
 // image need to give some images a 8 bit alpha
 // channel, makes our images uniform, color depth
 Graphics g = bImg.getGraphics();
 g.drawImage(image, 0, 0, null);

 // go through all the colors
 int total = width * height;
 int x = 0, y = 0;
 int c[] = new int[4];

 WritableRaster wr = bImg.getRaster();
 for (int i = 0; i < total; ++i) {
  // avoid nested loops
  y = i / width; // truncated
  x = i - y * width;    
  wr.getPixel(x, y, c);
  if (c[2] == color.getBlue() &&
   c[1] == color.getGreen() &&
   c[0] == color.getRed()) {

     //clear the color at x,y    
   bImg.setRGB(x, y, 0);
  }
 }
 return bImg;
}

Another method would be to edit the image in an image editor and make the background color transparent saving the image to a format that supports transparency.

Here is the example snippet:

• TransparencyDemo.java