java 如何在java中将图像转换为透明图像
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How to convert an image into a transparent image in java
提问by SWDeveloper
How to convert a white background of an image into a transparent background? Can anyone tel me how to do this?
如何将图像的白色背景转换为透明背景？谁能告诉我如何做到这一点？
回答by tim_yates
The first result from Google is this:
谷歌的第一个结果是这样的：
Make a color transparent http://www.rgagnon.com/javadetails/java-0265.html
使颜色透明 http://www.rgagnon.com/javadetails/java-0265.html
It makes the Blue part of an image transparent, but I'm sure you can adapt that to use White intstead
它使图像的蓝色部分透明，但我相信您可以将其改为使用白色
(hint: Pass Color.WHITEto the makeColorTransparentfunction, instead of Color.BLUE)
（提示：传递Color.WHITE给makeColorTransparent函数，而不是Color.BLUE）
Found a more complete and modern answer here: How to make a color transparent in a BufferedImage and save as PNG
在这里找到了一个更完整和现代的答案：How to make a color transparent in a BufferedImage and save as PNG
回答by Ruchi
This method will make background transparent. You need to pass the image you want to modify, colour, and tolerance.
此方法将使背景透明。您需要传递要修改的图像，颜色和容差。
final int color = ret.getRGB(0, 0);
final Image imageWithTransparency = makeColorTransparent(ret, new Color(color), 10);
final BufferedImage transparentImage = imageToBufferedImage(imageWithTransparency);
private static BufferedImage imageToBufferedImage(final Image image) {
final BufferedImage bufferedImage =
new BufferedImage(image.getWidth(null), image.getHeight(null), BufferedImage.TYPE_INT_ARGB);
final Graphics2D g2 = bufferedImage.createGraphics();
g2.drawImage(image, 0, 0, null);
g2.dispose();
return bufferedImage;
}
private static Image makeColorTransparent(final BufferedImage im, final Color color, int tolerance) {
int temp = 0;
if (tolerance < 0 || tolerance > 100) {
System.err.println("The tolerance is a percentage, so the value has to be between 0 and 100.");
temp = 0;
} else {
temp = tolerance * (0xFF000000 | 0xFF000000) / 100;
}
final int toleranceRGB = Math.abs(temp);
final ImageFilter filter = new RGBImageFilter() {
// The color we are looking for (white)... Alpha bits are set to opaque
public int markerRGBFrom = (color.getRGB() | 0xFF000000) - toleranceRGB;
public int markerRGBTo = (color.getRGB() | 0xFF000000) + toleranceRGB;
public final int filterRGB(final int x, final int y, final int rgb) {
if ((rgb | 0xFF000000) >= markerRGBFrom && (rgb | 0xFF000000) <= markerRGBTo) {
// Mark the alpha bits as zero - transparent
return 0x00FFFFFF & rgb;
} else {
// Nothing to do
return rgb;
}
}
};
final ImageProducer ip = new FilteredImageSource(im.getSource(), filter);
return Toolkit.getDefaultToolkit().createImage(ip);
}
回答by Bob
Here is my solution. This filter will remove the background from any image as long as the background image color is in the top left corner.
这是我的解决方案。只要背景图像颜色位于左上角，此过滤器就会从任何图像中删除背景。
private static class BackgroundFilter extends RGBImageFilter{
boolean setUp = false;
int bgColor;
@Override
public int filterRGB(int x, int y, int rgb) {
int colorWOAlpha = rgb & 0xFFFFFF;
if( ! setUp && x == 0 && y == 0 ){
bgColor = colorWOAlpha;
setUp = true;
}
else if( colorWOAlpha == bgColor )
return colorWOAlpha;
return rgb;
}
}
Elsewhere...
别处...
ImageFilter bgFilter = new BackgroundFilter();
ImageProducer ip = new FilteredImageSource(image.getSource(), bgFilter);
image = Toolkit.getDefaultToolkit().createImage(ip);
