我一直在网上搜索这个问题,但是没有找到有用的帮助。
我有一个BufferedImage,通过ImageIO读取。现在我想要把这个图片中的某个颜色变成透明,并将其保存为PNG文件。
我知道我不能仅仅“绘制”透明颜色,因为这是不可能的,所以我猜我需要一些滤镜。
有人有相关示例代码吗?
我一直在网上搜索这个问题,但是没有找到有用的帮助。
我有一个BufferedImage,通过ImageIO读取。现在我想要把这个图片中的某个颜色变成透明,并将其保存为PNG文件。
我知道我不能仅仅“绘制”透明颜色,因为这是不可能的,所以我猜我需要一些滤镜。
有人有相关示例代码吗?
最近我为了回答我的项目经理的一个问题,进行了这样的操作。
将灰度转换为透明的函数是:
private Image TransformGrayToTransparency(BufferedImage image)
{
ImageFilter filter = new RGBImageFilter()
{
public final int filterRGB(int x, int y, int rgb)
{
return (rgb << 8) & 0xFF000000;
}
};
ImageProducer ip = new FilteredImageSource(image.getSource(), filter);
return Toolkit.getDefaultToolkit().createImage(ip);
}
实际上,它作用于灰度图像,所以我只是将RGB组件(R)复制到alpha通道中,丢弃在我的情况下相同的其他组件。
您可以使其适应过滤特定颜色,例如通过相等或范围测试等。
当然,BufferedImage必须是BufferedImage.TYPE_INT_ARGB类型。
至于保存的问题,我不解决,因为它很简单,但我也可以添加这个代码页。
[编辑] 将Image转换为BufferedImage:
BufferedImage dest = new BufferedImage(
imageWidth, imageHeight,
BufferedImage.TYPE_INT_ARGB);
Graphics2D g2 = dest.createGraphics();
g2.drawImage(image, 0, 0, null);
g2.dispose();
[编辑2] 我在Christoffer发布完整解决方案之后发表了自己的观点,这里是我的解决方案,展示如何使一系列颜色透明。可以改进,例如使用HSB组件代替。
import java.awt.*;
import java.awt.image.BufferedImage;
import java.awt.image.FilteredImageSource;
import java.awt.image.ImageFilter;
import java.awt.image.ImageProducer;
import java.awt.image.RGBImageFilter;
import java.io.*;
import javax.imageio.ImageIO;
public class AddTransparency
{
AddTransparency() throws IOException
{
String imagePath = "E:/Documents/images/";
File inFile = new File(imagePath, "map.png");
BufferedImage image = ImageIO.read(inFile);
Image transpImg1 = TransformGrayToTransparency(image);
BufferedImage resultImage1 = ImageToBufferedImage(transpImg1, image.getWidth(), image.getHeight());
File outFile1 = new File(imagePath, "map_with_transparency1.png");
ImageIO.write(resultImage1, "PNG", outFile1);
Image transpImg2 = TransformColorToTransparency(image, new Color(0, 50, 77), new Color(200, 200, 255));
BufferedImage resultImage2 = ImageToBufferedImage(transpImg2, image.getWidth(), image.getHeight());
File outFile2 = new File(imagePath, "map_with_transparency2.png");
ImageIO.write(resultImage2, "PNG", outFile2);
}
private Image TransformGrayToTransparency(BufferedImage image)
{
ImageFilter filter = new RGBImageFilter()
{
public final int filterRGB(int x, int y, int rgb)
{
return (rgb << 8) & 0xFF000000;
}
};
ImageProducer ip = new FilteredImageSource(image.getSource(), filter);
return Toolkit.getDefaultToolkit().createImage(ip);
}
private Image TransformColorToTransparency(BufferedImage image, Color c1, Color c2)
{
// Primitive test, just an example
final int r1 = c1.getRed();
final int g1 = c1.getGreen();
final int b1 = c1.getBlue();
final int r2 = c2.getRed();
final int g2 = c2.getGreen();
final int b2 = c2.getBlue();
ImageFilter filter = new RGBImageFilter()
{
public final int filterRGB(int x, int y, int rgb)
{
int r = (rgb & 0xFF0000) >> 16;
int g = (rgb & 0xFF00) >> 8;
int b = rgb & 0xFF;
if (r >= r1 && r <= r2 &&
g >= g1 && g <= g2 &&
b >= b1 && b <= b2)
{
// Set fully transparent but keep color
return rgb & 0xFFFFFF;
}
return rgb;
}
};
ImageProducer ip = new FilteredImageSource(image.getSource(), filter);
return Toolkit.getDefaultToolkit().createImage(ip);
}
private BufferedImage ImageToBufferedImage(Image image, int width, int height)
{
BufferedImage dest = new BufferedImage(
width, height, BufferedImage.TYPE_INT_ARGB);
Graphics2D g2 = dest.createGraphics();
g2.drawImage(image, 0, 0, null);
g2.dispose();
return dest;
}
public static void main(String[] args) throws IOException
{
AddTransparency at = new AddTransparency();
}
}
感谢 PhilLo,这里是我演示应用的完整解决方案。
public static void main(String[] args) throws Exception {
File in = new File("C:\\Users\\Christoffer\\Desktop\\christoffer.jpg");
BufferedImage source = ImageIO.read(in);
int color = source.getRGB(0, 0);
Image image = makeColorTransparent(source, new Color(color));
BufferedImage transparent = imageToBufferedImage(image);
File out = new File("C:\\Users\\Christoffer\\Desktop\\trans.PNG");
ImageIO.write(transparent, "PNG", out);
}
private static BufferedImage imageToBufferedImage(Image image) {
BufferedImage bufferedImage = new BufferedImage(image.getWidth(null), image.getHeight(null), BufferedImage.TYPE_INT_ARGB);
Graphics2D g2 = bufferedImage.createGraphics();
g2.drawImage(image, 0, 0, null);
g2.dispose();
return bufferedImage;
}
public static Image makeColorTransparent(BufferedImage im, final Color color) {
ImageFilter filter = new RGBImageFilter() {
// the color we are looking for... Alpha bits are set to opaque
public int markerRGB = color.getRGB() | 0xFF000000;
public final int filterRGB(int x, int y, int rgb) {
if ((rgb | 0xFF000000) == markerRGB) {
// Mark the alpha bits as zero - transparent
return 0x00FFFFFF & rgb;
} else {
// nothing to do
return rgb;
}
}
};
ImageProducer ip = new FilteredImageSource(im.getSource(), filter);
return Toolkit.getDefaultToolkit().createImage(ip);
}
rgb
参数是4个有意义的字节还是只有3个。透明度是从哪里来的?是从3个字节中的魔数还是第4个字节中的值? - Nikolay Kuznetsovreturn rgb&0xFFFFFF;
我认为应该是return rgb&0xFFFFFFFF;
关于你的第一个代码块。干杯;-) - kisp