将 dpi 元数据写入 Java 中的 jpeg 图像
2022-09-03 14:23:27
						我正在尝试以编程方式设置Java中jpeg图像的dpi元数据。图像的来源是扫描仪,因此我从TWAIN获得水平/垂直分辨率以及图像原始数据。我想保存此信息以获得更好的打印效果。
这是我到目前为止的代码。它将原始图像(字节数组)保存到JPEG文件中,但它忽略了我通过IIOMetadata指定的X / Ydensity信息。有什么建议我做错了什么吗?
任何其他解决方案(第三方库等)也将受到欢迎。
import java.awt.image.BufferedImage;
import java.awt.image.WritableRaster;
import java.io.File;
import javax.imageio.IIOImage;
import javax.imageio.ImageIO;
import javax.imageio.ImageTypeSpecifier;
import javax.imageio.metadata.IIOMetadata;
import javax.imageio.plugins.jpeg.JPEGImageWriteParam;
import javax.imageio.stream.ImageOutputStream    
import org.w3c.dom.Element;    
import com.sun.imageio.plugins.jpeg.JPEGImageWriter;
public boolean saveJpeg(int[] byteArray, int width, int height, int dpi, String file)
{
    BufferedImage bufferedImage = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
    WritableRaster wr = bufferedImage.getRaster();
    wr.setPixels(0, 0, width, height, byteArray);
    try
    {           
        // Image writer 
        JPEGImageWriter imageWriter = (JPEGImageWriter) ImageIO.getImageWritersBySuffix("jpeg").next();
        ImageOutputStream ios = ImageIO.createImageOutputStream(new File(file));
        imageWriter.setOutput(ios);
        // Compression
        JPEGImageWriteParam jpegParams = (JPEGImageWriteParam) imageWriter.getDefaultWriteParam();
        jpegParams.setCompressionMode(JPEGImageWriteParam.MODE_EXPLICIT);
        jpegParams.setCompressionQuality(0.85f);
        // Metadata (dpi)
        IIOMetadata data = imageWriter.getDefaultImageMetadata(new ImageTypeSpecifier(bufferedImage), jpegParams);
        Element tree = (Element)data.getAsTree("javax_imageio_jpeg_image_1.0");
        Element jfif = (Element)tree.getElementsByTagName("app0JFIF").item(0);
        jfif.setAttribute("Xdensity", Integer.toString(dpi));
        jfif.setAttribute("Ydensity", Integer.toString(dpi));
        jfif.setAttribute("resUnits", "1"); // density is dots per inch         
        // Write and clean up
        imageWriter.write(data, new IIOImage(bufferedImage, null, null), jpegParams);
        ios.close();
        imageWriter.dispose();
    }
    catch (Exception e)
    {
       return false;
    }
    return true;
}
谢谢!
 
					 
				 
				    		 
				    		 
				    		 
				    		