为什么图像要旋转并调整大小而不是仅调整大小？

我想调整图像大小而不旋转图像 这是我的代码。

Image temp = image.getScaledInstance(width, height,ImageScale.SCALE_SMOOTH);
BufferedImage resized = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
Graphics2D g2d = resized.createGraphics();
g2d.drawImage(temp, 0, 0, width, height, null);
g2d.dispose();
return resized;

当您调整图像大小时，写入的新图像不包含 EXIF 数据，因此它显示为原始图像，这使得它看起来像是在侧面。

我有一个示例代码向您展示如何保留 EXIF 数据：

public class ImageData {

public byte[] resize(int maxDimension, File imageFile) throws IOException {
    DataInputStream inStream = null;
    try {
        inStream = new DataInputStream(
                new BufferedInputStream(
                        new FileInputStream(imageFile)));

        byte[] imageData = IOUtils.toByteArray(inStream);

        BufferedImage image = readImage(imageData);

        TiffImageMetadata metadata = readExifMetadata(imageData);

        image = Scalr.resize(image, maxDimension);

        if (metadata != null) {
            imageData = writeExifMetadata(metadata, writeJPEG(image));

        } else {
            imageData = writePNG(image);
        }

        return imageData;

    } catch (IOException | ImageReadException | ImageWriteException e) {
        log.error("image resize failed", e);
        return null;
    } finally {
        assert inStream != null;
        inStream.close();
    }
}

private TiffImageMetadata readExifMetadata(byte[] jpegData) throws ImageReadException, IOException {
    ImageMetadata imageMetadata = Imaging.getMetadata(jpegData);
    if (imageMetadata == null) {
        return null;
    }
    JpegImageMetadata jpegMetadata = (JpegImageMetadata)imageMetadata;
    return jpegMetadata.getExif();
}

private byte[] writeExifMetadata(TiffImageMetadata metadata, byte[] jpegData)
        throws ImageReadException, ImageWriteException, IOException {
    ByteArrayOutputStream out = new ByteArrayOutputStream();
    new ExifRewriter().updateExifMetadataLossless(jpegData, out, metadata.getOutputSet());
    out.close();
    return out.toByteArray();
}

private BufferedImage readImage(byte[] data) throws IOException {
    return ImageIO.read(new ByteArrayInputStream(data));
}

private byte[] writeJPEG(BufferedImage image) throws IOException {
    ByteArrayOutputStream jpegOut = new ByteArrayOutputStream();
    ImageIO.write(image, "JPEG", jpegOut);
    jpegOut.close();
    return jpegOut.toByteArray();
}

/**
 *
 * @param image
 * @return byte[]
 * @throws IOException
 * This method calls when the metadata of a JPEG image is null,
 * it will convert the JPEG image to PNG
 */
private byte[] writePNG(BufferedImage image) throws IOException {
    ByteArrayOutputStream pngOut = new ByteArrayOutputStream();
    ImageIO.write(image,"PNG",  pngOut);
    pngOut.close();
    return pngOut.toByteArray();
}

}

你可以像这样使用这个类：

 public String convertImageToThumbnail(String path) {
    try {
        File imageFile = new File(path);
        byte[] imageBytes;
        String ex = path.substring(path.lastIndexOf(".")+1);

       ImageData imageData = new ImageData();
       imageBytes = imageData.resize(50, imageFile);
        
        String output = Base64.getEncoder().encodeToString(imageBytes);
        return "data:image/"+ex+";base64," + output;
    } catch (Exception e) {
        log.error("Converting to thumbnail failed", e);
        return null;
    }
}

您可以使用此示例调整大小并保留 EXIF 数据。 希望它会有用...