获取图像方向并根据方向旋转

本文关键字：方向 旋转 图像 获取 | 更新日期: 2023-09-27 18:36:54

使用以下

代码获取图像方向时遇到问题

    string fileName = @"D:'...'...'01012015004435.jpeg";
    int rotate = 0;
    using (var image = System.Drawing.Image.FromFile(fileName))
    {
        foreach (var prop in image.PropertyItems)
        {
            if (prop.Id == 0x112)
            {
                if (prop.Value[0] == 6)
                    rotate = 90;
                if (prop.Value[0] == 8)
                    rotate = -90;
                if (prop.Value[0] == 3)
                    rotate = 180;
                prop.Value[0] = 1;
            }
        }
    }

获得正确的方向后，我曾经像旋转图像一样

private static RotateFlipType OrientationToFlipType(string orientation)
{
    switch (int.Parse(orientation))
    {
        case 1:
            return RotateFlipType.RotateNoneFlipNone;
            break;
        case 2:
            return RotateFlipType.RotateNoneFlipX;
            break;
        case 3:
            return RotateFlipType.Rotate180FlipNone;
            break;
        case 4:
            return RotateFlipType.Rotate180FlipX;
            break;
        case 5:
            return RotateFlipType.Rotate90FlipX;
            break;
        case 6:
            return RotateFlipType.Rotate90FlipNone;
            break;
        case 7:
            return RotateFlipType.Rotate270FlipX;
            break;
        case 8:
            return RotateFlipType.Rotate270FlipNone;
            break;
        default:
            return RotateFlipType.RotateNoneFlipNone;
    }
}

但问题出在第一个代码中

prop.Id我总是得到[20625]

prop.Id == 20625

所以不是每次都满足条件如果有任何问题或其他选择，请告诉我

谢谢

获取图像方向并根据方向旋转

其他答案和注释中可能有足够的信息来将它们放在一起，但这里有一个工作代码示例。

此扩展方法将采用System.Drawing Image，读取其Exif方向标签（如果存在），然后翻转/旋转它（如有必要）。

private const int exifOrientationID = 0x112; //274
public static void ExifRotate(this Image img)
{
    if (!img.PropertyIdList.Contains(exifOrientationID))
        return;
    var prop = img.GetPropertyItem(exifOrientationID);
    int val = BitConverter.ToUInt16(prop.Value, 0);
    var rot = RotateFlipType.RotateNoneFlipNone;
    if (val == 3 || val == 4)
        rot = RotateFlipType.Rotate180FlipNone;
    else if (val == 5 || val == 6)
        rot = RotateFlipType.Rotate90FlipNone;
    else if (val == 7 || val == 8)
        rot = RotateFlipType.Rotate270FlipNone;
    if (val == 2 || val == 4 || val == 5 || val == 7)
        rot |= RotateFlipType.RotateNoneFlipX;
    if (rot != RotateFlipType.RotateNoneFlipNone)
    {
        img.RotateFlip(rot);
        img.RemovePropertyItem(exifOrientationID);
    }
}

使用以下命令：

  • img.PropertyIdList.Contains(orientationId)检查是否存在 Exif 标记。
  • img.GetPropertyItem(orientationId)得到它（在上述检查之后，否则你会得到一个ArgumentException）。
  • img.SetPropertyItem(pItem)设置它。

我写了一个简单的帮助程序类来完成所有这些工作：你可以在这里检查完整的源代码。

其他信息和快速案例研究也可以在我博客上的以下帖子中找到：

在 NET C# 中更改 iPhone 和/或 Android 图片的图像方向

您可以使用

此链接 http://regex.info/exif.cgi 检查图像嵌入的元数据。如果在 EXIF 表中找不到"0x0112"，则图像不包含旋转属性。

也许您调整了图像的大小，此时您丢失了exif，并且想根据exif制作旋转图像，在这种情况下，您可以将exif复制到调整大小的图像中：

const string inputFileName = "input.jpg";
const string outputFileName = "output.jpg";
var newSize = new Size(640, 480);
using (var bmpInput = Image.FromFile(inputFileName))
{
    using (var bmpOutput = new Bitmap(bmpInput, newSize))
    {
        foreach (int exif in bmpInput.PropertyIdList)
            bmpOutput.SetPropertyItem(bmpInput.GetPropertyItem(exif));
        bmpOutput.Save(outputFileName, ImageFormat.Jpeg);
    }
}
这是我

使用的：

// pass in an image
ChkImage.ImageOrientation image = ChkImage.GetOrientation(picCrop.Image);

public enum ImageOrientation
{
  /// <summary>
  /// Image is correctly oriented
  /// </summary>
  Original = 1,
  /// <summary>
  /// Image has been mirrored horizontally
  /// </summary>
  MirrorOriginal = 2,
  /// <summary>
  /// Image has been rotated 180 degrees
  /// </summary>
  Half = 3,
  /// <summary>
  /// Image has been mirrored horizontally and rotated 180 degrees
  /// </summary>
  MirrorHalf = 4,
  /// <summary>
  /// Image has been mirrored horizontally and rotated 270 degrees clockwise
  /// </summary>
  MirrorThreeQuarter = 5,
  /// <summary>
  /// Image has been rotated 270 degrees clockwise
  /// </summary>
  ThreeQuarter = 6,
  /// <summary>
  /// Image has been mirrored horizontally and rotated 90 degrees clockwise.
  /// </summary>
  MirrorOneQuarter = 7,
  /// <summary>
  /// Image has been rotated 90 degrees clockwise.
  /// </summary>
  OneQuarter = 8
}

public static PropertyItem SafeGetPropertyItem(Image image, int propid)
{
  try
  {
    return image.GetPropertyItem(propid);
  }
  catch (ArgumentException)
  {
    return null;
  }
}

public static ImageOrientation GetOrientation(this Image image)
{
  PropertyItem pi = SafeGetPropertyItem(image, 0x112);
  if (pi == null || pi.Type != 3)
  {
    return ImageOrientation.Original;
  }
  return (ImageOrientation)BitConverter.ToInt16(pi.Value, 0);
}
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