System.Drawing.Graphics Drawimage将从IOS获取的图片旋转到90度

Question

我有下面的代码，它获取上传的图像并使用System.Drawing.Graphics在150 x 200 div中绘制它，但是当图像取自IOS设备图片右转90度。

仅供参考：我有同样的问题在JavaScript画布中绘制图像，并且This解决方案适用于我。因此，我要寻找一个在C＃中的同类解决方案

 private System.Drawing.Image ResizeAndDraw(System.Drawing.Image objTempImage) 
      { 
       Size objSize = new Size(150, 200); 
       Bitmap objBmp; 
       objBmp = new Bitmap(objSize.Width, objSize.Height); 

       Graphics g = Graphics.FromImage(objBmp); 
       g.SmoothingMode = SmoothingMode.HighQuality; 
       g.InterpolationMode = InterpolationMode.HighQualityBicubic; 
       g.PixelOffsetMode = PixelOffsetMode.HighQuality; 
       //Rectangle rect = new Rectangle(x, y, thumbSize.Width, thumbSize.Height); 
       Rectangle rect = new Rectangle(0,0,150,200); 
       //g.DrawImage(objTempImage, rect, 0, 0, objTempImage.Width, objTempImage.Height, GraphicsUnit.Pixel); 
       g.DrawImage(objTempImage, rect); 
       return objBmp; 
      } 

Answer 1

我最终解决从答案我自己贴 Here他写了一个简单的辅助类，做所有的问题：

you can check the full source code here.

private System.Drawing.Image ResizeAndDraw(System.Drawing.Image objTempImage) 
     { 
      // call image helper to fix the orientation issue 
      var temp = ImageHelper.RotateImageByExifOrientationData(objTempImage, true); 
      Size objSize = new Size(150, 200); 
      Bitmap objBmp; 
      objBmp = new Bitmap(objSize.Width, objSize.Height); 

      Graphics g = Graphics.FromImage(objBmp); 
      g.SmoothingMode = SmoothingMode.HighQuality; 
      g.InterpolationMode = InterpolationMode.HighQualityBicubic; 
      g.PixelOffsetMode = PixelOffsetMode.HighQuality; 
      //Rectangle rect = new Rectangle(x, y, thumbSize.Width, thumbSize.Height); 
      Rectangle rect = new Rectangle(0,0,150,200); 
      //g.DrawImage(objTempImage, rect, 0, 0, objTempImage.Width, objTempImage.Height, GraphicsUnit.Pixel); 
      g.DrawImage(objTempImage, rect); 
      return objBmp; 
     } 


using System.Drawing; 
using System.Drawing.Imaging; 
using System.Linq; 

public static class ImageHelper 
{ 
    /// <summary> 
    /// Rotate the given image file according to Exif Orientation data 
    /// </summary> 
    /// <param name="sourceFilePath">path of source file</param> 
    /// <param name="targetFilePath">path of target file</param> 
    /// <param name="targetFormat">target format</param> 
    /// <param name="updateExifData">set it to TRUE to update image Exif data after rotation (default is TRUE)</param> 
    /// <returns>The RotateFlipType value corresponding to the applied rotation. If no rotation occurred, RotateFlipType.RotateNoneFlipNone will be returned.</returns> 
    public static RotateFlipType RotateImageByExifOrientationData(string sourceFilePath, string targetFilePath, ImageFormat targetFormat, bool updateExifData = true) 
    { 
     // Rotate the image according to EXIF data 
     var bmp = new Bitmap(sourceFilePath); 
     RotateFlipType fType = RotateImageByExifOrientationData(bmp, updateExifData); 
     if (fType != RotateFlipType.RotateNoneFlipNone) 
     { 
      bmp.Save(targetFilePath, targetFormat); 
     } 
     return fType; 
    } 

    /// <summary> 
    /// Rotate the given bitmap according to Exif Orientation data 
    /// </summary> 
    /// <param name="img">source image</param> 
    /// <param name="updateExifData">set it to TRUE to update image Exif data after rotation (default is TRUE)</param> 
    /// <returns>The RotateFlipType value corresponding to the applied rotation. If no rotation occurred, RotateFlipType.RotateNoneFlipNone will be returned.</returns> 
    public static RotateFlipType RotateImageByExifOrientationData(Image img, bool updateExifData = true) 
    { 
     int orientationId = 0x0112; 
     var fType = RotateFlipType.RotateNoneFlipNone; 
     if (img.PropertyIdList.Contains(orientationId)) 
     { 
      var pItem = img.GetPropertyItem(orientationId); 
      fType = GetRotateFlipTypeByExifOrientationData(pItem.Value[0]); 
      if (fType != RotateFlipType.RotateNoneFlipNone) 
      { 
       img.RotateFlip(fType); 
       // Remove Exif orientation tag (if requested) 
       if (updateExifData) img.RemovePropertyItem(orientationId); 
      } 
     } 
     return fType; 
    } 

    /// <summary> 
    /// Return the proper System.Drawing.RotateFlipType according to given orientation EXIF metadata 
    /// </summary> 
    /// <param name="orientation">Exif "Orientation"</param> 
    /// <returns>the corresponding System.Drawing.RotateFlipType enum value</returns> 
    public static RotateFlipType GetRotateFlipTypeByExifOrientationData(int orientation) 
    { 
     switch (orientation) 
     { 
      case 1: 
      default: 
       return RotateFlipType.RotateNoneFlipNone; 
      case 2: 
       return RotateFlipType.RotateNoneFlipX; 
      case 3: 
       return RotateFlipType.Rotate180FlipNone; 
      case 4: 
       return RotateFlipType.Rotate180FlipX; 
      case 5: 
       return RotateFlipType.Rotate90FlipX; 
      case 6: 
       return RotateFlipType.Rotate90FlipNone; 
      case 7: 
       return RotateFlipType.Rotate270FlipX; 
      case 8: 
       return RotateFlipType.Rotate270FlipNone; 
     } 
    } 
}