PropertyItems
代码
/// <summary>/// 根据图片exif调整方向/// </summary>/// <param name="img"></param>public void RotateImage(Bitmap img){var exif = img.PropertyItems;byte orien = 0;var item = exif.Where(m => m.Id == 274).ToArray();if (item.Length > 0)orien = item[0].Value[0];switch (orien){case 2:img.RotateFlip(RotateFlipType.RotateNoneFlipX);//horizontal flipbreak;case 3:img.RotateFlip(RotateFlipType.Rotate180FlipNone);//right-topbreak;case 4:img.RotateFlip(RotateFlipType.RotateNoneFlipY);//vertical flipbreak;case 5:img.RotateFlip(RotateFlipType.Rotate90FlipX);break;case 6:img.RotateFlip(RotateFlipType.Rotate90FlipNone);//right-topbreak;case 7:img.RotateFlip(RotateFlipType.Rotate270FlipX);break;case 8:img.RotateFlip(RotateFlipType.Rotate270FlipNone);//left-bottombreak;default:break;}}
什么是 EXIF
Exif是英文Exchangeable Image File(可交换图像文件)的缩写,最初由日本电子工业发展协会(JEIDA --Japan Electronic Industry Development Association) 制订,目前的最新版本是发表于2002年04月的2.21 版。国际标准化组织(ISO)正在制订的相机文件设计标准(DCF -- Design role for Camera File system)可能以Exif2.1为基础。
Exif 文件实际是JPEG文件的一种,遵从JPEG标准,只是在文件头信息中增加了有关拍摄信息的内容和索引图。所以你可以使用任何支持JPEG格式的图像工具软件观看或修改Exif文件,但,打开时可能看不到Exif信息,一旦修改,Exif信息可能丢失。
所有的JPEG文件以字符串“0xFFD8”开头,并以字符串“0xFFD9”结束。文件头中有一系列“0xFF??”格式的字符串,称为“标识”,用来标记JPEG文件的信息段。“0xFFD8”表示图像信息开始,“0xFFD9”表示图像信息结束,这两个标识后面没有信息,而其它标识紧跟一些信息字符。
0xFFE0 -- 0xFFEF之间的标识符称为“应用标记”,没有被常规JPEG文件利用,Exif正是利用这些信息串记录拍摄信息如快门速度、光圈值等,甚至可以包括全球定位信息。其中拍摄方向的ID为“0x0112”,有1至8共8种值。
EXIF Orientation
Orientation
The image orientation viewed in terms of rows and columns.
Tag = 274 (112.H)
Type = SHORT
Count = 1
Default = 1
1 = The 0th row is at the visual top of the image, and the 0th column is the visual left-hand side.
2 = The 0th row is at the visual top of the image, and the 0th column is the visual right-hand side.
3 = The 0th row is at the visual bottom of the image, and the 0th column is the visual right-hand side.
4 = The 0th row is at the visual bottom of the image, and the 0th column is the visual left-hand side.
5 = The 0th row is the visual left-hand side of the image, and the 0th column is the visual top.
6 = The 0th row is the visual right-hand side of the image, and the 0th column is the visual top.
7 = The 0th row is the visual right-hand side of the image, and the 0th column is the visual bottom.
8 = The 0th row is the visual left-hand side of the image, and the 0th column is the visual bottom.
Other = reserved