获得正确的图像旋转 [英] Getting correct Image rotation
问题描述
我有一个简单的问题：当我将图像加载到Windows窗体 PictureBox 时，某些图片会被旋转，而其他图片则不会。
I have a simple problem: When I load an image to a windows form PictureBox some pictures are rotated and others are not.
基本上，用户选择带有 OpenFileDialog 的图片，并且当选择图片时：
Basically, a user selects a picture with an OpenFileDialog and when the picture is selected:
private void OpenFD_FileOk(object sender, CancelEventArgs e)
{
Image image = Image.FromFile(openFD.FileName);
PB_profile.Image = image;
}
是的，我检查了原始图像轮换
And yes I checked the original image rotation
编辑：
我将 PictureBox 属性 SizeMode 更改为 StretchImage
推荐答案
如果图片包含< a href =https://msdn.microsoft.com/en-us/library/ms534416.aspx?f=255&MSPPError=-2147217396 =nofollow noreferrer> exif data PropertyItems 应包含方向标记。
它对正确显示图像所需的旋转/翻转进行编码：
It encodes the rotation/flipping necessary to display the image correctly:
PropertyTagOrientation
PropertyTagOrientation
按行和列查看图像方向。
Image orientation viewed in terms of rows and columns.
标签0x0112
1 - 第0行位于
可视图像的顶部，第0列是视觉左侧。
2 - 第0个
行位于图像的可视顶部，第0列是
可视右侧。 br>
3 - 第0行位于
图像的可视底部，第0列是可视右侧。
4 - 第0行
在图像的视觉底部，第0列是视觉
左侧。
5 - 第0行是图像的视觉左侧，
第0列是视觉顶部。
6 - 第0行是图像的右侧
侧，第0列是视觉顶部。
7 - 第0行
行是图像的视觉右侧，第0列是
视觉底部。
8 - 第0行是图像的视觉左侧，
和第0列是视觉底部。
1 - The 0th row is at the top of the
visual image, and the 0th column is the visual left side.
2 - The 0th
row is at the visual top of the image, and the 0th column is the
visual right side.
3 - The 0th row is at the visual bottom of the
image, and the 0th column is the visual right side.
4 - The 0th row
is at the visual bottom of the image, and the 0th column is the visual
left side.
5 - The 0th row is the visual left side of the image, and
the 0th column is the visual top.
6 - The 0th row is the visual right
side of the image, and the 0th column is the visual top.
7 - The 0th
row is the visual right side of the image, and the 0th column is the
visual bottom.
8 - The 0th row is the visual left side of the image,
and the 0th column is the visual bottom.
这是一个检索 PropertyItem的函数：
PropertyItem getPropertyItemByID(Image img, int Id)
{
return img.PropertyItems.Select(x => x).FirstOrDefault(x => x.Id == Id);
}
以下是使用GDI + RotateFlip <的示例/ code>动态调整图像的方法：
Here is an example of using the GDI+ RotateFlip method to adjust an image on the fly:
void Rotate(Bitmap bmp)
{
PropertyItem pi = bmp.PropertyItems.Select(x => x)
.FirstOrDefault(x => x.Id == 0x0112);
if (pi == null) return;
byte o = pi.Value[0];
if (o==2) bmp.RotateFlip(RotateFlipType.RotateNoneFlipX);
if (o==3) bmp.RotateFlip(RotateFlipType.RotateNoneFlipXY);
if (o==4) bmp.RotateFlip(RotateFlipType.RotateNoneFlipY);
if (o==5) bmp.RotateFlip(RotateFlipType.Rotate90FlipX);
if (o==6) bmp.RotateFlip(RotateFlipType.Rotate90FlipNone);
if (o==7) bmp.RotateFlip(RotateFlipType.Rotate90FlipY);
if (o==8) bmp.RotateFlip(RotateFlipType.Rotate90FlipXY);
}
它返回旋转版本..
我已用这套漂亮的样本图片。
注意：代码仅在图像实际包含方向标记时才有效。如果他们不这样做，也许是因为他们是扫描，那么它将没有。
Note: The code will only work if the images actually contain the orientation tag. If they don't, maybe because they are scans, then it will do nothing.
注意2 你写了我检查了原始图像旋转。这不是那么简单：资源管理器将显示已旋转的图像，所以在这里它们都看起来正确，甚至检查属性也不会显示方向！
Note 2 You wrote I checked the original image rotation. This is not so simple: The explorer will display the images already rotated, so here they all look right and even inspecting the properties doesn't reveal the orientation!
通常，当没有exif数据时， PropertyTagOrientation 标记 存在，但只有默认值 1 ..
Usually, when no exif data are present, the PropertyTagOrientation tag is present but only has the default value of 1..
更新：
如果图片没有拥有 PropertyTagOrientation 以下是如何添加一个：
Update:
If the image doesn't have the PropertyTagOrientation here is how you can add one:
using System.Runtime.Serialization;
..
pi = (PropertyItem)FormatterServices
.GetUninitializedObject(typeof(PropertyItem));
pi.Id = 0x0112; // orientation
pi.Len = 2;
pi.Type = 3;
pi.Value = new byte[2] { 1, 0 };
pi.Value[0] = yourOrientationByte;
yourImage.SetPropertyItem(pi);
感谢@ ne1410s出色的在这里回答！。
Kudos to @ne1410s's excellent answer here!.
注意添加图像的 PropertyItems 不会添加exif数据;这两个是不同的标签集！
Note that adding PropertyItems to an image does not add exif data; the two are different tag sets!
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