C# 如何使用C向JPEG文件添加“注释”
在JPEG图像的属性窗口中，有一个名为“摘要”的选项卡。在这个选项卡中，有一个名为“Comments”的字段，我想写一些c代码，它将向这个字段添加一个给定的字符串，例如这是一张照片 有什么善良的灵魂知道怎么做吗 非常感谢。简单的部分： 添加此属性项：C# 如何使用C向JPEG文件添加“注释”,c#,metadata,jpeg,C#,Metadata,Jpeg,在JPEG图像的属性窗口中，有一个名为“摘要”的选项卡。在这个选项卡中，有一个名为“Comments”的字段，我想写一些c代码，它将向这个字段添加一个给定的字符串，例如这是一张照片 有什么善良的灵魂知道怎么做吗 非常感谢。简单的部分： 添加此属性项： var data = System.Text.Encoding.UTF8.GetBytes( "Some comments" ); PropertyItem pi; *** create an empty PropertyItem here pi.
var data = System.Text.Encoding.UTF8.GetBytes( "Some comments" );
PropertyItem pi;
*** create an empty PropertyItem here
pi.Type = 2;
pi.Id = 37510;
pi.Len = data.Length;
pi.Value = data;
常见的技巧是有一个空的图像，你可以从中窃取一个PropertyItem。叹息以下代码解决了我的问题，并向给定的JPEG图像添加注释：
public void addImageComment(string imageFlePath, string comments)
{
string jpegDirectory = Path.GetDirectoryName(imageFlePath);
string jpegFileName = Path.GetFileNameWithoutExtension(imageFlePath);
BitmapDecoder decoder = null;
BitmapFrame bitmapFrame = null;
BitmapMetadata metadata = null;
FileInfo originalImage = new FileInfo(imageFlePath);
if (File.Exists(imageFlePath))
{
// load the jpg file with a JpegBitmapDecoder
using (Stream jpegStreamIn = File.Open(imageFlePath, FileMode.Open, FileAccess.ReadWrite, FileShare.None))
{
decoder = new JpegBitmapDecoder(jpegStreamIn, BitmapCreateOptions.PreservePixelFormat, BitmapCacheOption.OnLoad);
}
bitmapFrame = decoder.Frames[0];
metadata = (BitmapMetadata)bitmapFrame.Metadata;
if (bitmapFrame != null)
{
BitmapMetadata metaData = (BitmapMetadata)bitmapFrame.Metadata.Clone();
if (metaData != null)
{
// modify the metadata
metaData.SetQuery("/app1/ifd/exif:{uint=40092}", comments);
// get an encoder to create a new jpg file with the new metadata.
JpegBitmapEncoder encoder = new JpegBitmapEncoder();
encoder.Frames.Add(BitmapFrame.Create(bitmapFrame, bitmapFrame.Thumbnail, metaData, bitmapFrame.ColorContexts));
//string jpegNewFileName = Path.Combine(jpegDirectory, "JpegTemp.jpg");
// Delete the original
originalImage.Delete();
// Save the new image
using (Stream jpegStreamOut = File.Open(imageFlePath, FileMode.CreateNew, FileAccess.ReadWrite))
{
encoder.Save(jpegStreamOut);
}
}
}
}
}
非常感谢danbystrom和Konamiman在这件事上的帮助。我真的很感谢您的快速回复。多亏了前面的提示，我才能够将以下内容组合在一起。我已经测试过了，它似乎有效。最大的障碍之一是确定要分配的字段所需的Id
string fileName = "c:/SomeImage.jpg";
// Retrieve the Image
System.Drawing.Image originalImage = System.Drawing.Image.FromFile(fileName);
// Get the list of existing PropertyItems. i.e. the metadata
PropertyItem[] properties = originalImage.PropertyItems;
// Create a bitmap image to assign attributes and do whatever else..
Bitmap bmpImage = new Bitmap((Bitmap)originalImage);
// Don't need this anymore
originalImage.Dispose();
// Get / setup a PropertyItem
PropertyItem item = properties[0]; // We have to copy an existing one since no constructor exists
// This will assign "Joe Doe" to the "Authors" metadata field
string sTmp = "Joe DoeX"; // The X will be replaced with a null. String must be null terminated.
var itemData = System.Text.Encoding.UTF8.GetBytes(sTmp);
itemData[itemData.Length - 1] = 0;// Strings must be null terminated or they will run together
item.Type = 2; //String (ASCII)
item.Id = 315; // Author(s), 315 is mapped to the "Authors" field
item.Len = itemData.Length; // Number of items in the byte array
item.Value = itemData; // The byte array
bmpImage.SetPropertyItem(item); // Assign / add to the bitmap
// This will assign "MyApplication" to the "Program Name" field
sTmp = "MyApplicationX";
itemData = System.Text.Encoding.UTF8.GetBytes(sTmp);
itemData[itemData.Length - 1] = 0; // Strings must be null terminated or they will run together
item.Type = 2; //String (ASCII)
item.Id = 305; // Program Name, 305 is mapped to the "Program Name" field
item.Len = itemData.Length;
item.Value = itemData;
bmpImage.SetPropertyItem(item);
// Save the image
bmpImage.Save(fileName, System.Drawing.Imaging.ImageFormat.Jpeg);
//Clean up
bmpImage.Dispose();
多亏了这里的答案，我编写了一个解决方案，只使用内存设置注释：
public static Image SetImageComment(Image image, string comment) {
using (var memStream = new MemoryStream()) {
image.Save(memStream, ImageFormat.Jpeg);
memStream.Position = 0;
var decoder = new JpegBitmapDecoder(memStream, BitmapCreateOptions.PreservePixelFormat, BitmapCacheOption.OnLoad);
BitmapMetadata metadata;
if (decoder.Metadata == null) {
metadata = new BitmapMetadata("jpg");
} else {
metadata = decoder.Metadata;
}
metadata.Comment = comment;
var bitmapFrame = decoder.Frames[0];
BitmapEncoder encoder = new JpegBitmapEncoder();
encoder.Frames.Add(BitmapFrame.Create(bitmapFrame, bitmapFrame.Thumbnail, metadata, bitmapFrame.ColorContexts));
var imageStream = new MemoryStream();
encoder.Save(imageStream);
imageStream.Position = 0;
image.Dispose();
image = null;
return Image.FromStream(imageStream);
}
}
不要忘记处理此方法返回的映像。例如，在根据其他答案将图像保存到文件后，我编写了以下类，该类允许各种元数据操作。您可以这样使用它：
var jpeg = new JpegMetadataAdapter(pathToJpeg);
jpeg.Metadata.Comment = "Some comments";
jpeg.Metadata.Title = "A title";
jpeg.Save(); // Saves the jpeg in-place
jpeg.SaveAs(someNewPath); // Saves with a new path
Peter Kistler解决方案的变体，用于设置标题、主题和评论。我发现我必须将项目创建为Unicode字节数组类型1，标题、主题和注释的ID与EXIF XPTitle、XPSubject和XP Comment的ID相同。sFileOut可以与sFile相同
public static void SetWindowsTags2(string sFile, string sFileOut, string Title = "", string Subject = "", string Comment = "", bool bShowError = false)
{
try
{
// Retrieve the Image
System.Drawing.Image originalImage = System.Drawing.Image.FromFile(sFile);
// Get the list of existing PropertyItems. i.e. the metadata
PropertyItem[] properties = originalImage.PropertyItems;
/*foreach (PropertyItem propItem in properties)
{
string sTag = System.Text.Encoding.UTF8.GetString(propItem.Value);
string sItem = sTag.Replace("\0", string.Empty);
Debug.Print(propItem.Id.ToString() + ", " + propItem.Type + ", " + sItem);
}*/
// Create a bitmap image to assign attributes and do whatever else..
Bitmap bmpImage = new Bitmap((Bitmap)originalImage);
// Don't need this anymore
originalImage.Dispose();
// Get / setup a PropertyItem
PropertyItem item = properties[0]; // We have to copy an existing one since no constructor exists
var itemData = System.Text.Encoding.Unicode.GetBytes(Title);
itemData[itemData.Length - 1] = 0;// Strings must be null terminated or they will run together
item.Type = 1; //Unicode Byte Array
item.Id = 40091; // Title ID
item.Len = itemData.Length; // Number of items in the byte array
item.Value = itemData; // The byte array
bmpImage.SetPropertyItem(item); // Assign / add to the bitmap
itemData = System.Text.Encoding.Unicode.GetBytes(Subject);
itemData[itemData.Length - 1] = 0; // Strings must be null terminated or they will run together
item.Type = 1; //Unicode Byte Array
item.Id = 40095; // subject
item.Len = itemData.Length;
item.Value = itemData;
bmpImage.SetPropertyItem(item); // Assign / add to the bitmap
itemData = System.Text.Encoding.Unicode.GetBytes(Comment);
itemData[itemData.Length - 1] = 0; // Strings must be null terminated or they will run together
item.Type = 1; ////Unicode Byte Array
item.Id = 40092; // comment
item.Len = itemData.Length;
item.Value = itemData;
bmpImage.SetPropertyItem(item); // Assign / add to the bitmap
// Save the image
bmpImage.Save(sFileOut, System.Drawing.Imaging.ImageFormat.Jpeg);
//Clean up
bmpImage.Dispose();
}
catch (Exception Ex)
{
}
}
你如何将被盗财产项目与真实图像联系起来？是否为读写属性/变量？realImage.PropertyItems.Add emptyImage.PropertyItems[0]；令人沮丧的。来自msdn:PropertyItem不打算用作独立对象。PropertyItem对象用于从Image派生的类。PropertyItem对象用于检索和更改现有图像文件的元数据，而不是创建元数据。因此，PropertyItem类没有定义的公共构造函数，并且您无法创建PropertyItem对象的实例。此答案为如何创建PropertyItem的新实例提供了解决方案：如果您觉得他们的答案有用，您应该投票赞成和/或接受他们的答案。干杯哎呀，我在上面的解决方案中犯了一个小错误。我应该说你需要添加PresentationCore参考，而不是系统。核心Ps。谢谢你的提醒！我会马上这么做。鉴于jpeg是一种有损格式，您是否希望通过使用此方法添加元数据来降低质量，或者这只是在不影响图片的情况下修改元数据？这太棒了，正是我所需要的干净有序的方式。非常感谢你！使用System.Windows.Media.ImagingI也需要对System.Xaml进行引用。我知道这很旧，但对其他类型的文件（如Office文档、文本文件、PDF等）也可以这样做吗？
public static void SetWindowsTags2(string sFile, string sFileOut, string Title = "", string Subject = "", string Comment = "", bool bShowError = false)
{
try
{
// Retrieve the Image
System.Drawing.Image originalImage = System.Drawing.Image.FromFile(sFile);
// Get the list of existing PropertyItems. i.e. the metadata
PropertyItem[] properties = originalImage.PropertyItems;
/*foreach (PropertyItem propItem in properties)
{
string sTag = System.Text.Encoding.UTF8.GetString(propItem.Value);
string sItem = sTag.Replace("\0", string.Empty);
Debug.Print(propItem.Id.ToString() + ", " + propItem.Type + ", " + sItem);
}*/
// Create a bitmap image to assign attributes and do whatever else..
Bitmap bmpImage = new Bitmap((Bitmap)originalImage);
// Don't need this anymore
originalImage.Dispose();
// Get / setup a PropertyItem
PropertyItem item = properties[0]; // We have to copy an existing one since no constructor exists
var itemData = System.Text.Encoding.Unicode.GetBytes(Title);
itemData[itemData.Length - 1] = 0;// Strings must be null terminated or they will run together
item.Type = 1; //Unicode Byte Array
item.Id = 40091; // Title ID
item.Len = itemData.Length; // Number of items in the byte array
item.Value = itemData; // The byte array
bmpImage.SetPropertyItem(item); // Assign / add to the bitmap
itemData = System.Text.Encoding.Unicode.GetBytes(Subject);
itemData[itemData.Length - 1] = 0; // Strings must be null terminated or they will run together
item.Type = 1; //Unicode Byte Array
item.Id = 40095; // subject
item.Len = itemData.Length;
item.Value = itemData;
bmpImage.SetPropertyItem(item); // Assign / add to the bitmap
itemData = System.Text.Encoding.Unicode.GetBytes(Comment);
itemData[itemData.Length - 1] = 0; // Strings must be null terminated or they will run together
item.Type = 1; ////Unicode Byte Array
item.Id = 40092; // comment
item.Len = itemData.Length;
item.Value = itemData;
bmpImage.SetPropertyItem(item); // Assign / add to the bitmap
// Save the image
bmpImage.Save(sFileOut, System.Drawing.Imaging.ImageFormat.Jpeg);
//Clean up
bmpImage.Dispose();
}
catch (Exception Ex)
{
}
}