我正在尝试调整并保存一张图片,这很容易实现(例如,参见此示例)。但是,使用此代码会从图像中剥离元数据信息。我似乎无法弄清楚如何保留jpeg图像的元数据。
编辑:示例代码
编辑:示例代码
public static void ResizeMethodThree(string sourceFile, string targetFile)
{
byte[] baSource = File.ReadAllBytes(sourceFile);
PropertyItem[] propertyItems = new Bitmap(sourceFile).PropertyItems;
using (Stream streamPhoto = new MemoryStream(baSource))
{
BitmapFrame bfPhoto = ReadBitmapFrame(streamPhoto);
BitmapMetadata metaData = (BitmapMetadata)bfPhoto.Metadata;
int nNewPictureSize = 200;
int nWidth = 0;
int nHeight = 0;
if (bfPhoto.Width > bfPhoto.Height)
{
nWidth = nNewPictureSize;
nHeight = (int)(bfPhoto.Height * nNewPictureSize / bfPhoto.Width);
}
else
{
nHeight = nNewPictureSize;
nWidth = (int)(bfPhoto.Width * nNewPictureSize / bfPhoto.Height);
}
BitmapFrame bfResize = ResizeHelper(bfPhoto, nWidth, nHeight, BitmapScalingMode.HighQuality);
byte[] baResize = ToByteArray(bfResize);
File.WriteAllBytes(targetFile, baResize);
Image targetImage = new Bitmap(targetFile);
foreach (var propertyItem in propertyItems)
{
targetImage.SetPropertyItem(propertyItem);
}
targetImage.Save(targetFile);
}
}
public static BitmapFrame ResizeHelper(BitmapFrame photo, int width,
int height, BitmapScalingMode scalingMode)
{
var group = new DrawingGroup();
RenderOptions.SetBitmapScalingMode(
group, scalingMode);
group.Children.Add(
new ImageDrawing(photo,
new Rect(0, 0, width, height)));
var targetVisual = new DrawingVisual();
var targetContext = targetVisual.RenderOpen();
targetContext.DrawDrawing(group);
var target = new RenderTargetBitmap(
width, height, 96, 96, PixelFormats.Default);
targetContext.Close();
target.Render(targetVisual);
var targetFrame = BitmapFrame.Create(target);
return targetFrame;
}
private static byte[] ToByteArray(BitmapFrame bfResize)
{
using (MemoryStream msStream = new MemoryStream())
{
JpegBitmapEncoder jpgEncoder = new JpegBitmapEncoder();
jpgEncoder.Frames.Add(bfResize);
jpgEncoder.Save(msStream);
return msStream.ToArray();
}
}
private static BitmapFrame ReadBitmapFrame(Stream streamPhoto)
{
BitmapDecoder bdDecoder =
BitmapDecoder.Create(streamPhoto, BitmapCreateOptions.PreservePixelFormat, BitmapCacheOption.None);
return bdDecoder.Frames[0];
}