我怎么知道我从stream中获取的图像格式？
我从一些Web服务获得一个字节stream。 这个字节stream包含图像的二进制date，我使用下面的方法将其转换为一个Image实例。
我需要知道我有什么样的形象。 它是一个简单的位图（ *.bmp ）或JPEG图像（ *.jpg ）或PNG图像？
我怎样才能find它？
public static Image byteArrayToImage( byte[] bmpBytes ) { Image image = null; using( MemoryStream stream = new MemoryStream( bmpBytes ) ) { image = Image.FromStream( stream ); } return image; }
您可以检出Image.RawFormat属性。 所以一旦你从stream中加载你可以testing的图像：
if (ImageFormat.Jpeg.Equals(image.RawFormat)) { // JPEG } else if (ImageFormat.Png.Equals(image.RawFormat)) { // PNG } else if (ImageFormat.Gif.Equals(image.RawFormat)) { // GIF } ... etc
在C＃中，我们可以使用Image.RawFormat来检查Image的ImageFormat。 但是RawFormat属性在Compact Framework中似乎不可用。 所以我认为你必须使用Imaging API。 有很多types需要。 在这里，我正在给你一个例子，我认为它会帮助你一些什么。
using System; using System.Drawing; using System.IO; using System.Runtime.InteropServices; /// <summary> /// This structure contains parameters related to an image. /// </summary> [StructLayout(LayoutKind.Sequential)] internal struct ImageInfo { #region Fields /// <summary> /// A GUID value that identifies the file format for the native image data. This value is an image format identifier. For more information, see Imaging GUIDs. /// </summary> public Guid RawDataFormat; public PixelFormatID PixelFormat; public uint Width; public uint Height; public uint TileWidth; public uint TileHeight; public double Xdpi; public double Ydpi; public SinkFlags Flags; #endregion } [StructLayout(LayoutKind.Sequential)] public struct FILETIME { #region Fields public int dwLowDateTime; public int dwHighDateTime; #endregion } [StructLayout(LayoutKind.Sequential)] internal struct BitmapData { #region Fields public int Width; public int Height; public int Stride; public PixelFormatID PixelFormat; public IntPtr Scan0; public IntPtr Reserved; #endregion } [StructLayout(LayoutKind.Sequential, CharSet = CharSet.Unicode)] public struct STATSTG { #region Fields [MarshalAs(UnmanagedType.LPWStr)] public string pwcsName; public int type; public long cbSize; public FILETIME mtime; public FILETIME ctime; public FILETIME atime; public int grfMode; public int grfLocksSupported; public Guid clsid; public int grfStateBits; public int reserved; #endregion } /// <summary> /// COM IStream interface /// </summary> [ComImport] [Guid("0000000c-0000-0000-C000-000000000046")] [InterfaceType(ComInterfaceType.InterfaceIsIUnknown)] public interface IStream { void Read([Out, MarshalAs(UnmanagedType.LPArray, SizeParamIndex = 1)] byte[] pv, int cb, IntPtr pcbRead); void Write([MarshalAs(UnmanagedType.LPArray, SizeParamIndex = 1)] byte[] pv, int cb, IntPtr pcbWritten); void Seek(long dlibMove, int origin, IntPtr plibNewPosition); void SetSize(long libNewSize); void CopyTo(IStream pstm, long cb, IntPtr pcbRead, IntPtr pcbWritten); void Commit(int grfCommitFlags); void Revert(); void LockRegion(long libOffset, long cb, int lockType); void UnlockRegion(long libOffset, long cb, int lockType); void Stat(out STATSTG pstatstg, int grfStatFlag); void Clone(out IStream ppstm); } /// <summary> /// Pulled from imaging.h in the Windows Mobile 5.0 Pocket PC SDK /// </summary> [ComImport] [Guid("327ABDAA-072B-11D3-9D7B-0000F81EF32E")] [InterfaceType(ComInterfaceType.InterfaceIsIUnknown)] [ComVisible(true)] internal interface IBitmapImage { uint GetSize(out Size size); uint GetPixelFormatID(out PixelFormatID pixelFormat); uint LockBits(ref RECT rect, uint flags, PixelFormatID pixelFormat, ref BitmapData lockedBitmapData); uint UnlockBits(ref BitmapData lockedBitmapData); uint GetPalette(); // This is a place holder uint SetPalette(); // This is a place holder } /// <summary> /// Pulled from imaging.h in the Windows Mobile 5.0 Pocket PC SDK /// </summary> [ComImport] [Guid("327ABDA7-072B-11D3-9D7B-0000F81EF32E")] [InterfaceType(ComInterfaceType.InterfaceIsIUnknown)] [ComVisible(true)] internal interface IImagingFactory { uint CreateImageFromStream(IStream stream, out IImage image); uint CreateImageFromFile(string filename, out IImage image); // We need the MarshalAs attribute here to keep COM interop from sending the buffer down as a Safe Array. // uint CreateImageFromBuffer([MarshalAs(UnmanagedType.LPArray)] byte[] buffer, uint size, BufferDisposalFlag disposalFlag, out IImage image); uint CreateImageFromBuffer(IntPtr buffer, uint size, BufferDisposalFlag disposalFlag, out IImage image); uint CreateNewBitmap(); // This is a place holder uint CreateBitmapFromImage(IImage image, uint width, uint height, PixelFormatID pixelFormat, InterpolationHint hints, out IBitmapImage bitmap); // This is a place holder uint CreateBitmapFromBuffer(); // This is a place holder uint CreateImageDecoder(); // This is a place holder uint CreateImageEncoderToStream(); // This is a place holder uint CreateImageEncoderToFile(ref Guid clsid, string filename, out IImageEncoder encoder); uint GetInstalledDecoders([Out] out uint size, [Out] out IntPtr decoders); uint GetInstalledEncoders([Out] out uint size, [Out] out IntPtr ecoders); uint InstallImageCodec(); // This is a place holder uint UninstallImageCodec(); // This is a place holder } /// <summary> /// Pulled from imaging.h in the Windows Mobile 5.0 Pocket PC SDK /// </summary> [ComImport] [Guid("327ABDAC-072B-11D3-9D7B-0000F81EF32E")] [InterfaceType(ComInterfaceType.InterfaceIsIUnknown)] internal interface IImageEncoder { int InitEncoder(IStream stream); int TerminateEncoder(); int GetEncodeSink(); int SetFrameDimension(ref Guid dimensionID); int GetEncoderParameterListSize(out uint size); int GetEncoderParameterList(uint size, out IntPtr @params); int SetEncoderParameters(IntPtr param); } /// <summary> /// This structure defines the coordinates of the upper-left and lower-right corners of a rectangle. /// </summary> [StructLayout(LayoutKind.Sequential)] internal struct RECT { #region Fields public int left; public int top; public int right; public int bottom; #endregion } // Pulled from imaging.h in the Windows Mobile 5.0 Pocket PC SDK internal enum BufferDisposalFlag : int { BufferDisposalFlagNone, BufferDisposalFlagGlobalFree, BufferDisposalFlagCoTaskMemFree, BufferDisposalFlagUnmapView } // Pulled from imaging.h in the Windows Mobile 5.0 Pocket PC SDK internal enum InterpolationHint : int { InterpolationHintDefault, InterpolationHintNearestNeighbor, InterpolationHintBilinear, InterpolationHintAveraging, InterpolationHintBicubic } /// <summary> /// These values are flags used to identify the numerical formats of pixels in images. /// </summary> [Flags] public enum PixelFormatID { PixelFormatIndexed = 0x00010000, PixelFormatGDI = 0x00020000, PixelFormatAlpha = 0x00040000, PixelFormatPAlpha = 0x00080000, PixelFormatExtended = 0x00100000, PixelFormatCanonical = 0x00200000, PixelFormatUndefined = 0, PixelFormat1bppIndexed = (1 | (1 << 8) | PixelFormatIndexed | PixelFormatGDI), PixelFormat4bppIndexed = (2 | (4 << 8) | PixelFormatIndexed | PixelFormatGDI), PixelFormat16bppGrayScale = (4 | (16 << 8) | PixelFormatExtended), PixelFormat8bppIndexed = (3 | (8 << 8) | PixelFormatIndexed | PixelFormatGDI), PixelFormat16bppRGB555 = (5 | (16 << 8) | PixelFormatGDI), PixelFormat16bppRGB565 = (6 | (16 << 8) | PixelFormatGDI), PixelFormat16bppARGB1555 = (7 | (16 << 8) | PixelFormatAlpha | PixelFormatGDI), PixelFormat24bppRGB = (8 | (24 << 8) | PixelFormatGDI), PixelFormat32bppRGB = (9 | (32 << 8) | PixelFormatGDI), PixelFormat32bppARGB = (10 | (32 << 8) | PixelFormatAlpha | PixelFormatGDI | PixelFormatCanonical), PixelFormat32bppPARGB = (11 | (32 << 8) | PixelFormatAlpha | PixelFormatPAlpha | PixelFormatGDI), PixelFormat48bppRGB = (12 | (48 << 8) | PixelFormatExtended), PixelFormat64bppARGB = (13 | (64 << 8) | PixelFormatAlpha | PixelFormatCanonical | PixelFormatExtended), PixelFormat64bppPARGB = (14 | (64 << 8) | PixelFormatAlpha | PixelFormatPAlpha | PixelFormatExtended), PixelFormatMax = 15 } [Flags] internal enum SinkFlags : uint { // Low-word: shared with ImgFlagx Scalable = 0x0001, HasAlpha = 0x0002, HasTranslucent = 0x0004, PartiallyScalable = 0x0008, ColorSpaceRGB = 0x0010, ColorSpaceCMYK = 0x0020, ColorSpaceGRAY = 0x0040, ColorSpaceYCBCR = 0x0080, ColorSpaceYCCK = 0x0100, // Low-word: image size info HasRealDPI = 0x1000, HasRealPixelSize = 0x2000, // High-word TopDown = 0x00010000, BottomUp = 0x00020000, FullWidth = 0x00040000, Multipass = 0x00080000, Composite = 0x00100000, WantProps = 0x00200000 } /// <summary> /// Pulled from imaging.h in the Windows Mobile 5.0 Pocket PC SDK /// </summary> [ComImport] [Guid("327ABDA9-072B-11D3-9D7B-0000F81EF32E")] [InterfaceType(ComInterfaceType.InterfaceIsIUnknown)] [ComVisible(true)] internal interface IImage { uint GetPhysicalDimension(out Size size); uint GetImageInfo(ref ImageInfo info); uint SetImageFlags(uint flags); // "Correct" declaration: uint Draw(IntPtr hdc, ref Rectangle dstRect, ref Rectangle srcRect); uint Draw(IntPtr hdc, ref RECT dstRect, IntPtr srcRect); uint PushIntoSink(); // This is a place holder uint GetThumbnail(uint thumbWidth, uint thumbHeight, out IImage thumbImage); } /// <summary> /// Implmentation for the COM IStream interface /// </summary> public sealed class StreamOnFile : IStream, IDisposable { #region Fields private readonly Stream stream; private readonly string fileName; #endregion #region Constructors /// <summary> /// Initializes a new instance of the <see cref="StreamOnFile"/> class. /// </summary> /// <param name="fileName">File name to open /// </param> internal StreamOnFile(string fileName) { this.fileName = fileName; // prevent another processes/threads (mainly delete from web) from using this file while Imaging API is trying to access it this.stream = new FileStream(fileName, FileMode.Open, FileAccess.Read, FileShare.None); } #endregion #region Properties /// <summary> /// Gets the file name /// </summary> public string FileName { get { return this.fileName; } } #endregion #region Methods public void Read(byte[] pv, int cb, IntPtr pcbRead) { int val = this.stream.Read(pv, 0, cb); if (pcbRead != IntPtr.Zero) { Marshal.WriteInt32(pcbRead, val); } } public void Write(byte[] pv, int cb, IntPtr pcbWritten) { this.stream.Write(pv, 0, cb); if (pcbWritten != IntPtr.Zero) { Marshal.WriteInt32(pcbWritten, cb); } } public void Seek(long dlibMove, int origin, IntPtr plibNewPosition) { long val = this.stream.Seek(dlibMove, (SeekOrigin)origin); if (plibNewPosition != IntPtr.Zero) { Marshal.WriteInt64(plibNewPosition, val); } } public void SetSize(long libNewSize) { throw new NotImplementedException("The method or operation is not implemented."); } public void CopyTo(IStream pstm, long cb, IntPtr pcbRead, IntPtr pcbWritten) { throw new NotImplementedException("The method or operation is not implemented."); } public void Commit(int grfCommitFlags) { throw new NotImplementedException("The method or operation is not implemented."); } public void Revert() { throw new NotImplementedException("The method or operation is not implemented."); } public void LockRegion(long libOffset, long cb, int lockType) { throw new NotImplementedException("The method or operation is not implemented."); } public void UnlockRegion(long libOffset, long cb, int lockType) { throw new NotImplementedException("The method or operation is not implemented."); } public void Stat(out STATSTG pstatstg, int grfStatFlag) { throw new NotImplementedException("The method or operation is not implemented."); } public void Clone(out IStream ppstm) { throw new NotImplementedException("The method or operation is not implemented."); } public void Dispose() { if (this.stream != null) { this.stream.Close(); } } #endregion } public enum ImageType { Undefined, MemoryBMP, BMP, EMF, WMF, JPEG, PNG, GIF, TIFF, EXIF, Icon } public static class BitmapProperties { /// <summary> /// Indicates the Microsoft Windowsbitmap (BMP) format. /// </summary> private static readonly Guid ImageFormatBMP = new Guid("B96B3CAB-0728-11D3-9D7B-0000F81EF32E"); /// <summary> /// Indicates the Enhanced Metafile (EMF) format. /// </summary> private static readonly Guid ImageFormatEMF = new Guid("B96B3CAC-0728-11D3-9D7B-0000F81EF32E"); /// <summary> /// Indicates the Exif (Exchangeable Image File) format. /// </summary> private static readonly Guid ImageFormatEXIF = new Guid("B96B3CB2-0728-11D3-9D7B-0000F81EF32E"); /// <summary> /// Indicates the Graphics Interchange Format (GIF) format. /// </summary> private static readonly Guid ImageFormatGIF = new Guid("B96B3CB0-0728-11D3-9D7B-0000F81EF32E"); /// <summary> /// Indicates the Icon format. /// </summary> private static readonly Guid ImageFormatIcon = new Guid("B96B3CB5-0728-11D3-9D7B-0000F81EF32E"); /// <summary> /// Indicates the JPEG format. /// </summary> private static readonly Guid ImageFormatJPEG = new Guid("B96B3CAE-0728-11D3-9D7B-0000F81EF32E"); /// <summary> /// Indicates that the image was constructed from a memory bitmap. /// </summary> private static readonly Guid ImageFormatMemoryBMP = new Guid("B96B3CAB-0728-11D3-9D7B-0000F81EF32E"); /// <summary> /// Indicates the Portable Network Graphics (PNG) format. /// </summary> private static readonly Guid ImageFormatPNG = new Guid("B96B3CAF-0728-11D3-9D7B-0000F81EF32E"); /// <summary> /// Indicates the Tagged Image File Format (TIFF) format. /// </summary> private static readonly Guid ImageFormatTIFF = new Guid("B96B3CB1-0728-11D3-9D7B-0000F81EF32E"); /// <summary> /// Indicates that Windows GDI+ is unable to determine the format. /// </summary> private static readonly Guid ImageFormatUndefined = new Guid("B96B3CA9-0728-11D3-9D7B-0000F81EF32E"); /// <summary> /// Indicates the Windows Metafile Format (WMF) format. /// </summary> private static readonly Guid ImageFormatWMF = new Guid("B96B3CAD-0728-11D3-9D7B-0000F81EF32E"); internal const int S_OK = 0; /// <summary> /// Gets the ImageType of the given file /// </summary> /// <param name="fileName">Path of the file to get the info of</param> /// <returns>ImageType of the given file</returns> public static ImageType GetImageType(string fileName) { IImage imagingImage = null; try { if (File.Exists(fileName)) { using (StreamOnFile fileStream = new StreamOnFile(fileName)) { imagingImage = BitmapProperties.GetImage(fileStream); if (imagingImage != null) { ImageInfo info = new ImageInfo(); uint ret = imagingImage.GetImageInfo(ref info); if (ret == BitmapProperties.S_OK) { if (info.RawDataFormat == BitmapProperties.ImageFormatBMP) { return ImageType.BMP; } else if (info.RawDataFormat == BitmapProperties.ImageFormatEMF) { return ImageType.EMF; } else if (info.RawDataFormat == BitmapProperties.ImageFormatEXIF) { return ImageType.EXIF; } else if (info.RawDataFormat == BitmapProperties.ImageFormatGIF) { return ImageType.GIF; } else if (info.RawDataFormat == BitmapProperties.ImageFormatIcon) { return ImageType.Icon; } else if (info.RawDataFormat == BitmapProperties.ImageFormatJPEG) { return ImageType.JPEG; } else if (info.RawDataFormat == BitmapProperties.ImageFormatMemoryBMP) { return ImageType.MemoryBMP; } else if (info.RawDataFormat == BitmapProperties.ImageFormatPNG) { return ImageType.PNG; } else if (info.RawDataFormat == BitmapProperties.ImageFormatTIFF) { return ImageType.TIFF; } else if (info.RawDataFormat == BitmapProperties.ImageFormatWMF) { return ImageType.WMF; } } } } } return ImageType.Undefined; } finally { if (imagingImage != null) { Marshal.ReleaseComObject(imagingImage); } } } private static IImage GetImage(StreamOnFile stream) { IImagingFactory factory = null; try { factory = (IImagingFactory)Activator.CreateInstance(Type.GetTypeFromCLSID(new Guid("327ABDA8-072B-11D3-9D7B-0000F81EF32E"))); if (factory != null) { IImage imagingImage; uint result = factory.CreateImageFromStream(stream, out imagingImage); if (result == BitmapProperties.S_OK) { return imagingImage; } } } catch (COMException) { } catch (IOException) { } finally { if (factory != null) { Marshal.ReleaseComObject(factory); } } return null; } }
您可以从以下代码中获取图像types：
//get your image from bytaArrayToImage Image img = byteArrayToImage(new byte[] { }); //get the format/file type string ext = new ImageFormatConverter().ConvertToString(img.RawFormat);
