/// <summary>
/// Retrieves the metadata block or item identified by a metadata query expression.
/// </summary>
/// <param name="name">The query expression to the requested metadata block or item.</param>
/// <param name="value">The metadata block or item requested or null if not found.</param>
/// <returns>True when the metadata block or item was found, otherwise false.</returns>
/// <remarks>
/// GetMetadataByName uses metadata query expressions to access embedded metadata. For more information on the metadata query language, see the Metadata Query Language Overview.
/// <br/>
/// If multiple blocks or items exist that are expressed by the same query expression, the first metadata block or item found will be returned.
/// </remarks>
public static bool TryGetMetadataByName(this IWICMetadataQueryReader metadataQueryReader, string name, out object?value)
{
if (metadataQueryReader is null)
{
throw new NullReferenceException();
}
if (name is null)
{
throw new ArgumentNullException(nameof(name));
}
var variant = new PROPVARIANT();
try
{
metadataQueryReader.GetMetadataByName(name, ref variant);
value = PropVariantHelper.Decode(variant);
return(true);
}
catch (COMException ex) when(ex.ErrorCode == WinCodecError.PROPERTY_NOT_FOUND)
{
value = null;
return(false);
}
finally
{
PropVariantHelper.Free(variant);
}
}
private void GetBackgroundColor(IWICMetadataQueryReader wicMetadataQueryReader)
{
// 如果图片里面包含了 global palette 就需要获取 palette 和背景色
var propertyVariant = new PROPVARIANT();
wicMetadataQueryReader.GetMetadataByName("/logscrdesc/GlobalColorTableFlag", ref propertyVariant);
byte backgroundIndex = 0;
var globalPalette = (propertyVariant.Type & VARTYPE.VT_BOOL) == VARTYPE.VT_BOOL &&
propertyVariant.Value.UI1 > 0;
if (globalPalette)
{
propertyVariant = new PROPVARIANT();
wicMetadataQueryReader.GetMetadataByName("/logscrdesc/BackgroundColorIndex", ref propertyVariant);
if ((propertyVariant.Type & VARTYPE.VT_UI1) == VARTYPE.VT_UI1)
{
backgroundIndex = propertyVariant.Value.UI1;
}
var wicPalette = WicImagingFactory.CreatePalette();
WicBitmapDecoder.CopyPalette(wicPalette);
}
}
public static bool TryGetMetadataByName(this IWICMetadataQueryReader meta, string name, out PropVariant val)
{
val = null;
int hr = ProxyFunctions.GetMetadataByName(meta, name, IntPtr.Zero);
if (hr >= 0)
{
val = new PropVariant();
meta.GetMetadataByName(name, val);
}
return(hr >= 0);
}
public ImageSource(byte[] buffer)
{
if (buffer == null || buffer.Length == 0)
{
throw new ArgumentException("Image buffer does not contain a valid image to load.", "buffer");
}
this.buffer = buffer;
IWICImagingFactory iwicimagingFactory = WicUtility.CreateFactory();
IWICBitmapFrameDecode iwicbitmapFrameDecode = iwicimagingFactory.Load(this.ImageStream);
int num;
int num2;
iwicbitmapFrameDecode.GetSize(out num, out num2);
this.Width = (float)num;
this.Height = (float)num2;
IWICMetadataQueryReader iwicmetadataQueryReader = null;
try
{
iwicbitmapFrameDecode.GetMetadataQueryReader(out iwicmetadataQueryReader);
string s;
DateTime value;
if (iwicmetadataQueryReader.TryGetMetadataProperty("/app1/ifd/exif/subifd:{uint=36867}", out s) && DateTime.TryParseExact(s, "yyyy:MM:dd HH:mm:ss", null, DateTimeStyles.None, out value))
{
this.DateTaken = new DateTime?(value);
}
}
catch (Exception)
{
}
try
{
ushort value2;
if (iwicmetadataQueryReader.TryGetMetadataProperty("/app1/ifd/{ushort=274}", out value2))
{
this.Orientation = ImageSource.TransformOptionsFromUshort(value2);
}
else
{
this.Orientation = WICBitmapTransformOptions.WICBitmapTransformRotate0;
}
}
catch (Exception)
{
}
GraphicsInteropNativeMethods.SafeReleaseComObject(iwicmetadataQueryReader);
GraphicsInteropNativeMethods.SafeReleaseComObject(iwicbitmapFrameDecode);
GraphicsInteropNativeMethods.SafeReleaseComObject(iwicimagingFactory);
}
public static IEnumerable <string> GetNamesRecursive(this IWICMetadataQueryReader reader)
{
foreach (var name in reader.GetNames())
{
var val = reader.GetMetadataByName(name);
if (val is IWICMetadataQueryReader)
{
foreach (var childName in GetNamesRecursive((IWICMetadataQueryReader)val))
{
yield return(name + childName);
}
}
else
{
yield return(name);
}
}
}
public static bool TryGetMetadataByName(this IWICMetadataQueryReader meta, string name, [NotNullWhen(true)] out PropVariant?value)
{
value = null;
int hr = ProxyFunctions.GetMetadataByName(meta, name, IntPtr.Zero);
if (hr >= 0)
{
value = new PropVariant();
var pvMarshal = PropVariant.Marshaler.GetInstance(null);
var pvNative = pvMarshal.MarshalManagedToNative(value);
hr = ProxyFunctions.GetMetadataByName(meta, name, pvNative);
pvMarshal.MarshalNativeToManaged(pvNative);
pvMarshal.CleanUpNativeData(pvNative);
}
return(hr >= 0);
}
public static bool TryGetMetadataByName <T>(this IWICMetadataQueryReader metadataQueryReader, string name, out T value)
{
var variant = new PROPVARIANT();
try
{
metadataQueryReader.GetMetadataByName(name, ref variant);
return(TryDecode(ref variant, out value));
}
catch (COMException ex) when(ex.ErrorCode == HResult.WINCODEC_ERR_PROPERTYNOTFOUND)
{
value = default(T);
return(false);
}
finally
{
Dispose(ref variant);
}
}
public static bool TryGetMetadataProperty <T>(this IWICMetadataQueryReader queryReader, string propertyPath, out T value)
{
if (queryReader == null)
{
throw new ArgumentNullException("queryReader");
}
value = default(T);
PROPVARIANT propvariant = default(PROPVARIANT);
int metadataByName = queryReader.GetMetadataByName(propertyPath, out propvariant);
if (-2003292352 != metadataByName)
{
GraphicsInteropNativeMethods.CheckNativeResult(metadataByName);
value = (T)((object)propvariant.Value);
propvariant.Dispose();
return(true);
}
propvariant.Dispose();
return(false);
}
/// <summary>
/// Retrieves the metadata block or item identified by a metadata query expression.
/// </summary>
/// <param name="name">The query expression to the requested metadata block or item.</param>
/// <returns>The metadata block or item requested.</returns>
/// <exception cref="COMException">Thrown when the metadata block or item was not found (HRESULT 0x88982F40).</exception>
/// <remarks>
/// GetMetadataByName uses metadata query expressions to access embedded metadata. For more information on the metadata query language, see the Metadata Query Language Overview.
/// <br/>
/// If multiple blocks or items exist that are expressed by the same query expression, the first metadata block or item found will be returned.
/// </remarks>
public static object GetMetadataByName(this IWICMetadataQueryReader metadataQueryReader, string name)
{
if (metadataQueryReader is null)
{
throw new NullReferenceException();
}
if (name is null)
{
throw new ArgumentNullException(nameof(name));
}
var variant = new PROPVARIANT();
try
{
metadataQueryReader.GetMetadataByName(name, ref variant);
return(PropVariantHelper.Decode(variant));
}
finally
{
PropVariantHelper.Free(variant);
}
}
public void GetMetadataQueryReader(out IWICMetadataQueryReader ppIMetadataQueryReader)
{
Log.Trace("GetMetadataQueryReader called");
ppIMetadataQueryReader = new MetadataEnumerator(exif);
Log.Trace("GetMetadataQueryReader finished");
}
public extern IWICMetadataQueryWriter CreateQueryWriterFromReader([In, MarshalAs(UnmanagedType.Interface)] IWICMetadataQueryReader pIQueryReader, [In] ref Guid pguidVendor);
public static string GetLocation(this IWICMetadataQueryReader metadataQueryReader)
{
FetchIntoBuffer <char> fetcher = metadataQueryReader.GetLocation;
return(fetcher.FetchString());
}
public static bool TryGetMetadataQueryReader(this IWICBitmapFrameDecode frame, out IWICMetadataQueryReader rdr)
{
int hr = ProxyFunctions.GetMetadataQueryReader(frame, out rdr);
return(hr >= 0);
}
public static bool HasMetadataName(this IWICMetadataQueryReader meta, string name)
{
int hr = GetMetadataByName(meta, name, IntPtr.Zero);
return(hr >= 0);
}
private extern static int GetMetadataByName(IWICMetadataQueryReader THIS_PTR, [MarshalAs(UnmanagedType.LPWStr)] string wzName, IntPtr pvarValue);
public static IWICMetadataQueryWriter CreateQueryWriterFromReader(this IWICImagingFactory imagingFactory, IWICMetadataQueryReader pIQueryReader, Guid?pguidVendor = null)
{
using (var pguidVendorPtr = CoTaskMemPtr.From(pguidVendor))
{
return(imagingFactory.CreateQueryWriterFromReader(pIQueryReader, pguidVendorPtr));
}
}
unsafe public static void UpdateGifAnimationContext(WicGifContainer cont, IWICBitmapSource src, IWICMetadataQueryReader meta)
{
Debug.Assert(cont.AnimationContext != null);
var anictx = cont.AnimationContext;
const int bytesPerPixel = 4;
var finfo = GetGifFrameInfo(cont, src, meta);
var fbuff = anictx.FrameBufferSource ??= new FrameBufferSource(cont.ScreenWidth, cont.ScreenHeight, PixelFormat.Bgra32Bpp);
var bspan = fbuff.Span;
fbuff.ResumeTiming();
// Most GIF viewers clear the background to transparent instead of the background color when the next frame has transparency
bool ftrans = meta.GetValueOrDefault <bool>(Wic.Metadata.Gif.TransparencyFlag);
if (!finfo.FullScreen && anictx.LastDisposal == GifDisposalMethod.RestoreBackground)
{
MemoryMarshal.Cast <byte, uint>(bspan).Fill(ftrans ? 0 : cont.BackgroundColor);
}
// Similarly, they overwrite a background color with transparent pixels but overlay instead when the previous frame is preserved
var fspan = bspan.Slice(finfo.Top * fbuff.Stride + finfo.Left * bytesPerPixel);
fixed(byte *buff = fspan)
{
if (!ftrans || anictx.LastDisposal == GifDisposalMethod.RestoreBackground)
{
src.CopyPixels(WICRect.Null, (uint)fbuff.Stride, (uint)fspan.Length, (IntPtr)buff);
}
else
{
using var overlay = new OverlayTransform(fbuff, src.AsPixelSource(nameof(IWICBitmapFrameDecode)), finfo.Left, finfo.Top, true, true);
overlay.CopyPixels(new PixelArea(finfo.Left, finfo.Top, finfo.Width, finfo.Height), fbuff.Stride, fspan.Length, (IntPtr)buff);
}
}
fbuff.PauseTiming();
}
/// <summary>
/// Retrieves the current path relative to the root metadata block.
/// </summary>
/// <returns>The current namespace location.</returns>
/// <remarks>
/// If the query reader is relative to the top of the metadata hierarchy, it will return a single-char string.
/// <br/>
/// If the query reader is relative to a nested metadata block, this method will return the path to the current query reader.
/// </remarks>
public static string GetLocation(this IWICMetadataQueryReader metadataQueryReader)
{
return(FetchIntoBufferHelper.FetchString(metadataQueryReader.GetLocation));
}
/// <summary>
/// Gets the names of all metadata items at the current relative location within the metadata hierarchy.
/// </summary>
/// <returns>An enumerable that contains query strings that can be used in the current <see cref="IWICMetadataQueryReader"/>.</returns>
/// <remarks>
/// The retrieved enumerable only contains query strings for the metadata blocks and items in the current level of the hierarchy.
/// </remarks>
public static IEnumerable <string> GetNames(this IWICMetadataQueryReader metadataQueryReader)
{
return(metadataQueryReader.GetEnumerator().AsEnumerable());
}
private extern static int GetMetadataQueryReader(IWICBitmapFrameDecode THIS_PTR, out IWICMetadataQueryReader ppIMetadataQueryReader);
public void GetMetadataQueryReader(out IWICMetadataQueryReader ppIMetadataQueryReader)
{
Log.Trace("GetMetadataQueryReader called");
ppIMetadataQueryReader = new MetadataEnumerator(exif);
Log.Trace("GetMetadataQueryReader finished");
}
public static (int Left, int Top, int Width, int Height, bool Alpha, bool FullScreen, GifDisposalMethod Disposal) GetGifFrameInfo(WicGifContainer cont, IWICBitmapSource frame, IWICMetadataQueryReader meta)
{
frame.GetSize(out uint width, out uint height);
int left = 0, top = 0;
var disp = ((GifDisposalMethod)meta.GetValueOrDefault <byte>(Wic.Metadata.Gif.FrameDisposal)).Clamp();
bool trans = meta.GetValueOrDefault <bool>(Wic.Metadata.Gif.TransparencyFlag);
bool full = width == cont.ScreenWidth && height == cont.ScreenHeight;
if (!full)
{
left = meta.GetValueOrDefault <ushort>(Wic.Metadata.Gif.FrameLeft);
top = meta.GetValueOrDefault <ushort>(Wic.Metadata.Gif.FrameTop);
}
return(left, top, (int)width, (int)height, trans, full, disp);
}
