WPF 显示GIF动画

来源:转载


简单的通过GifBitmapDecoder解析GIF图片,获取gif帧数和每一帧数据,然后通过时间切换显示,效果如下:

代码如下:

namespace GIfImageApplication{ public class GifImageExceptionRoutedEventArgs : RoutedEventArgs { public Exception ErrorException; public GifImageExceptionRoutedEventArgs(RoutedEvent routedEvent, object obj) : base(routedEvent, obj) { } } public class WebReadState { public WebRequest webRequest; public MemoryStream memoryStream; public Stream readStream; public byte[] buffer; } public class GifImage : System.Windows.Controls.UserControl { private GifAnimation gifAnimation = null; private Image image = null; public static readonly DependencyProperty ForceGifAnimProperty = DependencyProperty.Register("ForceGifAnim", typeof(bool), typeof(GifImage), new FrameworkPropertyMetadata(false)); public bool ForceGifAnim { get { return (bool)this.GetValue(ForceGifAnimProperty); } set { this.SetValue(ForceGifAnimProperty, value); } } public static readonly DependencyProperty SourceProperty = DependencyProperty.Register("Source", typeof(string), typeof(GifImage), new FrameworkPropertyMetadata("", FrameworkPropertyMetadataOptions.AffectsMeasure | FrameworkPropertyMetadataOptions.AffectsRender, new PropertyChangedCallback(OnSourceChanged))); private static void OnSourceChanged(DependencyObject d, DependencyPropertyChangedEventArgs e) { GifImage obj = (GifImage)d; string s = (string)e.NewValue; obj.CreateFromSourceString(s); } public string Source { get { return (string)this.GetValue(SourceProperty); } set { this.SetValue(SourceProperty, value); } } public static readonly DependencyProperty StretchProperty = DependencyProperty.Register("Stretch", typeof(Stretch), typeof(GifImage), new FrameworkPropertyMetadata(Stretch.Fill, FrameworkPropertyMetadataOptions.AffectsMeasure, new PropertyChangedCallback(OnStretchChanged))); private static void OnStretchChanged(DependencyObject d, DependencyPropertyChangedEventArgs e) { GifImage obj = (GifImage)d; Stretch s = (Stretch)e.NewValue; if (obj.gifAnimation != null) { obj.gifAnimation.Stretch = s; } else if (obj.image != null) { obj.image.Stretch = s; } } public Stretch Stretch { get { return (Stretch)this.GetValue(StretchProperty); } set { this.SetValue(StretchProperty, value); } } public static readonly DependencyProperty StretchDirectionProperty = DependencyProperty.Register("StretchDirection", typeof(StretchDirection), typeof(GifImage), new FrameworkPropertyMetadata(StretchDirection.Both, FrameworkPropertyMetadataOptions.AffectsMeasure, new PropertyChangedCallback(OnStretchDirectionChanged))); private static void OnStretchDirectionChanged(DependencyObject d, DependencyPropertyChangedEventArgs e) { GifImage obj = (GifImage)d; StretchDirection s = (StretchDirection)e.NewValue; if (obj.gifAnimation != null) { obj.gifAnimation.StretchDirection = s; } else if (obj.image != null) { obj.image.StretchDirection = s; } } public StretchDirection StretchDirection { get { return (StretchDirection)this.GetValue(StretchDirectionProperty); } set { this.SetValue(StretchDirectionProperty, value); } } public delegate void ExceptionRoutedEventHandler(object sender, GifImageExceptionRoutedEventArgs args); public static readonly RoutedEvent ImageFailedEvent = EventManager.RegisterRoutedEvent("ImageFailed", RoutingStrategy.Bubble, typeof(ExceptionRoutedEventHandler), typeof(GifImage)); public event ExceptionRoutedEventHandler ImageFailed { add { AddHandler(ImageFailedEvent, value); } remove { RemoveHandler(ImageFailedEvent, value); } } void image_ImageFailed(object sender, ExceptionRoutedEventArgs e) { RaiseImageFailedEvent(e.ErrorException); } void RaiseImageFailedEvent(Exception exp) { GifImageExceptionRoutedEventArgs newArgs = new GifImageExceptionRoutedEventArgs(ImageFailedEvent, this); newArgs.ErrorException = exp; RaiseEvent(newArgs); } private void DeletePreviousImage() { if (image != null) { this.RemoveLogicalChild(image); image = null; } if (gifAnimation != null) { this.RemoveLogicalChild(gifAnimation); gifAnimation = null; } } private void CreateNonGifAnimationImage() { image = new Image(); image.ImageFailed += new EventHandler<ExceptionRoutedEventArgs>(image_ImageFailed); ImageSource src = (ImageSource)(new ImageSourceConverter().ConvertFromString(Source)); image.Source = src; image.Stretch = Stretch; image.StretchDirection = StretchDirection; this.AddChild(image); } private void CreateGifAnimation(MemoryStream memoryStream) { gifAnimation = new GifAnimation(); gifAnimation.CreateGifAnimation(memoryStream); gifAnimation.Stretch = Stretch; gifAnimation.StretchDirection = StretchDirection; this.AddChild(gifAnimation); } private void CreateFromSourceString(string source) { DeletePreviousImage(); Uri uri; try { uri = new Uri(source, UriKind.RelativeOrAbsolute); } catch (Exception exp) { RaiseImageFailedEvent(exp); return; } if (source.Trim().ToUpper().EndsWith(".GIF") || ForceGifAnim) { if (!uri.IsAbsoluteUri) { GetGifStreamFromPack(uri); } else { string leftPart = uri.GetLeftPart(UriPartial.Scheme); if (leftPart == "http://" || leftPart == "ftp://" || leftPart == "file://") { GetGifStreamFromHttp(uri); } else if (leftPart == "pack://") { GetGifStreamFromPack(uri); } else { CreateNonGifAnimationImage(); } } } else { CreateNonGifAnimationImage(); } } private delegate void WebRequestFinishedDelegate(MemoryStream memoryStream); private void WebRequestFinished(MemoryStream memoryStream) { CreateGifAnimation(memoryStream); } private delegate void WebRequestErrorDelegate(Exception exp); private void WebRequestError(Exception exp) { RaiseImageFailedEvent(exp); } private void WebResponseCallback(IAsyncResult asyncResult) { WebReadState webReadState = (WebReadState)asyncResult.AsyncState; WebResponse webResponse; try { webResponse = webReadState.webRequest.EndGetResponse(asyncResult); webReadState.readStream = webResponse.GetResponseStream(); webReadState.buffer = new byte[100000]; webReadState.readStream.BeginRead(webReadState.buffer, 0, webReadState.buffer.Length, new AsyncCallback(WebReadCallback), webReadState); } catch (WebException exp) { this.Dispatcher.Invoke(DispatcherPriority.Render, new WebRequestErrorDelegate(WebRequestError), exp); } } private void WebReadCallback(IAsyncResult asyncResult) { WebReadState webReadState = (WebReadState)asyncResult.AsyncState; int count = webReadState.readStream.EndRead(asyncResult); if (count > 0) { webReadState.memoryStream.Write(webReadState.buffer, 0, count); try { webReadState.readStream.BeginRead(webReadState.buffer, 0, webReadState.buffer.Length, new AsyncCallback(WebReadCallback), webReadState); } catch (WebException exp) { this.Dispatcher.Invoke(DispatcherPriority.Render, new WebRequestErrorDelegate(WebRequestError), exp); } } else { this.Dispatcher.Invoke(DispatcherPriority.Render, new WebRequestFinishedDelegate(WebRequestFinished), webReadState.memoryStream); } } private void GetGifStreamFromHttp(Uri uri) { try { WebReadState webReadState = new WebReadState(); webReadState.memoryStream = new MemoryStream(); webReadState.webRequest = WebRequest.Create(uri); webReadState.webRequest.Timeout = 10000; webReadState.webRequest.BeginGetResponse(new AsyncCallback(WebResponseCallback), webReadState); } catch (SecurityException) { CreateNonGifAnimationImage(); } } private void ReadGifStreamSynch(Stream s) { byte[] gifData; MemoryStream memoryStream; using (s) { memoryStream = new MemoryStream((int)s.Length); BinaryReader br = new BinaryReader(s); gifData = br.ReadBytes((int)s.Length); memoryStream.Write(gifData, 0, (int)s.Length); memoryStream.Flush(); } CreateGifAnimation(memoryStream); } private void GetGifStreamFromPack(Uri uri) { try { StreamResourceInfo streamInfo; if (!uri.IsAbsoluteUri) { streamInfo = Application.GetContentStream(uri); if (streamInfo == null) { streamInfo = Application.GetResourceStream(uri); } } else { if (uri.GetLeftPart(UriPartial.Authority).Contains("siteoforigin")) { streamInfo = Application.GetRemoteStream(uri); } else { streamInfo = Application.GetContentStream(uri); if (streamInfo == null) { streamInfo = Application.GetResourceStream(uri); } } } if (streamInfo == null) { throw new FileNotFoundException("Resource not found.", uri.ToString()); } ReadGifStreamSynch(streamInfo.Stream); } catch (Exception exp) { RaiseImageFailedEvent(exp); } } } class GifAnimation : Viewbox { private class HedmGifFrame : Image { public int delayTime; public int disposalMethod; public int left; public int top; public int width; public int height; } private Canvas canvas = null; private List<HedmGifFrame> frameList = null; private int frameCounter = 0; private int numberOfFrames = 0; private int numberOfLoops = -1; private int currentLoop = 0; private int logicalWidth = 0; private int logicalHeight = 0; private DispatcherTimer frameTimer = null; private HedmGifFrame currentParseGifFrame; public GifAnimation() { canvas = new Canvas(); this.Child = canvas; } private void Reset() { if (frameList != null) { frameList.Clear(); } frameList = null; frameCounter = 0; numberOfFrames = 0; numberOfLoops = -1; currentLoop = 0; logicalWidth = 0; logicalHeight = 0; if (frameTimer != null) { frameTimer.Stop(); frameTimer = null; } } #region PARSE private void ParseGif(byte[] gifData) { frameList = new List<HedmGifFrame>(); currentParseGifFrame = new HedmGifFrame(); ParseGifDataStream(gifData, 0); } private int ParseBlock(byte[] gifData, int offset) { switch (gifData[offset]) { case 0x21: if (gifData[offset + 1] == 0xF9) { return ParseGraphicControlExtension(gifData, offset); } else { return ParseExtensionBlock(gifData, offset); } case 0x2C: offset = ParseGraphicBlock(gifData, offset); frameList.Add(currentParseGifFrame); currentParseGifFrame = new HedmGifFrame(); return offset; case 0x3B: return -1; default: throw new Exception("GIF format incorrect: missing graphic block or special-purpose block. "); } } private int ParseGraphicControlExtension(byte[] gifData, int offset) { int returnOffset = offset; int length = gifData[offset + 2]; returnOffset = offset + length + 2 + 1; byte packedField = gifData[offset + 3]; currentParseGifFrame.disposalMethod = (packedField & 0x1C) >> 2; int delay = BitConverter.ToUInt16(gifData, offset + 4); currentParseGifFrame.delayTime = delay; while (gifData[returnOffset] != 0x00) { returnOffset = returnOffset + gifData[returnOffset] + 1; } returnOffset++; return returnOffset; } private int ParseLogicalScreen(byte[] gifData, int offset) { logicalWidth = BitConverter.ToUInt16(gifData, offset); logicalHeight = BitConverter.ToUInt16(gifData, offset + 2); byte packedField = gifData[offset + 4]; bool hasGlobalColorTable = (int)(packedField & 0x80) > 0 ? true : false; int currentIndex = offset + 7; if (hasGlobalColorTable) { int colorTableLength = packedField & 0x07; colorTableLength = (int)Math.Pow(2, colorTableLength + 1) * 3; currentIndex = currentIndex + colorTableLength; } return currentIndex; } private int ParseGraphicBlock(byte[] gifData, int offset) { currentParseGifFrame.left = BitConverter.ToUInt16(gifData, offset + 1); currentParseGifFrame.top = BitConverter.ToUInt16(gifData, offset + 3); currentParseGifFrame.width = BitConverter.ToUInt16(gifData, offset + 5); currentParseGifFrame.height = BitConverter.ToUInt16(gifData, offset + 7); if (currentParseGifFrame.width > logicalWidth) { logicalWidth = currentParseGifFrame.width; } if (currentParseGifFrame.height > logicalHeight) { logicalHeight = currentParseGifFrame.height; } byte packedField = gifData[offset + 9]; bool hasLocalColorTable = (int)(packedField & 0x80) > 0 ? true : false; int currentIndex = offset + 9; if (hasLocalColorTable) { int colorTableLength = packedField & 0x07; colorTableLength = (int)Math.Pow(2, colorTableLength + 1) * 3; currentIndex = currentIndex + colorTableLength; } currentIndex++; currentIndex++; while (gifData[currentIndex] != 0x00) { int length = gifData[currentIndex]; currentIndex = currentIndex + gifData[currentIndex]; currentIndex++; } currentIndex = currentIndex + 1; return currentIndex; } private int ParseExtensionBlock(byte[] gifData, int offset) { int returnOffset = offset; int length = gifData[offset + 2]; returnOffset = offset + length + 2 + 1; if (gifData[offset + 1] == 0xFF && length > 10) { string netscape = System.Text.ASCIIEncoding.ASCII.GetString(gifData, offset + 3, 8); if (netscape == "NETSCAPE") { numberOfLoops = BitConverter.ToUInt16(gifData, offset + 16); if (numberOfLoops > 0) { numberOfLoops++; } } } while (gifData[returnOffset] != 0x00) { returnOffset = returnOffset + gifData[returnOffset] + 1; } returnOffset++; return returnOffset; } private int ParseHeader(byte[] gifData, int offset) { string str = System.Text.ASCIIEncoding.ASCII.GetString(gifData, offset, 3); if (str != "GIF") { throw new Exception("Not a proper GIF file: missing GIF header"); } return 6; } private void ParseGifDataStream(byte[] gifData, int offset) { offset = ParseHeader(gifData, offset); offset = ParseLogicalScreen(gifData, offset); while (offset != -1) { offset = ParseBlock(gifData, offset); } } #endregion public void CreateGifAnimation(MemoryStream memoryStream) { try { Reset(); byte[] gifData = memoryStream.GetBuffer(); // Use GetBuffer so that there is no memory copy GifBitmapDecoder decoder = new GifBitmapDecoder(memoryStream, BitmapCreateOptions.PreservePixelFormat, BitmapCacheOption.Default); numberOfFrames = decoder.Frames.Count; try { ParseGif(gifData); } catch { throw new FileFormatException("Unable to parse Gif file format."); } for (int i = 0; i < decoder.Frames.Count; i++) { frameList[i].Source = decoder.Frames[i]; frameList[i].Visibility = Visibility.Hidden; canvas.Children.Add(frameList[i]); Canvas.SetLeft(frameList[i], frameList[i].left); Canvas.SetTop(frameList[i], frameList[i].top); Canvas.SetZIndex(frameList[i], i); } canvas.Height = logicalHeight; canvas.Width = logicalWidth; frameList[0].Visibility = Visibility.Visible; for (int i = 0; i < frameList.Count; i++) { Console.WriteLine(frameList[i].disposalMethod.ToString() + " " + frameList[i].width.ToString() + " " + frameList[i].delayTime.ToString()); } if (frameList.Count > 1) { if (numberOfLoops == -1) { numberOfLoops = 1; } frameTimer = new System.Windows.Threading.DispatcherTimer(); frameTimer.Tick += NextFrame; frameTimer.Interval = new TimeSpan(0, 0, 0, 0, frameList[0].delayTime * 10); frameTimer.Start(); } } finally { } } public void NextFrame() { NextFrame(null, null); } public void NextFrame(object sender, EventArgs e) { frameTimer.Stop(); if (numberOfFrames == 0) return; if (frameList[frameCounter].disposalMethod == 2) { frameList[frameCounter].Visibility = Visibility.Hidden; } if (frameList[frameCounter].disposalMethod >= 3) { frameList[frameCounter].Visibility = Visibility.Hidden; } frameCounter++; if (frameCounter < numberOfFrames) { frameList[frameCounter].Visibility = Visibility.Visible; frameTimer.Interval = new TimeSpan(0, 0, 0, 0, frameList[frameCounter].delayTime * 10); frameTimer.Start(); } else { if (numberOfLoops != 0) { currentLoop++; } if (currentLoop < numberOfLoops || numberOfLoops == 0) { for (int f = 0; f < frameList.Count; f++) { frameList[f].Visibility = Visibility.Hidden; } frameCounter = 0; frameList[frameCounter].Visibility = Visibility.Visible; frameTimer.Interval = new TimeSpan(0, 0, 0, 0, frameList[frameCounter].delayTime * 10); frameTimer.Start(); } } } }}

使用:

 <Gif:GifImage Source="loading.gif" ></Gif:GifImage>

 



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