How do I get an animated gif to work in WPF?

Question

What control type should I use - Image, MediaElement, etc.?

Answer 1

Here is my version of animated image control. You can use standard property Source for specifying image source. I further improved it. I am a russian, project is russian so comments are also in Russian. But anyway you should be able understand everything without comments. :)

/// 

/// Control the "Images", which supports animated GIF.
/// 
public class AnimatedImage : Image
{
    #region Public properties

    /// 

    /// Gets / sets the number of the current frame.
    /// 
    public int FrameIndex
    {
        get { return (int) GetValue(FrameIndexProperty); }
        set { SetValue(FrameIndexProperty, value); }
    }

    /// 

    /// Gets / sets the image that will be drawn.
    /// 
    public new ImageSource Source
    {
        get { return (ImageSource) GetValue(SourceProperty); }
        set { SetValue(SourceProperty, value); }
    }

    #endregion

    #region Protected interface

    /// 

    /// Provides derived classes an opportunity to handle changes to the Source property.
    /// 
    protected virtual void OnSourceChanged(DependencyPropertyChangedEventArgs aEventArgs)
    {
        ClearAnimation();

        BitmapImage lBitmapImage = aEventArgs.NewValue as BitmapImage;

        if (lBitmapImage == null)
        {
            ImageSource lImageSource = aEventArgs.NewValue as ImageSource;
            base.Source = lImageSource;
            return;
        }

        if (!IsAnimatedGifImage(lBitmapImage))
        {
            base.Source = lBitmapImage;
            return;
        }

        PrepareAnimation(lBitmapImage);
    }

    #endregion

    #region Private properties

    private Int32Animation Animation { get; set; }
    private GifBitmapDecoder Decoder { get; set; }
    private bool IsAnimationWorking { get; set; }

    #endregion

    #region Private methods

    private void ClearAnimation()
    {
        if (Animation != null)
        {
            BeginAnimation(FrameIndexProperty, null);
        }

        IsAnimationWorking = false;
        Animation = null;
        Decoder = null;
    }

    private void PrepareAnimation(BitmapImage aBitmapImage)
    {
        Debug.Assert(aBitmapImage != null);

        if (aBitmapImage.UriSource != null)
        {
            Decoder = new GifBitmapDecoder(
                aBitmapImage.UriSource,
                BitmapCreateOptions.PreservePixelFormat,
                BitmapCacheOption.Default);
        }
        else
        {
            aBitmapImage.StreamSource.Position = 0;
            Decoder = new GifBitmapDecoder(
                aBitmapImage.StreamSource,
                BitmapCreateOptions.PreservePixelFormat,
                BitmapCacheOption.Default);
        }

        Animation =
            new Int32Animation(
                0,
                Decoder.Frames.Count - 1,
                new Duration(
                    new TimeSpan(
                        0,
                        0,
                        0,
                        Decoder.Frames.Count / 10,
                        (int) ((Decoder.Frames.Count / 10.0 - Decoder.Frames.Count / 10) * 1000))))
                {
                    RepeatBehavior = RepeatBehavior.Forever
                };

        base.Source = Decoder.Frames[0];
        BeginAnimation(FrameIndexProperty, Animation);
        IsAnimationWorking = true;
    }

    private bool IsAnimatedGifImage(BitmapImage aBitmapImage)
    {
        Debug.Assert(aBitmapImage != null);

        bool lResult = false;
        if (aBitmapImage.UriSource != null)
        {
            BitmapDecoder lBitmapDecoder = BitmapDecoder.Create(
                aBitmapImage.UriSource,
                BitmapCreateOptions.PreservePixelFormat,
                BitmapCacheOption.Default);
            lResult = lBitmapDecoder is GifBitmapDecoder;
        }
        else if (aBitmapImage.StreamSource != null)
        {
            try
            {
                long lStreamPosition = aBitmapImage.StreamSource.Position;
                aBitmapImage.StreamSource.Position = 0;
                GifBitmapDecoder lBitmapDecoder =
                    new GifBitmapDecoder(
                        aBitmapImage.StreamSource,
                        BitmapCreateOptions.PreservePixelFormat,
                        BitmapCacheOption.Default);
                lResult = lBitmapDecoder.Frames.Count > 1;

                aBitmapImage.StreamSource.Position = lStreamPosition;
            }
            catch
            {
                lResult = false;
            }
        }

        return lResult;
    }

    private static void ChangingFrameIndex
        (DependencyObject aObject, DependencyPropertyChangedEventArgs aEventArgs)
    {
        AnimatedImage lAnimatedImage = aObject as AnimatedImage;

        if (lAnimatedImage == null || !lAnimatedImage.IsAnimationWorking)
        {
            return;
        }

        int lFrameIndex = (int) aEventArgs.NewValue;
        ((Image) lAnimatedImage).Source = lAnimatedImage.Decoder.Frames[lFrameIndex];
        lAnimatedImage.InvalidateVisual();
    }

    /// 

    /// Handles changes to the Source property.
    /// 
    private static void OnSourceChanged
        (DependencyObject aObject, DependencyPropertyChangedEventArgs aEventArgs)
    {
        ((AnimatedImage) aObject).OnSourceChanged(aEventArgs);
    }

    #endregion

    #region Dependency Properties

    /// 

    /// FrameIndex Dependency Property
    /// 
    public static readonly DependencyProperty FrameIndexProperty =
        DependencyProperty.Register(
            "FrameIndex",
            typeof (int),
            typeof (AnimatedImage),
            new UIPropertyMetadata(0, ChangingFrameIndex));

    /// 

    /// Source Dependency Property
    /// 
    public new static readonly DependencyProperty SourceProperty =
        DependencyProperty.Register(
            "Source",
            typeof (ImageSource),
            typeof (AnimatedImage),
            new FrameworkPropertyMetadata(
                null,
                FrameworkPropertyMetadataOptions.AffectsRender |
                FrameworkPropertyMetadataOptions.AffectsMeasure,
                OnSourceChanged));

    #endregion
}