private static ObjectAnimationUsingKeyFrames GetAnimation(Image imageControl, BitmapSource source)
{
var cacheEntry = AnimationCache.Get(source);
if (cacheEntry == null)
{
var decoder = GetDecoder(source, imageControl, out GifFile gifMetadata) as GifBitmapDecoder;
if (decoder != null && decoder.Frames.Count > 1)
{
var fullSize = GetFullSize(decoder, gifMetadata);
int index = 0;
var keyFrames = new ObjectKeyFrameCollection();
var totalDuration = TimeSpan.Zero;
BitmapSource baseFrame = null;
foreach (var rawFrame in decoder.Frames)
{
var metadata = GetFrameMetadata(decoder, gifMetadata, index);
var frame = MakeFrame(fullSize, rawFrame, metadata, baseFrame);
var keyFrame = new DiscreteObjectKeyFrame(frame, totalDuration);
keyFrames.Add(keyFrame);
totalDuration += metadata.Delay;
switch (metadata.DisposalMethod)
{
case FrameDisposalMethod.None:
case FrameDisposalMethod.DoNotDispose:
baseFrame = frame;
break;
case FrameDisposalMethod.RestoreBackground:
if (IsFullFrame(metadata, fullSize))
{
baseFrame = null;
}
else
{
baseFrame = ClearArea(frame, metadata);
}
break;
case FrameDisposalMethod.RestorePrevious:
// Reuse same base frame
break;
}
index++;
}
int repeatCount = GetRepeatCountFromMetadata(decoder, gifMetadata);
cacheEntry = new AnimationCacheEntry(keyFrames, totalDuration, repeatCount);
AnimationCache.Add(source, cacheEntry);
}
}
if (cacheEntry != null)
{
var animation = new ObjectAnimationUsingKeyFrames
{
KeyFrames = cacheEntry.KeyFrames,
Duration = cacheEntry.Duration,
RepeatBehavior = GetActualRepeatBehavior(imageControl, cacheEntry.RepeatCountFromMetadata),
SpeedRatio = GetActualSpeedRatio(imageControl, cacheEntry.Duration)
};
AnimationCache.AddControlForSource(source, imageControl);
return(animation);
}
return(null);
}
public static void Add(ImageSource source, AnimationCacheEntry entry)
{
var key = new CacheKey(source);
_animationCache[key] = entry;
}