public static UIImage AnimateGif(CGImageSource source, nfloat scale, CGImageThumbnailOptions options, TaskParameter parameters)
{
if (source == null)
{
return(null);
}
var frameCount = source.ImageCount;
// no need to animate, fail safe.
if (frameCount <= 1)
{
using (var imageRef = source.CreateThumbnail(0, options))
{
return(new UIImage(imageRef, scale, UIImageOrientation.Up));
}
}
var frames = GetFrames(source, options);
var delays = GetDelays(source);
var totalDuration = delays.Sum();
var adjustedFrames = AdjustFramesToSpoofDurations(frames, scale, delays, totalDuration);
return(UIImage.CreateAnimatedImage(adjustedFrames.ToArray(), totalDuration / 100.0));
}
private static List <CoreGraphics.CGImage> GetFrames(CGImageSource source, CGImageThumbnailOptions options)
{
var retval = new List <CoreGraphics.CGImage>();
for (int i = 0; i < source?.ImageCount; i++)
{
var frameImage = source.CreateThumbnail(i, options);
retval.Add(frameImage);
}
return(retval);
}
static CoreGraphics.CGImage[] GetFrames(CGImageSource source, CGImageThumbnailOptions options)
{
var retval = new CoreGraphics.CGImage[source.ImageCount];
for (int i = 0; i < source.ImageCount; i++)
{
var frameImage = source.CreateThumbnail(i, options);
retval[i] = frameImage;
}
return(retval);
}
static CGImage CreateThumbnail (CGImageSource source, int maxPixelSize, CancellationToken token)
{
token.ThrowIfCancellationRequested ();
return source.CreateThumbnail (0, new CGImageThumbnailOptions {
CreateThumbnailWithTransform = true,
CreateThumbnailFromImageAlways = true,
MaxPixelSize = maxPixelSize,
ShouldCache = false
});
}