use gif watermark metadata in graphics engine (#2465)

CHANGELOG.md

@@ -77,6 +77,10 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 - Use NVIDIA NvEnc API to detect encoder capability instead of heuristic based on GPU model/architecture
 - Use NVIDIA Cuvid API to detect decoder capability instead of heuristic based on GPU model/architecture
 - Fix filler expression not being respected when using a playlist as filler
+- Use "repeat count" metadata from animated GIFs in graphics engine (i.e. watermarks)
+  - GIFs flagged to loop forever will loop forever
+  - GIFs with a specific loop count will loop the specified number of times and then hold the final frame
+    - Note that looping is relative to the start of the content, so this works best with permanent watermarks
 
 ### Changed
 - Filler presets: use separate text fields for `hours`, `minutes` and `seconds` duration

ErsatzTV.Application/Configuration/Commands/UpdateLibraryRefreshIntervalHandler.cs

@@ -26,6 +26,6 @@ public class UpdateLibraryRefreshIntervalHandler :
         Optional(request.LibraryRefreshInterval)
             .Where(lri => lri is >= 0 and < 1_000_000)
             .Map(_ => Unit.Default)
-            .ToValidation<BaseError>("Library refresh interval must be zero or greated")
+            .ToValidation<BaseError>("Library refresh interval must be zero or greater")
             .AsTask();
 }

ErsatzTV.Infrastructure/Streaming/Graphics/Image/ImageElementBase.cs

@@ -19,6 +19,7 @@ public abstract class ImageElementBase : GraphicsElement, IDisposable
     private readonly List<double> _frameDelays = [];
     private readonly List<SKBitmap> _scaledFrames = [];
     private double _animatedDurationSeconds;
+    private ushort _repeatCount;
 
     private Image _sourceImage;
 
@@ -83,6 +84,11 @@ public abstract class ImageElementBase : GraphicsElement, IDisposable
             horizontalMargin,
             verticalMargin);
 
+        if (_sourceImage.Metadata.DecodedImageFormat == GifFormat.Instance)
+        {
+            _repeatCount = _sourceImage.Metadata.GetFormatMetadata(GifFormat.Instance).RepeatCount;
+        }
+
         _animatedDurationSeconds = 0;
 
         for (var i = 0; i < _sourceImage.Frames.Count; i++)
@@ -161,6 +167,11 @@ public abstract class ImageElementBase : GraphicsElement, IDisposable
             return _scaledFrames[0];
         }
 
+        if (_repeatCount > 0 && timestamp.TotalSeconds >= _animatedDurationSeconds * _repeatCount)
+        {
+            return _scaledFrames.Last();
+        }
+
         double currentTime = timestamp.TotalSeconds % _animatedDurationSeconds;
 
         double frameTime = 0;