add content_total_seconds to watermark opacity expression (#2275)

CHANGELOG.md

@@ -11,6 +11,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
   - This allows specifying an expression that returns an opacity between 0.0 and 1.0
   - The expression can use:
     - `content_seconds` - the total number of seconds the frame is into the content
+    - `content_total_seconds` - the total number of seconds in the content
     - `channel_seconds` - the total number of seconds the frame is from when the channel started/activated
     - `time_of_day_seconds` - the total number of seconds the frame is since midnight
 

ErsatzTV.Core/Interfaces/Streaming/IGraphicsElement.cs

@@ -12,6 +12,7 @@ public interface IGraphicsElement
         object context,
         TimeSpan timeOfDay,
         TimeSpan contentTime,
+        TimeSpan contentTotalTime,
         TimeSpan channelTime,
         CancellationToken cancellationToken);
 }

ErsatzTV.Infrastructure/Streaming/GraphicsEngine.cs

@@ -35,6 +35,9 @@ public class GraphicsEngine(ILogger<GraphicsEngine> logger) : IGraphicsEngine
 
         try
         {
+            // `content_total_seconds` - the total number of seconds in the content
+            var contentTotalTime = context.Seek + context.Duration;
+
             while (!cancellationToken.IsCancellationRequested && frameCount < totalFrames)
             {
                 // seconds since this specific stream started
@@ -64,7 +67,13 @@ public class GraphicsEngine(ILogger<GraphicsEngine> logger) : IGraphicsEngine
                         {
                             if (!element.IsFailed)
                             {
-                                element.Draw(ctx, frameTime.TimeOfDay, contentTime, channelTime, cancellationToken);
+                                element.Draw(
+                                    ctx,
+                                    frameTime.TimeOfDay,
+                                    contentTime,
+                                    contentTotalTime,
+                                    channelTime,
+                                    cancellationToken);
                             }
                         }
                         catch (Exception ex)

ErsatzTV.Infrastructure/Streaming/WatermarkElement.cs

@@ -121,6 +121,7 @@ public class WatermarkElement : IGraphicsElement, IDisposable
         object context,
         TimeSpan timeOfDay,
         TimeSpan contentTime,
+        TimeSpan contentTotalTime,
         TimeSpan channelTime,
         CancellationToken cancellationToken)
     {
@@ -130,6 +131,7 @@ public class WatermarkElement : IGraphicsElement, IDisposable
         }
 
         _expression.Parameters["content_seconds"] = contentTime.TotalSeconds;
+        _expression.Parameters["content_total_seconds"] = contentTotalTime.TotalSeconds;
         _expression.Parameters["channel_seconds"] = channelTime.TotalSeconds;
         _expression.Parameters["time_of_day_seconds"] = timeOfDay.TotalSeconds;