Don't use fallback APIs based on OS version when running on WinAppSDK (#566)

* Don't use fallback APIs based on OS version when running on WinAppSDK

* Remove GetCurrentUapVersion function from WinAppSDK Lottie

* Separate contract version into UAP contract version and WinAppSDK contract version

---------

Co-authored-by: aborziak-ms <[email protected]>

Author: getrou

source/Lottie/Loader.cs

@@ -25,13 +25,20 @@
 
 namespace CommunityToolkit.WinUI.Lottie
 {
+#pragma warning disable SA1303 // Constants must begin with an upper case letter.
+
     /// <summary>
     /// Handles loading a composition from a Lottie file. The result of the load
     /// is a <see cref="AnimatedVisualFactory"/> that can be used to instantiate a
     /// Composition tree that will render the Lottie.
     /// </summary>
     abstract class Loader : IDisposable
     {
+        // TODO: we do not support versions above 14 in Lottie-Windows yet, only in LottieGen.
+        // Mostly this is because Lottie-Windows does not yet support custom AnimationControllers.
+        const uint c_maxUapContractVersion = 14u;
+        const uint c_maxWinAppSDKContractVersion = 14u;
+
         // Identifies the bound property names in SourceMetadata.
         static readonly Guid s_propertyBindingNamesKey = new Guid("A115C46A-254C-43E6-A3C7-9DE516C3C3C8");
 
@@ -147,7 +154,14 @@ await Task.Run(() =>
                         {
                             TranslatePropertyBindings = makeColorsBindable,
                             GenerateColorBindings = makeColorsBindable,
+#if WINAPPSDK
+                            // The WindowsAppSDK has access to the latest APIs, and should not use
+                            // fallback APIs based on which OS the app is running on. In the future
+                            // Lottie might be able to target specific WinAppSDK versions.
+                            TargetUapVersion = c_maxWinAppSDKContractVersion,
+#else
                             TargetUapVersion = GetCurrentUapVersion(),
+#endif
                         });
 
                     wincompDataRootVisual = translationResult.RootVisual;
@@ -211,6 +225,7 @@ static IReadOnlyList<Issue> ToIssues(IEnumerable<(string Code, string Descriptio
         static IReadOnlyList<Issue> ToIssues(IEnumerable<TranslationIssue> issues)
             => issues.Select(issue => new Issue(code: issue.Code, description: issue.Description)).ToArray();
 
+#if !WINAPPSDK
         /// <summary>
         /// Gets the highest UAP version supported by the current process.
         /// </summary>
@@ -228,12 +243,12 @@ static uint GetCurrentUapVersion()
                 versionToTest++;
             }
 
-            // TODO: we do not support UAP above 14 in Lottie-Windows yet, only in LottieGen.
-            versionToTest = Math.Min(versionToTest, 14);
+            versionToTest = Math.Min(versionToTest, c_maxUapContractVersion);
 
             // Query failed on versionToTest. Return the previous version.
             return versionToTest;
         }
+#endif
 
         // Specializes the Stopwatch to do just the one thing we need of it - get the time
         // elapsed since the last call then restart the Stopwatch to start measuring again.