Add FilePath helper class

MapControl/Shared/FilePath.cs

@@ -0,0 +1,21 @@
+// XAML Map Control - https://github.com/ClemensFischer/XAML-Map-Control
+// © 2022 Clemens Fischer
+// Licensed under the Microsoft Public License (Ms-PL)
+
+using System;
+using System.IO;
+
+namespace MapControl
+{
+    public static class FilePath
+    {
+        public static string GetFullPath(string path)
+        {
+#if WINUI
+            return Path.GetFullPath(path, AppDomain.CurrentDomain.BaseDirectory);
+#else
+            return Path.GetFullPath(path);
+#endif
+        }
+    }
+}

MapControl/Shared/GroundOverlay.cs

@@ -174,7 +174,7 @@ namespace MapControl
 
         private static async Task<IEnumerable<ImageOverlay>> ReadGroundOverlaysFromFileAsync(string docFilePath)
         {
-            docFilePath = Path.Combine(AppDomain.CurrentDomain.BaseDirectory, docFilePath);
+            docFilePath = FilePath.GetFullPath(docFilePath);
 
             var docUri = new Uri(docFilePath);
 

MapControl/UWP/MapControl.UWP.csproj

@@ -71,6 +71,9 @@
     <Compile Include="..\Shared\EquirectangularProjection.cs">
       <Link>EquirectangularProjection.cs</Link>
     </Compile>
+    <Compile Include="..\Shared\FilePath.cs">
+      <Link>FilePath.cs</Link>
+    </Compile>
     <Compile Include="..\Shared\GeoImage.cs">
       <Link>GeoImage.cs</Link>
     </Compile>

MapControl/WinUI/GeoImage.WinUI.cs

@@ -20,8 +20,7 @@ namespace MapControl
     {
         public static async Task<Tuple<BitmapSource, Matrix>> ReadGeoTiff(string sourcePath)
         {
-            var file = await StorageFile.GetFileFromPathAsync(
-                Path.Combine(AppDomain.CurrentDomain.BaseDirectory, sourcePath));
+            var file = await StorageFile.GetFileFromPathAsync(FilePath.GetFullPath(sourcePath));
 
             using (var stream = await file.OpenReadAsync())
             {

MapControl/WinUI/ImageLoader.WinUI.cs

@@ -50,7 +50,7 @@ namespace MapControl
         {
             ImageSource image = null;
 
-            path = Path.Combine(AppDomain.CurrentDomain.BaseDirectory, path);
+            path = FilePath.GetFullPath(path);
 
             if (File.Exists(path))
             {