Only export layers where IsVisible == true

PixiEditor/Models/Controllers/BitmapManager.cs

@@ -217,7 +217,7 @@ namespace PixiEditor.Models.Controllers
 
         public WriteableBitmap GetCombinedLayersBitmap()
         {
-            return BitmapUtils.CombineLayers(ActiveDocument.Layers.ToArray(), ActiveDocument.Width, ActiveDocument.Height);
+            return BitmapUtils.CombineLayers(ActiveDocument.Layers.Where(x => x.IsVisible).ToArray(), ActiveDocument.Width, ActiveDocument.Height);
         }
 
         /// <summary>