Create covers in a task

Vocaluxe/Base/CCover.cs

@@ -19,6 +19,7 @@ using System;
 using System.Collections.Generic;
 using System.Drawing;
 using System.IO;
+using System.Threading.Tasks;
 using VocaluxeLib;
 using VocaluxeLib.Draw;
 using VocaluxeLib.Songs;
@@ -101,12 +102,15 @@ namespace Vocaluxe.Base
         public static CTextureRef GenerateCover(string text, ESongSorting sorting, CCategory category)
         {
             CSong firstSong = category.GetSong(0);
-            Bitmap coverBmp = _NoCoverThemes[_SongSortingToType(sorting)].GetCover(text, firstSong != null ? Path.Combine(firstSong.Folder, firstSong.CoverFileName) : null);
-            if (coverBmp == null)
-                coverBmp = _NoCoverThemes[_DefaultTypeName].GetCover(text, firstSong != null ? Path.Combine(firstSong.Folder, firstSong.CoverFileName) : null);
-            if (coverBmp == null)
-                return NoCover;
-            CTextureRef texture = CDraw.AddTexture(coverBmp);
+            CTextureRef texture = CDraw.CopyTexture(NoCover);
+            Task.Factory.StartNew(() =>
+                {
+                    Bitmap coverBmp = _NoCoverThemes[_SongSortingToType(sorting)].GetCover(text, firstSong != null ? Path.Combine(firstSong.Folder, firstSong.CoverFileName) : null);
+                    if (coverBmp == null)
+                        coverBmp = _NoCoverThemes[_DefaultTypeName].GetCover(text, firstSong != null ? Path.Combine(firstSong.Folder, firstSong.CoverFileName) : null);
+                    if (coverBmp != null)
+                        CDraw.EnqueueTextureUpdate(texture, coverBmp);
+                });
             lock (_Covers)
             {
                 _Covers.Add(text, texture);

Vocaluxe/Base/CDraw.cs

@@ -216,7 +216,8 @@ namespace Vocaluxe.Base
 
         /// <summary>
         ///     Requests updating a texture from a bitmap<br />
-        ///     Use this if you add textures from another thread or don't need it immediatelly
+        ///     Use this if you add textures from another thread or don't need it immediatelly <br />
+        ///     Bitmap is freed after use
         /// </summary>
         /// <param name="textureRef">Reference to the texture to update</param>
         /// <param name="bmp"></param>