adds routine to classify art into poster or banner based on aspect ratio

xbmc/video/VideoInfoScanner.cpp

@@ -1162,6 +1162,16 @@ namespace VIDEO
     }
   }
 
+  std::string CVideoInfoScanner::GetArtTypeFromSize(unsigned int width, unsigned int height)
+  {
+    std::string type = "thumb";
+    if (width*5 < height*4)
+      type = "poster";
+    else if (width*1 > height*4)
+      type = "banner";
+    return type;
+  }
+
   void CVideoInfoScanner::GetArtwork(CFileItem *pItem, const CONTENT_TYPE &content, bool bApplyToDir, bool useLocal, const std::string &actorArtPath)
   {
     CVideoInfoTag &movieDetails = *pItem->GetVideoInfoTag();

xbmc/video/VideoInfoScanner.h

@@ -102,6 +102,14 @@ namespace VIDEO
      */
     void GetArtwork(CFileItem *pItem, const CONTENT_TYPE &content, bool bApplyToDir=false, bool useLocal=true, const std::string &actorArtPath = "");
 
+    /*! \brief Retrieve the art type for an image from the given size.
+     \param width the width of the image.
+     \param height the height of the image.
+     \return "poster" if the aspect ratio is at most 4:5, "banner" if the aspect ratio
+             is at least 1:4, "thumb" otherwise.
+     */
+    static std::string GetArtTypeFromSize(unsigned int width, unsigned int height);
+
     /*! \brief Get season thumbs for a tvshow.
      All seasons (regardless of whether the user has episodes) are added to the art map.
      \param show     tvshow info tag