WPF Cover Flow Tutorial : Part 7 (source)

Before disclosing sources of Part 7, here a few notes.

I provide a sample ThumbnailManager, working with an IsolatedStorageFile.

public class ThumbnailManager : IThumbnailManager
{
    #region Fields
    private readonly IsolatedStorageFile store;
    #endregion
    public ThumbnailManager()
    {
        store = IsolatedStorageFile.GetUserStoreForAssembly();
    }
    public ImageSource GetThumbnail(string host, string path)
    {
        string thumbName = Path.GetFileName(path);
        if (store.GetFileNames(thumbName).Length == 0)
        {
            using (var stream = new IsolatedStorageFileStream(thumbName, FileMode.CreateNew, store))
            {
                byte[] data = GetThumbnail(path);
                stream.Write(data, 0, data.Length);
            }
        }
        using (var stream = new IsolatedStorageFileStream(thumbName, FileMode.Open, store))
        {
            var image = new BitmapImage();
            image.BeginInit();
            image.CacheOption = BitmapCacheOption.OnLoad;
            image.StreamSource = stream;
            image.EndInit();
            image.Freeze();
            return image;
        }
    }
}

I deal with host names because I am also working on an implementation dealing with many shares on the network. The GetThumbnail method just resizes pictures.

    private byte[] GetThumbnail(string path)
    {
        Image source = Image.FromFile(path);
        source = AmazonCut(source);
        int height = source.Height;
        int width = source.Width;
        int factor = (height - 1) / 250 + 1;
        int smallHeight = height / factor;
        int smallWidth = width / factor;
        Image thumb = source.GetThumbnailImage(smallWidth, smallHeight, null, IntPtr.Zero);
        using (var ms = new MemoryStream())
        {
            thumb.Save(ms, ImageFormat.Png);
            ms.Flush();
            ms.Seek(0, SeekOrigin.Begin);
            var result = new byte[ms.Length];
            ms.Read(result, 0, (int)ms.Length);
            return result;
        }
    }

For the sample videos on youtube, I downloaded many covers from amazon. That's why I need the helper function that removes the blank frame around the picture:

    private static Image AmazonCut(Image image)
    {
        if (image.Width != image.Height)
            return image;
        var bmp = new Bitmap(image);
        int size = image.Height;
        int white = System.Drawing.Color.FromKnownColor(KnownColor.White).ToArgb();
        int i = 0;
        while (i < size / 2)
        {
            if (bmp.GetPixel(i, i).ToArgb() != white)
                break;
            if (bmp.GetPixel(i, size - 1 - i).ToArgb() != white)
                break;
            if (bmp.GetPixel(size - 1 - i, i).ToArgb() != white)
                break;
            if (bmp.GetPixel(size - 1 - i, size - 1 - i).ToArgb() != white)
                break;
            i++;
        }
        if (i > 0)
        {
            i += 8;
            var zone = new Rectangle(i, i, size - 2 * i, size - 2 * i);
            return bmp.Clone(zone, System.Drawing.Imaging.PixelFormat.DontCare);
        }
        return bmp;
    }

Well this whole class is not perfect code, but it is sufficient for a demo.

If you do not know innerings of IsolatedStorage, you will find the thumbnails in a folder like C:\Documents and Settings\ded\Local Settings\Application Data\IsolatedStorage\0ypqvhod.rll\j4pydd3v.g4v\StrongName.alr3sbzvfezz2fk22sd5g0b5dxbwzr0b\AssemFiles.

Edit 2014-02-23 : Code has moved to github.