public static async Task<StorageFile> CacheManager(string url, Crop crop)
{
// Initialize cache folder
// Get the app's local folder.
StorageFolder localFolder = ApplicationData.Current.LocalFolder;
// Create a new subfolder in the current folder.
StorageFolder cacheFolder = await localFolder.CreateFolderAsync(Constants.CacheFolder, CreationCollisionOption.OpenIfExists);
string key = Util.GenerateKey(url);
StorageFile file = null;
try
{
file = await cacheFolder.GetFileAsync(key);
}
catch (FileNotFoundException)
{
Debug.WriteLine("File " + key + " is not cached");
byte[] bytes = await Net.Download(url);
file = await cacheFolder.CreateFileAsync(key, CreationCollisionOption.GenerateUniqueName);
if (null != crop)
{
bytes = await Transform.CropImage(bytes, crop);
}
await FileIO.WriteBytesAsync(file, bytes);
}
return file;
}
public static async Task<byte[]> CropImage(byte[] stream, Crop crop)
{
byte[] byteArray = null;
var imageStream = new MemoryStream(stream);
var fileStream = imageStream.AsRandomAccessStream();
BitmapDecoder decoder = await BitmapDecoder.CreateAsync(fileStream);
InMemoryRandomAccessStream ras = new InMemoryRandomAccessStream();
BitmapEncoder enc = await BitmapEncoder.CreateForTranscodingAsync(ras, decoder);
BitmapBounds bounds = new BitmapBounds();
bounds.Height = (uint)crop.Height;
bounds.Width = (uint)crop.Width;
bounds.X = (uint)crop.X;
bounds.Y = (uint)crop.Y;
enc.BitmapTransform.Bounds = bounds;
enc.BitmapTransform.InterpolationMode = BitmapInterpolationMode.Linear;
enc.IsThumbnailGenerated = false;
try
{
await enc.FlushAsync();
}
catch (Exception ex)
{
Debug.WriteLine("Error croping image", ex);
}
byteArray = new byte[ras.Size];
DataReader dataReader = new DataReader(ras.GetInputStreamAt(0));
await dataReader.LoadAsync((uint)ras.Size);
dataReader.ReadBytes(byteArray);
return byteArray;
}
public static async Task<StorageFile> Load(string url, Crop crop)
{
return await Loader.CacheManager(url, crop);
}