Para este ejemplo en particular utilice el ImageTools.
Paso 1 - Descargar/escribir la librería para la de-codificación de imágenes GIF.
Paso 2 - Agregar las referencias al proyecto
Paso 3 - Obtener el stream de la imagen
Esto puede ser desde una URL, desde el Isolated Storage, o desde un Recurso de aplicación, para este ejemplo se muestran tanto el de recurso de aplicación como el de URI de internet.
private static WebClient proxy;
public delegate void ImageReceivedDelegate(Stream stream);
public static event ImageReceivedDelegate ImageReceived;
/// <summary>
/// Get a Image Stream from a resource
/// </summary>
/// <param name="filename">File Name</param>
/// <param name="imagelocation">Image Path</param>
/// <returns></returns>
public static Stream GetImageStream(string filename, string imagelocation)
{
StreamResourceInfo imageResource = Application.GetResourceStream(new Uri(imagelocation + filename, UriKind.Relative));
return imageResource.Stream;
}
/// <summary>
/// Get a Image stream from a internet URI
/// </summary>
/// <param name="uri"></param>
public static void GetImageStream(string uri)
{
try {
proxy = new WebClient();
proxy.OpenReadCompleted += new OpenReadCompletedEventHandler(proxy_OpenReadCompleted);
proxy.OpenReadAsync(new Uri(uri));
}
catch {
}
}
/// <summary>
/// Event Handler to process the open_read completed event, this bubble the event using a delegate
/// to throw out the file stream
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private static void proxy_OpenReadCompleted(object sender, OpenReadCompletedEventArgs e)
{
proxy = null;
if (ImageReceived != null)
{
ImageReceived(e.Result);
}
}
Paso 4 - Decodificar la imagen
En el constructor o en un evento de carga de la pagina, asociar un manejador del evento para ImageReceived.
ImageHandler.ImageReceived += new ImageHandler.ImageReceivedDelegate(ImageHandler_ImageReceived);
Implementar el manejador del evento
void ImageHandler_ImageReceived(System.IO.Stream stream)
{
try
{
var img = new ImageTools.ExtendedImage ();
var dec = new ImageTools.IO.Gif.GifDecoder();
dec.Decode(img, stream);
/*TODO*/
}
catch (Exception ex)
{
}
finally {
stream.Close();
}
}
Paso 5 - Convertir la imagen en un bitmap, usando el WritableBitmap
/// <summary>
/// Converts a ImageBase into a WritableBitmap, usable when we need to convert images between formats
/// </summary>
/// <param name="image"></param>
/// <returns></returns>
public static WriteableBitmap ToBitmap(ImageTools.ImageBase image)
{
ImageTools.ImageBase temp = image;
var bitmap = new WriteableBitmap(image.PixelWidth, image.PixelHeight);
byte[] pixels = temp.Pixels;
int[] raster = bitmap.Pixels;
Buffer.BlockCopy(pixels, 0, raster, 0, pixels.Length);
for (int i = 0; i < raster.Length; i++)
{
int abgr = raster[i];
int a = (abgr >> 24) & 0xff;
float m = a / 255f;
int argb = a << 24 |
(int)((abgr & 0xff) * m) << 16 |
(int)(((abgr >> 8) & 0xff) * m) << 8 |
(int)(((abgr >> 16) & 0xff) * m);
raster[i] = argb;
}
bitmap.Invalidate();
return bitmap;
}
Paso 6 - Enlazar el bitmap a un control de imagen
void ImageHandler_ImageReceived(System.IO.Stream stream)
{
try
{
var img = new ImageTools.ExtendedImage ();
var dec = new ImageTools.IO.Gif.GifDecoder();
dec.Decode(img, stream);
image1.Source = ToBitmap(img);
}
catch (Exception ex)
{
}
finally {
stream.Close();
}
}
