<summary>
</summary>
<param name="bitmap"></param>
<param name="rectangle"></param>
<returns></returns>
static public WriteableBitmap _TrimingImage(WriteableBitmap bitmap , System.Windows.Int32Rect rectangle)
{
WriteableBitmap miniImage = new WriteableBitmap(rectangle.Width , rectangle.Height , 96 , 96 , System.Windows.Media.PixelFormats.Gray8 , BitmapPalettes.Gray256);
miniImage.Lock();
byte[] buffer = new byte[miniImage.PixelWidth * miniImage.PixelHeight];
bitmap.CopyPixels(rectangle , buffer , miniImage.BackBufferStride , 0);
miniImage.WritePixels(new System.Windows.Int32Rect(0 , 0 , miniImage.PixelWidth , miniImage.PixelHeight) , buffer , Convert.ToInt32(miniImage.BackBufferStride) , 0);
miniImage.Unlock();
return miniImage;
}