c# - 在 windows phone 上模糊图像

Question

我正在使用 WriteableBitmapEX 库试图在 Windows Phone 8 上模糊位图图像 我试过这段代码

Uri uri = new Uri(AnyUri, UriKind.RelativeOrAbsolute);
BitmapImage img1 = new BitmapImage();
img1.UriSource = uri;
img1.CreateOptions = BitmapCreateOptions.None;
WriteableBitmap wbm = new WriteableBitmap(img1);
var wbm2 = WriteableBitmapExtensions.Convolute(wbm, WriteableBitmapExtensions.KernelGaussianBlur5x5);
PanoramaBackground.ImageSource = wbm2;

但是在该行有一个例外“对象引用未设置为对象的实例”WriteableBitmap wbm = new WriteableBitmap(img1);

为什么这不起作用？

Answer 1

这应该有效：

WriteableBitmap bitmap = BitmapFactory.New(0, 0).FromContent("RelativePathHere.png");
var blurredBitmap = WriteableBitmapExtensions.Convolute(bitmap, WriteableBitmapExtensions.KernelGaussianBlur5x5);
ImageControl.Source = blurredBitmap;

编辑

好的，看起来您是从网络上获取图像并且您遇到了异常，因为图像尚未加载。您需要订阅 ImageOpened 事件处理程序。这是代码：

Uri uri = new Uri("AbsoluteUriPath.png", UriKind.Absolute);
BitmapImage img1 = new BitmapImage(uri);
img1.CreateOptions = BitmapCreateOptions.None;
img1.ImageOpened += (s, e) =>
{
      WriteableBitmap bitmap = new WriteableBitmap(img1);
      var blurredBitmap = WriteableBitmapExtensions.Convolute(bitmap,
                WriteableBitmapExtensions.KernelGaussianBlur5x5);
            ImageControl.Source = blurredBitmap;
};