本机Windows 8图像API

Question

我试图实现一个Windows 8应用程序来更改锁定屏幕图像。将映像写入独立存储的代码的一部分如下：

private async void photoChooserTask_Completed(object sender, PhotoResult e)
        {
            if (e.TaskResult == TaskResult.OK)
            {
                using (IsolatedStorageFile store = IsolatedStorageFile.GetUserStoreForApplication())
                {
                    store.Remove();
                }
                BitmapImage bi = new BitmapImage();
                bi.SetSource(e.ChosenPhoto);
                WriteableBitmap wb = new WriteableBitmap(bi);
                byte[] buffer = null;
                using (var ms = new System.IO.MemoryStream())
                {
                    int quality = 80;
                    e.ChosenPhoto.Seek(0, SeekOrigin.Begin);

                    // TODO: Crop or rotate here if needed

                    wb.SaveJpeg(ms, wb.PixelWidth, wb.PixelHeight, 0, quality);
                    buffer = ms.ToArray();
                }
                var isoFolder = Windows.Storage.ApplicationData.Current.LocalFolder;
                var nextImageName = Guid.NewGuid() + ".jpg";
                var newImageFile = await isoFolder.CreateFileAsync(nextImageName, Windows.Storage.CreationCollisionOption.FailIfExists);
                using (var wfs = await newImageFile.OpenStreamForWriteAsync())
                {
                    wfs.Write(buffer, 0, buffer.Length);
                }
                Windows.Phone.System.UserProfile.LockScreen.SetImageUri(new Uri("ms-appdata:///Local/" + nextImageName, UriKind.Absolute));
                MessageBox.Show("You have successfully set a new background");
            }
        }

在代码的中间，您可以看到以下注释：

// TODO: Crop or rotate here if needed

我的问题是：

本地图像裁剪的代码是什么？(例如，您通过本机Windows锁定屏幕设置为锁定屏幕选择照片时所看到的照片)

Answer 1

如果使用PhotoChooserTask，可以将所需的值设置为PixelHeight和PixelWidth属性，它将自动显示本机图像裁剪页面：

photoChooser.PixelHeight = 500;
photoChooser.PixelWidth = 500;

但是，无法从其他地方打开它(即没有PhotoChooseTask)。