我有允许用户使用文件选择器选择图像的代码，并将图像转换为字节数组，以便可以对其进行序列化。在查看图像集合时，如果我的图像太多，则该应用程序将崩溃并无法加载。当我使用Visual Studio进行调试时，它可以正常运行，但需要很长时间才能加载图像。我相信它会超时，因为它需要很长时间才能加载。获取存储文件后。如何降低BitmapImage的质量，以便在序列化时不需要花费很长时间加载？
private async void AddPic_OnClick(object sender, RoutedEventArgs e)
{
ImagePath = string.Empty;
FileOpenPicker openPicker = new FileOpenPicker();
openPicker.ViewMode = PickerViewMode.Thumbnail;
openPicker.SuggestedStartLocation = PickerLocationId.PicturesLibrary;
openPicker.FileTypeFilter.Clear();
openPicker.FileTypeFilter.Add(".bmp");
openPicker.FileTypeFilter.Add(".jpg");
openPicker.FileTypeFilter.Add(".jpeg");
openPicker.FileTypeFilter.Add(".png");
// Launch file open picker and caller app is suspended and may be terminated
var file = await openPicker.PickSingleFileAsync();
if (file != null)
{
var stream = await file.OpenAsync(Windows.Storage.FileAccessMode.Read);
var image = new BitmapImage();
image.SetSource(stream);
xamlimg.Source = image;
_myClass.ImageBytes = await App.DataModel.GetBytesAsync(file);
}
}
其他班级详细信息：
public BitmapImage Image
{
get
{
if (ImageBytes == null)
return null;
if (_Image == null)
_Image = new BitmapImage();
using (var stream = new InMemoryRandomAccessStream())
{
stream.WriteAsync(ImageBytes.AsBuffer()).Completed = (i, j) =>
{
stream.Seek(0);
_Image.SetSource(stream);
};
}
return _Image;
}
}
[JsonProperty]
public byte[] ImageBytes { get; set; }
public async Task<byte[]> GetBytesAsync(StorageFile file)
{
byte[] fileBytes = null;
if (file == null) return null;
using (var stream = await file.OpenReadAsync())
{
fileBytes = new byte[stream.Size];
using (var reader = new DataReader(stream))
{
await reader.LoadAsync((uint) stream.Size);
reader.ReadBytes(fileBytes);
}
}
return fileBytes;
}
您可以对其进行解码并将其缩放为更小。因此，一旦获得了文件选择器的结果，就可以执行以下操作：
using (IRandomAccessStream fileStream = await result.OpenAsync(FileAccessMode.Read))
{
BitmapDecoder decoder = await BitmapDecoder.CreateAsync(fileStream);
using (var encoderStream = new InMemoryRandomAccessStream())
{
BitmapEncoder encoder = await BitmapEncoder.CreateForTranscodingAsync(encoderStream, decoder);
var newHeight = decoder.PixelHeight / 2;
var newWidth = decoder.PixelWidth / 2;
encoder.BitmapTransform.ScaledHeight = newHeight;
encoder.BitmapTransform.ScaledWidth = newWidth;
await encoder.FlushAsync();
byte[] pixels = new byte[newWidth * newHeight * 4];
await encoderStream.ReadAsync(pixels.AsBuffer(), (uint)pixels.Length, InputStreamOptions.None);
}
字节数组像素然后应较小以进行序列化，但图像质量较差。
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