private async Task <IRandomAccessStream> ResizeJpegStreamAsync(int maxPixelDimension, int percentQuality, IRandomAccessStream input)
{
var decoder = await BitmapDecoder.CreateAsync(input);
int targetHeight;
int targetWidth;
MvxPictureDimensionHelper.TargetWidthAndHeight(maxPixelDimension, (int)decoder.PixelWidth, (int)decoder.PixelHeight, out targetWidth, out targetHeight);
var transform = new BitmapTransform()
{
ScaledHeight = (uint)targetHeight, ScaledWidth = (uint)targetWidth
};
var pixelData = await decoder.GetPixelDataAsync(
BitmapPixelFormat.Rgba8,
BitmapAlphaMode.Straight,
transform,
ExifOrientationMode.RespectExifOrientation,
ColorManagementMode.DoNotColorManage);
var destinationStream = new InMemoryRandomAccessStream();
var bitmapPropertiesSet = new BitmapPropertySet();
bitmapPropertiesSet.Add("ImageQuality", new BitmapTypedValue(((double)percentQuality) / 100.0, PropertyType.Single));
var encoder = await BitmapEncoder.CreateAsync(BitmapEncoder.JpegEncoderId, destinationStream, bitmapPropertiesSet);
encoder.SetPixelData(BitmapPixelFormat.Rgba8, BitmapAlphaMode.Premultiplied, (uint)targetWidth, (uint)targetHeight, decoder.DpiX, decoder.DpiY, pixelData.DetachPixelData());
await encoder.FlushAsync();
destinationStream.Seek(0L);
return(destinationStream);
}
public void ChoosePictureFromLibrary(int maxPixelDimension, int percentQuality, Action <Stream, string> pictureAvailable, Action assumeCancelled)
{
var filePicker = new OpenFileDialog();
filePicker.Filter = "Image Files (*.jpg,*.jpeg,*.gif,*.png)|*.jpg;*.jpeg;*.gif;*.png";
filePicker.Multiselect = false;
if (filePicker.ShowDialog() == true)
{
try
{
var bm = new Bitmap(filePicker.FileName);
if (bm != null)
{
int targetWidth;
int targetHeight;
MvxPictureDimensionHelper.TargetWidthAndHeight(maxPixelDimension, bm.Width, bm.Height, out targetWidth, out targetHeight);
var transformBM = new TransformedBitmap(ConvertBitmapInBitmapSource(bm), new ScaleTransform(targetWidth / (double)bm.Width, targetHeight / (double)bm.Height));
var encoder = GetBitmapEncoder(filePicker.FileName, percentQuality);
if (encoder == null)
{
throw new NotSupportedException("The image file is invalid. Please, select a jpg, jpeg, gif, png or tiff file.");
}
MemoryStream stream = new MemoryStream();
encoder.Frames.Add(BitmapFrame.Create(transformBM));
encoder.Save(stream);
stream.Position = 0;
pictureAvailable(stream, filePicker.FileName);
}
}
catch (ArgumentException)
{
assumeCancelled();
}
}
else
{
assumeCancelled();
}
}
private void ResizeJpegStream(int maxPixelDimension, int percentQuality, Stream input, Action <Stream> success)
{
var bitmap = new BitmapImage();
bitmap.SetSource(input);
var writeable = new WriteableBitmap(bitmap);
int targetHeight;
int targetWidth;
MvxPictureDimensionHelper.TargetWidthAndHeight(maxPixelDimension, writeable.PixelWidth, writeable.PixelHeight, out targetWidth, out targetHeight);
// not - important - we do *not* use using here - disposing of memoryStream is someone else's problem
var memoryStream = new MemoryStream();
writeable.SaveJpeg(memoryStream, targetWidth, targetHeight, 0, percentQuality);
memoryStream.Seek(0L, SeekOrigin.Begin);
success(memoryStream);
}
private async Task<IRandomAccessStream> ResizeJpegStreamAsyncRubbish(int maxPixelDimension, int percentQuality, IRandomAccessStream input)
{
BitmapDecoder decoder = await BitmapDecoder.CreateAsync(input);
// create a new stream and encoder for the new image
var ras = new InMemoryRandomAccessStream();
var enc = await BitmapEncoder.CreateForTranscodingAsync(ras, decoder);
int targetHeight;
int targetWidth;
MvxPictureDimensionHelper.TargetWidthAndHeight(maxPixelDimension, (int)decoder.PixelWidth, (int)decoder.PixelHeight, out targetWidth, out targetHeight);
enc.BitmapTransform.ScaledHeight = (uint)targetHeight;
enc.BitmapTransform.ScaledWidth = (uint)targetWidth;
// write out to the stream
await enc.FlushAsync();
return ras;
}