private void PhotoChooserCompleted(object sender, PhotoResult e)
{
this.showInProgress = false;
if (e.TaskResult == TaskResult.OK)
{
// Defensive. This should not happen unless maybe someone programmatically saved a 0 length image in
// the picture gallery which I am not even sure the phone API will allow.
// Since this.ocrData.PhotoStream will not accept a zero length stream we'll act defensively here.
if (e.ChosenPhoto.Length > 0)
{
Stream photoStream;
// This is the point where we have a photo available.
photoStream = e.ChosenPhoto;
// Extract the orientation flag from the photo before we do the scaling down.
// If the scaling down is performed we'll no longer have the Exif info in the photo stream.
ExifUtils exifUtils = new ExifUtils(OcrClientUtils.GetPhotoBits(photoStream));
this.ocrData.ExifOrientationFlag = exifUtils.GetOrientationFlag();
if (DoLimitPhotoSize)
{
photoStream = OcrClientUtils.LimitPhotoSize(photoStream, PhotoMaxSizeDiagonal);
}
// When setting this.ocrData.PhotoStream, the ocrData instance will notify anyone who subscribed
// to its PropertyChanged event. One of the subscribers to PropertyChanged will see that
// the PhotoStream became available and it will trigger the OCR conversion.
this.ocrData.PhotoStream = photoStream;
}
}
}
private void StartOcrConversion()
{
OcrService.RecognizeImageAsync(
HawaiiClient.HawaiiApplicationId,
OcrClientUtils.GetPhotoBits(this.ocrData.PhotoStream),
(output) =>
{
// This section defines the body of what is known as an anonymous method.
// This anonymous method is the callback method
// called on the completion of the OCR process.
// Using Dispatcher.BeginInvoke ensures that
// OnOcrCompleted is invoked on the Main UI thread.
this.Dispatcher.BeginInvoke(() => OnOcrCompleted(output));
});
this.ocrConversionStateManager.OcrConversionState = OcrConversionState.Converting;
this.Dispatcher.BeginInvoke(() => { this.mainPivot.SelectedIndex = 1; });
}