public override void ViewDidLoad()
{
if (Request != null)
{
Request = new VNRecognizeTextRequest(RecognizeTextHandler);
}
base.ViewDidLoad();
}
public void DidFinish(VNDocumentCameraViewController controller, VNDocumentCameraScan scan)
{
var pageCount = (int)scan.PageCount;
var allItems = new List <List <string> >();
for (int i = 0; i < pageCount; i++)
{
var image = scan.GetImage(nuint.Parse(i.ToString()));
var imageRequestHandler = new VNImageRequestHandler(image.CGImage, options: new NSDictionary());
var textRequest = new VNRecognizeTextRequest(new VNRequestCompletionHandler((request, error) =>
{
var results = request.GetResults <VNRecognizedTextObservation>();
foreach (var result in results)
{
var items = new List <string>();
foreach (var candidate in result.TopCandidates(100))
{
items.Add(candidate.String);
}
allItems.Add(items);
}
Device.BeginInvokeOnMainThread(() =>
{
_page.LoadRecognizedTextItems(allItems);
DismissViewController(true, null);
});
}));
switch (_page.TextRecognitionLevel)
{
case TextRecognitionLevelEnum.Accurate:
textRequest.RecognitionLevel = VNRequestTextRecognitionLevel.Accurate;
break;
case TextRecognitionLevelEnum.Fast:
textRequest.RecognitionLevel = VNRequestTextRecognitionLevel.Fast;
break;
default:
break;
}
textRequest.UsesLanguageCorrection = true;
DispatchQueue.DefaultGlobalQueue.DispatchAsync(() =>
{
imageRequestHandler.Perform(new VNRequest[] { textRequest }, out NSError error);
});
}
}
public Task <ScanResult> ProcessImage(Stream bitmapStream)
{
var imageData = NSData.FromStream(bitmapStream);
var image = UIImage.LoadFromData(imageData);
var v = new VNImageOptions();
if (image.CGImage == null)
{
throw new Exception("No image");
}
// TODO: Find a way to make orientation foolproof
// (Probably convert stream to UIImage which has orientation encoded...)
var requestHandler =
new VNImageRequestHandler(image.CGImage, v);
var completionSource = new TaskCompletionSource <ScanResult>();
var request = new VNRecognizeTextRequest((vnRequest, error) =>
{
var results = vnRequest.GetResults <VNRecognizedTextObservation>();
var scanResult = new ScanResult();
foreach (var textObservation in results)
{
var candidate = textObservation.TopCandidates(1).FirstOrDefault();
if (candidate != null)
{
scanResult.Add(GetBlock(candidate, textObservation));
}
}
completionSource.TrySetResult(scanResult);
});
requestHandler.Perform(new VNRequest[] { request }, out var nsError);
// ReSharper disable once ConstantConditionalAccessQualifier
if (!string.IsNullOrEmpty(nsError?.Description))
{
throw new Exception(nsError.Description);
}
return(completionSource.Task);
}
