public Stream Transfer(int pageNumber, WiaBackgroundEventLoop eventLoop, string format)
{
if (pageNumber == 1)
{
// The only downside of the common dialog is that it steals focus.
// If this is the first page, then the user has just pressed the scan button, so that's not
// an issue and we can use it and get the benefits of progress display and immediate cancellation.
ImageFile imageFile = eventLoop.GetSync(wia =>
(ImageFile)new CommonDialogClass().ShowTransfer(wia.Item, format));
if (imageFile == null)
{
return null;
}
return new MemoryStream((byte[])imageFile.FileData.get_BinaryData());
}
// For subsequent pages, we don't want to take focus in case the user has switched applications,
// so we use the custom form.
var form = formFactory.Create<FScanProgress>();
form.PageNumber = pageNumber;
form.EventLoop = eventLoop;
form.Format = format;
form.ShowDialog();
if (form.Exception != null)
{
throw form.Exception;
}
if (form.DialogResult == DialogResult.Cancel)
{
return null;
}
return form.ImageStream;
}
public Stream Transfer(int pageNumber, WiaBackgroundEventLoop eventLoop, string format)
{
// The console shouldn't spawn new forms, so use the silent transfer method.
ImageFile imageFile = eventLoop.GetSync(wia => (ImageFile)wia.Item.Transfer(format));
if (imageFile == null)
{
return null;
}
return new MemoryStream((byte[])imageFile.FileData.get_BinaryData());
}
protected override IEnumerable<IScannedImage> ScanInternal()
{
using (var eventLoop = new WiaBackgroundEventLoop(ScanProfile, ScanDevice, threadFactory))
{
bool supportsFeeder = eventLoop.GetSync(wia => WiaApi.DeviceSupportsFeeder(wia.Device));
if (ScanProfile.PaperSource != ScanSource.Glass && !supportsFeeder)
{
throw new NoFeederSupportException();
}
bool supportsDuplex = eventLoop.GetSync(wia => WiaApi.DeviceSupportsDuplex(wia.Device));
if (ScanProfile.PaperSource == ScanSource.Duplex && !supportsDuplex)
{
throw new NoDuplexSupportException();
}
int pageNumber = 1;
while (true)
{
IScannedImage image;
try
{
image = TransferImage(eventLoop, pageNumber++);
}
catch (ScanDriverException)
{
throw;
}
catch (Exception e)
{
throw new ScanDriverUnknownException(e);
}
if (image == null)
{
break;
}
yield return image;
if (ScanProfile.PaperSource == ScanSource.Glass)
{
break;
}
}
}
}
private ScannedImage TransferImage(WiaBackgroundEventLoop eventLoop, int pageNumber, out bool cancel)
{
try
{
// TODO: Use the NoUI flag uniformly
var transfer = ScanParams.NoUI ? new ConsoleWiaTransfer() : wiaTransfer;
using (var stream = transfer.Transfer(pageNumber, eventLoop, WiaApi.Formats.BMP))
{
if (stream == null)
{
cancel = true;
return null;
}
cancel = false;
using (Image output = Image.FromStream(stream))
{
using (var result = ScannedImageHelper.PostProcessStep1(output, ScanProfile))
{
if (blankDetector.ExcludePage(result, ScanProfile))
{
return null;
}
ScanBitDepth bitDepth = ScanProfile.UseNativeUI ? ScanBitDepth.C24Bit : ScanProfile.BitDepth;
var image = new ScannedImage(result, bitDepth, ScanProfile.MaxQuality, ScanProfile.Quality);
ScannedImageHelper.PostProcessStep2(image, ScanProfile);
return image;
}
}
}
}
catch (COMException e)
{
if ((uint)e.ErrorCode == WiaApi.Errors.OUT_OF_PAPER)
{
if (ScanProfile.PaperSource != ScanSource.Glass && pageNumber == 1)
{
throw new NoPagesException();
}
cancel = true;
return null;
}
else if ((uint)e.ErrorCode == WiaApi.Errors.OFFLINE)
{
throw new DeviceOfflineException();
}
else
{
throw new ScanDriverUnknownException(e);
}
}
}
protected override IEnumerable<ScannedImage> ScanInternal()
{
using (var eventLoop = new WiaBackgroundEventLoop(ScanProfile, ScanDevice, threadFactory))
{
bool supportsFeeder = eventLoop.GetSync(wia => WiaApi.DeviceSupportsFeeder(wia.Device));
if (ScanProfile.PaperSource != ScanSource.Glass && !supportsFeeder)
{
throw new NoFeederSupportException();
}
bool supportsDuplex = eventLoop.GetSync(wia => WiaApi.DeviceSupportsDuplex(wia.Device));
if (ScanProfile.PaperSource == ScanSource.Duplex && !supportsDuplex)
{
throw new NoDuplexSupportException();
}
int pageNumber = 1;
int retryCount = 0;
bool retry = false;
bool cancel = false;
do
{
ScannedImage image;
try
{
image = TransferImage(eventLoop, pageNumber, out cancel);
pageNumber++;
Debug.WriteLine("Succeeded with retry count {0}", retryCount);
retryCount = 0;
retry = false;
}
catch (ScanDriverException e)
{
if (e.InnerException is COMException && (uint)((COMException) e.InnerException).ErrorCode == 0x80004005 && retryCount < 10)
{
Thread.Sleep(1000);
retryCount += 1;
Debug.WriteLine("Retrying {0}", retryCount);
retry = true;
continue;
}
throw;
}
catch (Exception e)
{
throw new ScanDriverUnknownException(e);
}
if (image != null)
{
yield return image;
}
} while (retry || (!cancel && ScanProfile.PaperSource != ScanSource.Glass));
}
}
private ScannedImage TransferImage(WiaBackgroundEventLoop eventLoop, int pageNumber, out bool cancel)
{
try
{
var transfer = ScanParams.NoUI ? backgroundWiaTransfer : foregroundWiaTransfer;
ChaosMonkey.MaybeError(0.5, new COMException("Fail", -2147467259));
using (var stream = transfer.Transfer(pageNumber, eventLoop, WiaApi.Formats.BMP))
{
if (stream == null)
{
cancel = true;
return null;
}
cancel = false;
using (Image output = Image.FromStream(stream))
{
using (var result = ScannedImageHelper.PostProcessStep1(output, ScanProfile))
{
if (blankDetector.ExcludePage(result, ScanProfile))
{
return null;
}
ScanBitDepth bitDepth = ScanProfile.UseNativeUI ? ScanBitDepth.C24Bit : ScanProfile.BitDepth;
var image = new ScannedImage(result, bitDepth, ScanProfile.MaxQuality, ScanProfile.Quality);
image.SetThumbnail(thumbnailRenderer.RenderThumbnail(result));
ScannedImageHelper.PostProcessStep2(image, result, ScanProfile, ScanParams, pageNumber);
return image;
}
}
}
}
catch (NoPagesException)
{
if (ScanProfile.PaperSource != ScanSource.Glass && pageNumber == 1)
{
// No pages were in the feeder, so show the user an error
throw new NoPagesException();
}
// At least one page was scanned but now the feeder is empty, so exit normally
cancel = true;
return null;
}
catch (ScanDriverException)
{
throw;
}
catch (Exception e)
{
throw new ScanDriverUnknownException(e);
}
}
private IScannedImage TransferImage(WiaBackgroundEventLoop eventLoop, int pageNumber)
{
try
{
using (var stream = wiaTransfer.Transfer(pageNumber, eventLoop, WiaApi.Formats.BMP))
{
if (stream == null)
{
// User cancelled
return null;
}
using (Image output = Image.FromStream(stream))
{
double scaleFactor = 1;
if (!ScanSettings.UseNativeUI)
{
scaleFactor = ScanSettings.AfterScanScale.ToIntScaleFactor();
}
using (var result = ImageScaleHelper.ScaleImage(output, scaleFactor))
{
ScanBitDepth bitDepth = ScanSettings.UseNativeUI ? ScanBitDepth.C24Bit : ScanSettings.BitDepth;
return scannedImageFactory.Create(result, bitDepth, ScanSettings.MaxQuality);
}
}
}
}
catch (COMException e)
{
if ((uint)e.ErrorCode == WiaApi.Errors.OUT_OF_PAPER)
{
if (ScanSettings.PaperSource != ScanSource.Glass && pageNumber == 1)
{
throw new NoPagesException();
}
return null;
}
else if ((uint)e.ErrorCode == WiaApi.Errors.OFFLINE)
{
throw new DeviceOfflineException();
}
else
{
throw new ScanDriverUnknownException(e);
}
}
}
