public Stream ScanOne(string deviceId, KeyValueScanOptions options, ProgressHandler progressCallback, CancellationToken cancelToken)
{
// Start the scanning process
var profileOptions = options == null ? "" : string.Join("", options.Select(kvp => $@" {kvp.Key} ""{kvp.Value.Replace("\"", "\\\"")}"""));
var allOptions = $@"--device-name=""{deviceId}"" --format=tiff --progress{profileOptions}";
var proc = StartProcess(SCANIMAGE, allOptions);
// Set up state
var procExitWaitHandle = new ManualResetEvent(false);
var outputFinishedWaitHandle = new ManualResetEvent(false);
var errorOutput = new List <string>();
var cancelled = false;
const int maxProgress = 1000;
// Set up events
proc.ErrorDataReceived += (sender, args) =>
{
if (args.Data != null)
{
var match = ProgressRegex.Match(args.Data);
if (match.Success)
{
progressCallback?.Invoke((int)float.Parse(match.Groups[1].Value) * 10, maxProgress);
}
else
{
errorOutput.Add(args.Data);
}
}
};
proc.Exited += (sender, args) => procExitWaitHandle.Set();
proc.BeginErrorReadLine();
// Read the image output into a MemoryStream off-thread
var outputStream = new MemoryStream();
Task.Factory.StartNew(() =>
{
proc.StandardOutput.BaseStream.CopyTo(outputStream);
outputStream.Seek(0, SeekOrigin.Begin);
outputFinishedWaitHandle.Set();
}, TaskCreationOptions.LongRunning);
// Wait for the process to stop (or for the user to cancel)
WaitHandle.WaitAny(new[] { procExitWaitHandle, cancelToken.WaitHandle });
if (cancelToken.IsCancellationRequested)
{
cancelled = true;
SafeStopProcess(proc, procExitWaitHandle);
}
// Ensure the image output thread has finished so we don't return an incomplete MemoryStream
outputFinishedWaitHandle.WaitOne();
if (cancelled)
{
// The user has cancelled, so we can ignore everything else
return(null);
}
if (errorOutput.Count > 0)
{
// Non-progress output to stderr indicates that the scan was not successful
var stderr = string.Join(". ", errorOutput).Trim();
ThrowDeviceError(stderr);
}
// No unexpected stderr output, so we can assume that the output stream is complete and valid
return(outputStream);
}
private KeyValueScanOptions GetOptions()
{
var saneOptions = SaneOptionCache.GetOrSet(ScanDevice.Id, () => saneWrapper.GetOptions(ScanDevice.Id));
var options = new KeyValueScanOptions(ScanProfile.KeyValueOptions ?? new KeyValueScanOptions());
bool ChooseStringOption(string name, Func <string, bool> match)
{
var opt = saneOptions.Get(name);
var choice = opt?.StringList?.FirstOrDefault(match);
if (choice != null)
{
options[name] = choice;
return(true);
}
return(false);
}
bool ChooseNumericOption(string name, decimal value)
{
var opt = saneOptions.Get(name);
if (opt?.ConstraintType == SaneConstraintType.WordList)
{
var choice = opt.WordList?.OrderBy(x => Math.Abs(x - value)).FirstOrDefault();
if (choice != null)
{
options[name] = choice.Value.ToString(CultureInfo.InvariantCulture);
return(true);
}
}
else if (opt?.ConstraintType == SaneConstraintType.Range)
{
if (value < opt.Range.Min)
{
value = opt.Range.Min;
}
if (value > opt.Range.Max)
{
value = opt.Range.Max;
}
if (opt.Range.Quant != 0)
{
var mod = (value - opt.Range.Min) % opt.Range.Quant;
if (mod != 0)
{
value = mod < opt.Range.Quant / 2 ? value - mod : value + opt.Range.Quant - mod;
}
}
options[name] = value.ToString("0.#####", CultureInfo.InvariantCulture);
return(true);
}
return(false);
}
bool IsFlatbedChoice(string choice) => choice.IndexOf("flatbed", StringComparison.InvariantCultureIgnoreCase) >= 0;
bool IsFeederChoice(string choice) => new[] { "adf", "feeder", "simplex" }.Any(x => choice.IndexOf(x, StringComparison.InvariantCultureIgnoreCase) >= 0);
bool IsDuplexChoice(string choice) => choice.IndexOf("duplex", StringComparison.InvariantCultureIgnoreCase) >= 0;
if (ScanProfile.PaperSource == ScanSource.Glass)
{
ChooseStringOption("--source", IsFlatbedChoice);
}
else if (ScanProfile.PaperSource == ScanSource.Feeder)
{
if (!ChooseStringOption("--source", x => IsFeederChoice(x) && !IsDuplexChoice(x)) &&
!ChooseStringOption("--source", IsFeederChoice) &&
!ChooseStringOption("--source", IsDuplexChoice))
{
throw new NoFeederSupportException();
}
}
else if (ScanProfile.PaperSource == ScanSource.Duplex)
{
if (!ChooseStringOption("--source", IsDuplexChoice))
{
throw new NoDuplexSupportException();
}
}
if (ScanProfile.BitDepth == ScanBitDepth.C24Bit)
{
ChooseStringOption("--mode", x => x == "Color");
ChooseNumericOption("--depth", 8);
}
else if (ScanProfile.BitDepth == ScanBitDepth.Grayscale)
{
ChooseStringOption("--mode", x => x == "Gray");
ChooseNumericOption("--depth", 8);
}
else if (ScanProfile.BitDepth == ScanBitDepth.BlackWhite)
{
if (!ChooseStringOption("--mode", x => x == "Lineart"))
{
ChooseStringOption("--mode", x => x == "Halftone");
}
ChooseNumericOption("--depth", 1);
ChooseNumericOption("--threshold", (-ScanProfile.Brightness + 1000) / 20m);
}
var pageDimens = ScanProfile.PageSize.PageDimensions() ?? ScanProfile.CustomPageSize;
if (pageDimens != null)
{
var width = pageDimens.WidthInMm();
var height = pageDimens.HeightInMm();
ChooseNumericOption("-x", width);
ChooseNumericOption("-y", height);
var maxWidth = saneOptions.Get("-l")?.Range?.Max;
var maxHeight = saneOptions.Get("-t")?.Range?.Max;
if (maxWidth != null)
{
if (ScanProfile.PageAlign == ScanHorizontalAlign.Center)
{
ChooseNumericOption("-l", (maxWidth.Value - width) / 2);
}
else if (ScanProfile.PageAlign == ScanHorizontalAlign.Right)
{
ChooseNumericOption("-l", maxWidth.Value - width);
}
else
{
ChooseNumericOption("-l", 0);
}
}
if (maxHeight != null)
{
ChooseNumericOption("-t", 0);
}
}
var dpi = ScanProfile.Resolution.ToIntDpi();
if (!ChooseNumericOption("--resolution", dpi))
{
ChooseNumericOption("--x-resolution", dpi);
ChooseNumericOption("--y-resolution", dpi);
}
return(options);
}