/// <summary>
/// Gets the device that will be used to acquire an image.
/// </summary>
private static WiaResult GetDevice(out Device device)
{
device = null;
try
{
CommonDialogClass cdc = new CommonDialogClass();
device = cdc.ShowSelectDevice(WiaDeviceType.UnspecifiedDeviceType, false, false);
if (device == null)
//Either the user cancelled OR we have no device we can use to get an image.
{
return(new WiaResult(string.Format(ERROR_MESSAGE_FORMAT,
"get the capture device",
"No device was selected")));
}
else
{
return(WiaResult.Success);
}
}
catch (COMException ce)
{
if (logger.IsDebugEnabled)
{
logger.Debug(WiaConstants.LoggingConstants.ExceptionOccurred, ce);
}
return(new WiaResult(string.Format(ERROR_MESSAGE_FORMAT,
"get the capture device",
WiaError.GetErrorMessage(ce))));
}
}
/// <summary>
/// Queries a device for the Wia Item that we will use to do the capture and
/// transfer.
/// </summary>
private static WiaResult GetCaptureItem(Device device, out Item item)
{
item = null;
try
{
//Show UI.
CommonDialogClass cdc = new CommonDialogClass();
Items items = cdc.ShowSelectItems(
device,
WiaImageIntent.UnspecifiedIntent,
WiaImageBias.MaximizeQuality,
true,
true,
false);
if (items == null || items.Count == 0)
//Cannot obtain an item to acquire the image OR the user cancelled.
{
return(new WiaResult(string.Format(ERROR_MESSAGE_FORMAT,
"get the capture item",
"No items were selected to be captured")));
}
else
{
//Wia arrays are 1-based-indexed. 1 here represents the first item.
item = items[1];
return(WiaResult.Success);
}
}
catch (COMException ce)
{
if (logger.IsDebugEnabled)
{
logger.Debug(WiaConstants.LoggingConstants.ExceptionOccurred, ce);
}
return(new WiaResult(string.Format(ERROR_MESSAGE_FORMAT,
"get the capture item",
WiaError.GetErrorMessage(ce))));
}
}
/// <summary>
/// Gets a WiaFormat object that represents an image format that the device
/// and our app both understand.
/// </summary>
private static WiaResult GetFormat(Item item, out WiaFormat format)
{
format = null;
try
{
//Devices can have supported formats and preferred formats.
string deviceFormatGuid, devicePreferredFormatGuid;
deviceFormatGuid = devicePreferredFormatGuid = null;
//Get the format information from the device
foreach (Property prop in item.Properties)
{
System.Diagnostics.Debug.WriteLine(prop.PropertyID + " - " + prop.Name + " - " + prop.get_Value());
switch (prop.PropertyID)
{
case WiaConstants.WiaProperties.FORMAT_ID:
deviceFormatGuid = (prop.get_Value() == null ? null : prop.get_Value().ToString());
break;
case WiaConstants.WiaProperties.PREFERRED_FORMAT_ID:
devicePreferredFormatGuid = (prop.get_Value() == null ? null : prop.get_Value().ToString());
break;
}
}
//We'll try and match on the preferred format first.
if (string.IsNullOrEmpty(devicePreferredFormatGuid) == false)
//Check to see if we support the preferred format.
{
format = WiaFormats.GetWiaFormat(devicePreferredFormatGuid);
if (format != null)
{
return(WiaResult.Success);
}
}
if (string.IsNullOrEmpty(deviceFormatGuid) == false)
//Check to see if we support the format
{
format = WiaFormats.GetWiaFormat(deviceFormatGuid);
if (format != null)
{
return(WiaResult.Success);
}
}
//If we've gotten here then the device does not support a format we can
//work with
return(new WiaResult(string.Format(ERROR_MESSAGE_FORMAT,
"get the image format from the device",
"No supported file format can be found on the device")));
}
catch (COMException ce)
{
if (logger.IsDebugEnabled)
{
logger.Debug(WiaConstants.LoggingConstants.ExceptionOccurred, ce);
}
return(new WiaResult(string.Format(ERROR_MESSAGE_FORMAT,
"get the image format from the device",
WiaError.GetErrorMessage(ce))));
}
}
/// <summary>
/// Transfers an image from the capture device
/// </summary>
private static WiaResult TransferImage(Item item, WiaFormat format, string outputPath, out string fileName)
{
fileName = string.Empty;
try
{
//Initiate transfer
ImageFile image = item.Transfer(format.ComGuid) as ImageFile;
if (image != null)
//Ensure something was obtained.
{
string tempFileName = string.Format("{0}.{1}", Guid.NewGuid().ToString(), format.FileExtension);
if (!outputPath.EndsWith("\\"))
{
outputPath += "\\";
}
tempFileName = outputPath + tempFileName;
image.SaveFile(tempFileName);
//An exception will be thrown if the image cannot be saved, by getting here
//we know that the save succeeded.
fileName = tempFileName;
//If the image was not saved in Jpg format then transcode it here
if (!WiaFormats.IsJpg(format.ComGuid))
{
string transcodedFileName;
WiaResult transcodeResult = TranscodeImageToJpg(fileName, out transcodedFileName);
if (!transcodeResult.Succeeded)
{
return(transcodeResult);
}
else
{
fileName = transcodedFileName;
}
}
return(WiaResult.Success);
}
else
{
return(new WiaResult(string.Format(ERROR_MESSAGE_FORMAT,
"transfer the image from the device",
"The image returned could not be cast to an ImageFile interface")));
}
}
catch (COMException ce)
{
if (logger.IsDebugEnabled)
{
logger.Debug(WiaConstants.LoggingConstants.ExceptionOccurred, ce);
}
return(new WiaResult(string.Format(ERROR_MESSAGE_FORMAT,
"transfer the image from the device",
WiaError.GetErrorMessage(ce))));
}
}