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IWiaDevMgr::GetImageDlg method

The IWiaDevMgr::GetImageDlg method displays one or more dialog boxes that enable a user to acquire an image from a Windows Image Acquisition (WIA) device and write the image to a specified file. This method combines the functionality of IWiaDevMgr::SelectDeviceDlg to completely encapsulate image acquisition within a single API call.

Syntax


HRESULT GetImageDlg(
  [in]       HWND hwndParent,
  [in]       LONG lDeviceType,
  [in]       LONG lFlags,
  [in]       LONG lIntent,
  [in]       IWiaItem *pItemRoot,
  [in]       BSTR bstrFilename,
  [in, out]  GUID *pguidFormat
);

Parameters

hwndParent [in]

Type: HWND

Handle of the window that owns the Get Image dialog box.

lDeviceType [in]

Type: LONG

Specifies which type of WIA device to use. Is set to StiDeviceTypeDefault, StiDeviceTypeScanner, or StiDeviceTypeDigitalCamera.

lFlags [in]

Type: LONG

Specifies dialog box behavior. Can be set to the following values:

FlagMeaning
0Default behavior.
WIA_SELECT_DEVICE_NODEFAULTForce this method to display the Select Device dialog box. For more information, see the Remarks section of this reference page.
WIA_DEVICE_DIALOG_SINGLE_IMAGERestrict image selection to a single image in the device image acquisition dialog box.
WIA_DEVICE_DIALOG_USE_COMMON_UIUse the system UI, if available, rather than the vendor-supplied UI. If the system UI is not available, the vendor UI is used. If neither UI is available, the function returns E_NOTIMPL.

 

lIntent [in]

Type: LONG

Specifies what type of data the image is intended to represent. For a list of image intent values, see Image Intent Constants.

pItemRoot [in]

Type: IWiaItem*

Pointer to the interface of the hierarchical tree of IWiaItem objects returned by IWiaDevMgr::CreateDevice.

bstrFilename [in]

Type: BSTR

Specifies the name of the file to which the image data is written.

pguidFormat [in, out]

Type: GUID*

On input, contains a pointer to a GUID that specifies the format to use. On output, holds the format used. Pass IID_NULL to use the default format.

Return value

Type: HRESULT

IWiaDevMgr::GetImageDlg returns S_FALSE if the user cancels the device selection or image acquisition dialog boxes, WIA_S_NO_DEVICE_AVAILABLE if no WIA device is currently available, E_NOTIMPL if no UI is available, and S_OK if the data is transferred successfully.

IWiaDevMgr::GetImageDlg returns a value specified in Error Codes, or a standard COM error if it fails for any reason other than those specified.

Remarks

Invoking this method displays a dialog box that enables users to acquire images. It can also display the Select Device dialog box created by the IWiaDevMgr::SelectDeviceDlg method.

If the application passes NULL for the value of the pItemRoot parameter, IWiaDevMgr::GetImageDlg displays the Select Device dialog box that lets the user select the WIA input device. If the application specifies a WIA input device by passing a pointer to the device's item tree through the pItemRoot parameter, IWiaDevMgr::GetImageDlg does not display the Select Device dialog box. Instead, it will use the specified input device to acquire the image.

When using the Select Device dialog box, applications can specify types of WIA input devices. To do so, they must set the pItemRoot parameter to NULL and pass the appropriate constants through the lDeviceType parameter. If more than one device of the specified type is present, the IWiaDevMgr::GetImageDlg displays the Select Device dialog box to let the user select which device will be used.

If IWiaDevMgr::GetImageDlg finds only one matching device, it will not display the Select Device dialog box. Instead, it will select the matching device. You can override this behavior and force IWiaDevMgr::GetImageDlg to display the Select Device dialog box by passing WIA_SELECT_DEVICE_NODEFAULT as the value for the lFlags parameter.

It is recommended that applications make device and image selection available through a menu item named From scanner or camera on the File menu.

The dialog must have sufficient rights to the folder for bstrFilename that it can save the file with a unique file name. The folder should also be protected with an access control list (ACL) because it contains user data.

Requirements

Minimum supported client

Windows 2000 Professional, Windows XP [desktop apps only]

Minimum supported server

Windows Server 2003 [desktop apps only]

Header

Wia.h

Library

Wiaguid.lib

DLL

Wiaservc.dll

 

 

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