IWiaImageFilter::FilterPreviewImage method

Filters the preview image.

Syntax

HRESULT FilterPreviewImage(
  [in] LONG      lFlags,
  [in] IWiaItem2 *pWiaChildItem2,
  [in] RECT      InputImageExtents,
  [in] IStream   *pInputStream
);

Parameters

lFlags [in]

Type: LONG

Not used. Set to 0.

pWiaChildItem2 [in]

Type: IWiaItem2*

The item that is processed.

InputImageExtents [in]

Type: RECT

The coordinates (on the physical acquisition area) of the image that the preview component caches internally.

pInputStream [in]

Type: IStream*

A pointer to the IStream interface for the cached image data that is filtered.

Return value

Type: HRESULT

If this method succeeds, it returns S_OK. Otherwise, it returns an HRESULT error code.

Remarks

Do not call this method directly from your application.

pWiaChildItem2 must be a child item of the pWiaItem2 that was passed into IWiaImageFilter::InitializeFilter.

InputImageExtents is needed because the image processing filter is responsible for cutting out the image area that pWiaChildItem2 represents from the image data passed in through pInputStream.

An application must ensure that pWiaChildItem2 has the same image format (WIA_IPA_FORMAT), resolution (WIA_IPS_XRES and WIA_IPS_YRES) and bit depth (WIA_IPA_DEPTH) as pWiaItem2 had when it was passed into GetNewPreview.

Requirements