Converting a Text Ink Object to Ink

Implementation of converting from a text ink object (tInk) to ink.

To convert from a text ink object to ink

1. Use the IPersistStream interface to write the contents of the text ink object out to a stream. The text ink object uses ink serialized format to write to the steam.
2. Read the contents of the stream into a BYTE array.
3. Use the InkDisp object's Load method to load the contents of the stream into the InkDisp object.

Text Ink Object to Ink Object Example

The following code fragment converts a text ink object to ink.

First, the code obtains a text ink object.

/* Create a variable to hold the text ink object */
CComPtr<IInkObject *> spITextInk;

/* Obtain the text ink object */

Then, the code creates a pointer for the stream that holds the contents of the text ink object.

// Create a Stream pointer to hold the saved object
CComPtr<IStream *> spStream = NULL; 

Then, the code obtains the IPersistStream interface from the text ink object.

// Declare the IPersistStream to be used for retrieving the saved data from the text ink
CComPtr<IPersistStream *> spIPersistStream = NULL;
// Get the actual IPersistStream interface off of the TextInk
HRESULT hr = pITextInk->QueryInterface(IID_IPersistStream, (void **)&spIPersistStream);
ASSERT(SUCCEEDED(hr) && spIPersistStream);

Then, the code uses the IPersistStream interface to save the contents of the text ink object to the stream.

if( SUCCEEDED(hr) && pIPersistStream )
{
    // Create the stream 
    if( SUCCEEDED(hr=CreateStreamOnHGlobal(NULL, TRUE, &spStream)) && spStream )
    {
        // Save the TextInk through IPersistStream Interface to the IStream
        hr = spIPersistStream->Save(spStream, FALSE);
    }
}

Then, the code creates an InkCollector object, creates an InkDisp object for the InkCollector, attaches the InkCollector to the application window, and enables ink collection on the InkCollector.

// Now create an InkCollector object along with InkDisp Object
if( SUCCEEDED(hr) && spStream)
{
    CComPtr<IInkCollector *> spIInkCollector;
    CComPtr<IInkDisp *> spIInkDisp = NULL;

    // Create the InkCollector object.
    hr = CoCreateInstance(CLSID_InkCollector, 
        NULL, CLSCTX_INPROC_SERVER, 
        IID_IInkCollector, 
        (void **) &spIInkCollector);
    if (FAILED(hr)) 
        return -1;

    // Get a pointer to the Ink object
    hr = spIInkCollector->get_Ink(&spIInkDisp);
    if (FAILED(hr)) 
        return -1;

    // Tell InkCollector the window to collect ink in
    hr = spIInkCollector->put_hWnd((long)hwnd);
    if (FAILED(hr)) 
        return -1;

    // Enable ink input in the window
    hr = spIInkCollector->put_Enabled(VARIANT_TRUE);
    if (FAILED(hr)) 
        return -1;

Then, the code retrieves the size of the stream and creates a safe array to hold the contents of the stream.

    // Now create a variant data type based on the IStream data
    const LARGE_INTEGER li0 = {0, 0};
    ULARGE_INTEGER uli = {0,0};

    // Find the size of the stream
    hr = spStream->Seek(li0, STREAM_SEEK_END, &uli);
    ASSERT(0 == uli.HighPart);
    DWORD dwSize = uli.LowPart;

    // Set uli to point to the beginning of the stream.
    hr=spStream->Seek(li0, STREAM_SEEK_SET, &uli);
    ASSERT(SUCCEEDED(hr));

    // Create a safe array to hold the stream contents
    if( SUCCEEDED(hr) )
    {
        VARIANT vtData;
        VariantInit(&vtData);
        vtData.vt = VT_ARRAY | VT_UI1;

        vtData.parray = ::SafeArrayCreateVector(VT_UI1, 0, dwSize);
        if (vtData.parray)
        {

Finally, the code accesses the safe array and uses the InkDisp object's Load method to load the ink from the array.

            DWORD dwRead = 0;
            LPBYTE pbData = NULL; 

            if (SUCCEEDED(::SafeArrayAccessData(vtData.parray, (void**)&pbData)))
            {
                // Read the data from the stream to the varian data and load that into an InkDisp object
                if (TRUE == spStream->Read(pbData, uli.LowPart, &dwRead)
                    && SUCCEEDED(spIInkDisp->Load(vtData)))
                {
                    hr = S_OK;
                }
                ::SafeArrayUnaccessData(vtData.parray);
            }
            ::SafeArrayDestroy(vtData.parray);
        }
    }
}