IWICBitmapLock::GetDataPointer method (wincodec.h)

Article
02/22/2024

Gets the pointer to the top left pixel in the locked rectangle.

Syntax

HRESULT GetDataPointer(
  [out] UINT             *pcbBufferSize,
  [out] WICInProcPointer *ppbData
);

Parameters

[out] pcbBufferSize

Type: UINT*

A pointer that receives the size of the buffer.

[out] ppbData

Type: BYTE**

A pointer that receives a pointer to the top left pixel in the locked rectangle.

Return value

Type: HRESULT

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

Remarks

The pointer provided by this method should not be used outside of the lifetime of the lock itself.

GetDataPointer is not available in multi-threaded apartment applications.

Examples

In the following example, the data pointed to by the IWICBitmapLock is zeroed.


    IWICImagingFactory *pFactory = NULL;
    IWICBitmap *pBitmap = NULL;

    UINT uiWidth = 640;
    UINT uiHeight = 480;
    WICPixelFormatGUID formatGUID = GUID_WICPixelFormat32bppARGB;

    WICRect rcLock = { 0, 0, uiWidth, uiHeight };
    IWICBitmapLock *pLock = NULL;

    HRESULT hr = CoCreateInstance(
        CLSID_WICImagingFactory,
        NULL,
        CLSCTX_INPROC_SERVER,
        IID_IWICImagingFactory,
        (LPVOID*)&pFactory
        );

    if (SUCCEEDED(hr))
    {
        hr = pFactory->CreateBitmap(uiWidth, uiHeight, formatGUID, WICBitmapCacheOnDemand, &pBitmap);
    }

    if (SUCCEEDED(hr))
    {
        hr = pBitmap->Lock(&rcLock, WICBitmapLockWrite, &pLock);

        if (SUCCEEDED(hr))
        {
            UINT cbBufferSize = 0;
            UINT cbStride = 0;
            BYTE *pv = NULL;

            // Retrieve the stride.
            hr = pLock->GetStride(&cbStride);

            if (SUCCEEDED(hr))
            {
                hr = pLock->GetDataPointer(&cbBufferSize, &pv);
            }
            if (SUCCEEDED(hr))
            {
                // Access the bitmap memory starting at pv, where
                // each row begins cbStride bytes after the start
                // of the preceding row.
            }

            // Release the bitmap lock.
            pLock->Release();
        }
    }

    if (pBitmap)
    {
        pBitmap->Release();
    }

    if (pFactory)
    {
        pFactory->Release();
    }

    return hr;

Requirements

Requirement	Value
Minimum supported client	Windows XP with SP2, Windows Vista [desktop apps \| UWP apps]
Minimum supported server	Windows Server 2008 [desktop apps \| UWP apps]
Target Platform	Windows
Header	wincodec.h
Library	Windowscodecs.lib
DLL	Windowscodecs.dll

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