IWICColorTransform::Initialize method (wincodec.h)

Article
10/13/2021

Initializes an IWICColorTransform with a IWICBitmapSource and transforms it from one IWICColorContext to another.

Syntax

HRESULT Initialize(
  [in] IWICBitmapSource      *pIBitmapSource,
  [in] IWICColorContext      *pIContextSource,
  [in] IWICColorContext      *pIContextDest,
  [in] REFWICPixelFormatGUID pixelFmtDest
);

Parameters

[in] pIBitmapSource

Type: IWICBitmapSource*

The bitmap source used to initialize the color transform.

[in] pIContextSource

Type: IWICColorContext*

The color context source.

[in] pIContextDest

Type: IWICColorContext*

The color context destination.

[in] pixelFmtDest

Type: REFWICPixelFormatGUID

The GUID of the desired pixel format.

This parameter is limited to a subset of the native WIC pixel formats, see Remarks for a list.

Return value

Type: HRESULT

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

Remarks

The currently supported formats for the pIContextSource and pixelFmtDest parameters are:

GUID_WICPixelFormat8bppGray
GUID_WICPixelFormat16bppGray
GUID_WICPixelFormat16bppBGR555
GUID_WICPixelFormat16bppBGR565
GUID_WICPixelFormat24bppBGR
GUID_WICPixelFormat24bppRGB
GUID_WICPixelFormat32bppBGR
GUID_WICPixelFormat32bppBGRA
GUID_WICPixelFormat32bppPBGRA
GUID_WICPixelFormat32bppPRGBA (Windows 8 and later)
GUID_WICPixelFormat32bppRGBA
GUID_WICPixelFormat32bppBGR101010
GUID_WICPixelFormat32bppCMYK
GUID_WICPixelFormat48bppBGR
GUID_WICPixelFormat64bppBGRA (Windows 8 and later)
GUID_WICPixelFormat64bppPBGRA (Windows 8 and later)
GUID_WICPixelFormat64bppPRGBA (Windows 8 and later)
GUID_WICPixelFormat64bppRGBA (Windows 8 and later)

In order to get correct behavior from a color transform, the input and output pixel formats must be compatible with the source and destination color profiles. For example, an sRGB destination color profile will produce incorrect results when used with a CMYK destination pixel format.

Examples

The following example performs a color transform from one IWICColorContext to another.


    IWICImagingFactory *pFactory = NULL;
    IWICBitmapDecoder *pDecoder = NULL;
    IWICBitmapFrameDecode *pBitmapFrame = NULL;
    IWICColorContext *pContextSrc = NULL;
    IWICColorContext *pContextDst = NULL;
    IWICColorTransform *pColorTransform = NULL;

    UINT uiFrameCount = 0;

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

    if (SUCCEEDED(hr))
    {
        hr = pFactory->CreateDecoderFromFilename(
                           L"test.jpg",
                           NULL,
                           GENERIC_READ,
                           WICDecodeMetadataCacheOnDemand,
                           &pDecoder);
    }

    if (SUCCEEDED(hr))
    {
        hr = pDecoder->GetFrameCount(&uiFrameCount);
    }

    if (SUCCEEDED(hr) && (uiFrameCount > 0))
    {
        hr = pDecoder->GetFrame(0, &piBitmapFrame);
    }

    if (SUCCEEDED(hr))
    {
        hr = pFactory->CreateColorContext(&pContextSrc);
    }

    if (SUCCEEDED(hr))
    {
        hr = pContextSrc->InitializeFromFilename(
                              L"c:\\windows\\system32\\spool\\drivers\\color\\kodak_dc.icm");
    }

    if (SUCCEEDED(hr))
    {
        hr = pFactory->CreateColorContext(&pContextDst);
    }

    if (SUCCEEDED(hr))
    {
        hr = pContextDst->InitializeFromFilename(
                              L"c:\\windows\\system32\\spool\\drivers\\color\\sRGB Color Space Profile.icm");
    }

    hr = E_FAIL;

    if (SUCCEEDED(hr))
    {
        // Transform from src icm to the destination icm. 
        hr = pColorTransform->Initialize( pBitmapFrame,
                                          pContextSrc,
                                          pContextDst,
                                          GUID_WICPixelFormat32bppBGRA);
    }

    if (SUCCEEDED(hr))
    {
        UINT uiWidth = 0, uiHeight = 0;
        UINT cbStride = 0;
        UINT cbBufferSize = 0;
        BYTE *pbBuffer = NULL; 

        hr = pColorTransform->GetSize(&uiWidth, &uiHeight);

        if (SUCCEEDED(hr))
        {
            WICRect rc = { 0 };
            rc.X = 0;
            rc.Y = 0;
            rc.Width = uiWidth;
            rc.Height = 1; // scanline

            for (UINT i = 0; SUCCEEDED(hr) && (i < uiHeight); i++)
            {
                hr = pColorTransform->CopyPixels(&rc, cbStride, cbBufferSize - (rc.Y * cbStride), pbBuffer);
                pbBuffer += cbStride;
                rc.Y += 1;
            }
        }
    }

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

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

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

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

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

    if (pColorTransform)
    {
        pColorTransform->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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