Returns S_OK if successful, or an error value otherwise.

Use this method to get the quality factor range that is valid for a LEAD Bitmap Encoder. First call GetSubFormats to get an array of valid sub-formats for the particular LEAD bitmap encoder.  When calling the GetQualityFactorRange method, pass the index of the sub-format array for the uSubFormatIndex argument.

LEAD Bitmap Encoders that have a QualityFactor property bag item use this number to specify the degree of loss in the compression process for lossy formats.  Typical values of the quality factor range are 0 through 255, but this varies depending on the LEAD Bitmap Encoder.  For a list of LEAD Bitmap Encoders that use a quality factor, and a list of the corresponding quality factor ranges, see Quality Factor Property Bag Item.

Reference

LEAD WIC-Enabled Codecs Overview
Registering a LEAD WIC-Enabled Codec
WICLeadEnumName
QualityFactor property bag
WICLeadSubFormatFlags
IWICLeadBitmapEncode::GetQualityFactorPredefined
IWICLeadBitmapEncode::GetQualityFactorPredefinedFriendlyName
WICLeadAbcQualityFactorPredefined
WICLeadCmpQualityFactorPredefined

// ******************************************************************************************************************
// This example lists the quality factor range for one of the LEAD Png Encoder (subformat,guidPixelFormat) pairs
// that support predefined quality factors
// See the Example Requirements for help in running this sample

// MyGetSubFormatFriendlyName gets the friendly name of the subformat
CString MyGetSubFormatFriendlyName(IWICLeadBitmapEncoder *piLeadBitmapEncoder, WICPixelFormatGUID guidPixelFormat, UINT uSubformatIndex)
{
   CString csRet;
   HRESULT hr = S_OK;
   UINT uActual = 0;
   WCHAR *pwzFriendlyName = NULL; 

   if (piLeadBitmapEncoder)
   {
      IWICBitmapEncoder *piBitmapEncoder = NULL;

      // Get subformat friendly name
      IFS(piLeadBitmapEncoder->GetSubFormatFriendlyName(guidPixelFormat, uSubformatIndex, 0, NULL, &uActual));
      if (uActual > 0)
      {
         pwzFriendlyName = new WCHAR[uActual];
         if (pwzFriendlyName)
         {
            IFS(piLeadBitmapEncoder->GetSubFormatFriendlyName(guidPixelFormat, uSubformatIndex, uActual, pwzFriendlyName, &uActual));
            if (SUCCEEDED(hr))
               csRet = pwzFriendlyName;
         }
      }
   }
   DELETE_POINTER(pwzFriendlyName);
   return csRet;
}

HRESULT IWICLeadBitmapEncoder_GetQualityFactorRange(HWND hWnd)
{
   HRESULT hr = S_OK;
   IWICImagingFactory *piImagingFactory = NULL;
   IWICBitmapEncoder *piBitmapEncoder = NULL;
   IWICLeadBitmapEncoder *piLeadBitmapEncoder = NULL;
   CString csExampleName = L"IWICLeadBitmapEncoder_GetQualityFactorPredefined.htm";
   CString csMsg = csExampleName + "\n\n";
   GUID guidContainerFormat = GUID_ContainerFormatLeadPng;
   WICPixelFormatGUID guidPixelFormat = GUID_WICPixelFormat24bppBGR;

   // Create a LEAD TIFF Bitmap Encoder
   IFS(CoCreateInstance(CLSID_WICImagingFactory, NULL, CLSCTX_INPROC_SERVER, IID_IWICImagingFactory, (LPVOID*) &piImagingFactory));
   IFS(piImagingFactory->CreateEncoder(guidContainerFormat, NULL, &piBitmapEncoder));

   // QueryInterface on the encoder to get the IWICLeadBitmapEncoder interface
   IFS(piBitmapEncoder->QueryInterface(IID_WICLeadBitmapEncoder, reinterpret_cast<void**>(&piLeadBitmapEncoder)));

   // **************************************************************************
   // First, get the sub formats for the LEAD Png Encoder with 24 bits per pixel
   // **************************************************************************
   // first call is to get number of subformats
   UINT uSubFormats = 0;
   WICLeadSubFormat *pSubFormats = NULL;
   IFS(piLeadBitmapEncoder->GetSubFormats(guidPixelFormat, 0, NULL, &uSubFormats));
   if (SUCCEEDED(hr))
   {
      pSubFormats = new WICLeadSubFormat[uSubFormats];
      if (pSubFormats)
      {
         // second call is to get the subformats
         IFS(piLeadBitmapEncoder->GetSubFormats(guidPixelFormat, uSubFormats, pSubFormats, &uSubFormats));
      }
   }

   // **************************************************************************
   // Next, get the sub format flags for the sub-formats.  
   // Continue this until we find a subformat that supports WICLeadFlagQualityFactor
   // **************************************************************************
   INT nIndex = -1;
   WICLeadSubFormatFlags uFlags = WICLeadFlagNone;
   for (UINT i=0; i < uSubFormats; i++)
   {
      IFS(piLeadBitmapEncoder->GetSubFormatFlags(guidPixelFormat, i, &uFlags));
      if (uFlags & WICLeadFlagQualityFactor)
         nIndex = i;
   }

   // **************************************************************************
   // If we found a subformat that supports WICLeadFlagQualityFactor,
   // * print the the friendly name for the subformat
   // * print the quality factor range
   // **************************************************************************
    BOOL bQualityFactorRangeSupported = FALSE;
    INT nMinQualityFactor = 0;
    INT nMaxQualityFactor = 0;

   if (nIndex >= 0)
   {
      csMsg = csMsg + L"LEAD Png Encoder sub-format: " + MyGetSubFormatFriendlyName(piLeadBitmapEncoder, guidPixelFormat, nIndex) + L"\n\n";
      IFS(piLeadBitmapEncoder->GetQualityFactorRange(guidPixelFormat, nIndex, &bQualityFactorRangeSupported, &nMinQualityFactor, &nMaxQualityFactor));  
      if (SUCCEEDED(hr) && bQualityFactorRangeSupported)
      {
         CString csTemp;
         csTemp.Format(L"Quality Factor Range:  %d to %d\n", nMinQualityFactor, nMaxQualityFactor);
            csMsg = csMsg + csTemp;
      }
   }
   RELEASE_INTERFACE(piLeadBitmapEncoder);
   RELEASE_INTERFACE(piBitmapEncoder);
   RELEASE_INTERFACE(piImagingFactory);

   MessageBox(hWnd, csMsg, csExampleName, MB_OK);
   return hr;
}