IsAlphaPremultRequired method

Called by the filter to determine whether to remove the opacity of a layer by premultiplying it against the palette colors.

Syntax

HRESULT retVal = object.IsAlphaPremultRequired(pfPremultAlpha);

Parameters

• pfPremultAlpha [out]
  Type: BOOL

  Address of a BOOL variable that receives TRUE if a premultiply operation is required, or FALSE otherwise.

Return value

Type: HRESULT

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

Remarks

A premultiply operation, where color components are adjusted by their corresponding alpha components, is required if the image palette contains alpha information and the palette is being converted to BFID_RGBA_32 format.