Your driver might also receive the ICM_DRAW_SUGGESTFORMAT message. Typically, this message is sent by the decompression portion of a driver to the drawing portion of a driver to obtain the best decompressed format for the data when the drawing portion can handle several formats. The dwParam1 parameter of ICM_DRAW_SUGGESTFORMAT points to an ICDRAWSUGGEST structure and the dwParam2 parameter specifies its size.
The lpbiIn member specifies a pointer to the structure containing the compressed input format. The lpbiSuggest member specifies a pointer to a buffer used to return the suggested output format.
The dxSrc, dySrc, dxDst, and dyDst members specify the width and height of the source and destination rectangles.
If returning format information, return ICERR_OK. If the lpbiSuggest member is NULL, return the amount of memory required for the suggested output format structure.