The ICM_DRAW_SUGGESTFORMAT message is sent to a rendering driver to have it suggest a decompressed format that it can draw.
Parameters
dwParam1
Specifies a pointer to an ICDRAWSUGGEST data structure.
dwParam2
Specifies the size of the ICDRAWSUGGEST data structure.
Return Value
Returns ICERR_OK if successful. If lpbiSuggest is NULL, returns the amount of memory to hold the format that would have been suggested.
Comments
The driver should examine the format specified in the lpbiIn member of the ICDRAWSUGGEST structure and use the lpbiSuggest member to return a format it can draw. The returned format should be as similar as possible to the input format.
For example, if the driver can draw only 8 or 16-bit RGB data, and the input format is 320-by-240-by-16-bit MSVideo1 compressed data, the renderer suggests the 320-by-240-by-16-bit RGB format.
Optionally, the driver can use the installable compressor handle passed in hicDecompressor to make more complex selections. For example, if the input format is 24-bit JPEG data, a renderer could query the compressor to find out if it can decompress to a YUV format (which might be drawn more efficiently) before selecting the format to suggest.