png_permit_mng_features -- enable MNG extensions for PNG image wrapped in MNG datastream


#include <png.h>

png_uint_32 png_permit_mng_features(png_structp png_ptr, png_uint_32 mng_features_permitted);


This interface shall enable some MNG extensions for a PNG image wrapped in a MNG datastream.

The parameter png_ptr shall specify the PNG image.

The parameter mng_features_permitted shall specify the logical OR of the features to be enabled, possibly including PNG_ALL_MNG_FEATURES, PNG_FLAG_MNG_EMPTY_PLTE, and PNG_FLAG_MNG_FILTER_64.

Return Value

This interface shall return the logical AND of the parameter mng_features_permitted with the set of MNG features supported by the local version of libpng.

Application Usage (informational)

This interface may not read or write a standalone PNG file; the PNG datastream must be embedded in a MNG datastream with an 8-byte MNG signature and MEND and MHDR chunks.