NullMatrix       1848 magick/feature.c   if (NullMatrix(accumulator) == MagickFalse)
NullMatrix         38 magick/matrix.h   NullMatrix(MatrixInfo *),
NullMatrix        373 magick/shear.c   if (NullMatrix(source_matrix) == MagickFalse)
NullMatrix        444 magick/shear.c   (void) NullMatrix(source_matrix);