kPlaneRGB1
fHalftone->SetPlanes(Halftone::kPlaneRGB1);
halftone->SetPlanes(Halftone::kPlaneRGB1);
ASSERT(planes == kPlaneRGB1);
if (fPlanes == kPlaneRGB1) {
halftone.SetPlanes(Halftone::kPlaneRGB1);