NO_CORNER
if ((fCurrentCorner == fNeverBlankCorner && fNeverBlankCorner != NO_CORNER)
if (fBlankCorner != NO_CORNER || fNeverBlankCorner != NO_CORNER) {
if (fCurrentCorner == fBlankCorner && fBlankCorner != NO_CORNER
fCurrentCorner = NO_CORNER;
fCurrentCorner(NO_CORNER),
fBlankCorner = NO_CORNER;
fNeverBlankCorner = NO_CORNER;
if (fCurrentCorner != NO_CORNER)
case NO_CORNER:
corner = NO_CORNER;
return NO_CORNER;
fCurrentCorner(NO_CORNER),