pub fn graphic(n: &[u8]) -> Option<Graphic>Expand description
The picture of the GROB n (all its nibbles, prolog first), or None
when it is not a GROB, has no pixels (0 wide or high, as #0 #0 BLANK makes), is too large, or its fields do not add up. The
layout (wiki: protocols/hp-object-format, “GROB layout”): prolog
#02B1E, length, height, width (5 nibbles each, low nibble first), then
the rows, each padded to a whole number of bytes; within a nibble the
least significant bit is the leftmost pixel.