[R] background color for plotting symbols in 'matplot'

[joerg van den hoff]

something like


matplot2(matrix(1:6,3,2),matrix(7:12,3,2),pch=21,bg=c(2,3),type='b')


does not yield the expected (at least by me) result: only the points on 
the first line get (successively) background colors for the plotting 
symbols, the second line gets no background color at all for its 
plotting symbols.

I think the natural behaviour should be two curves which (for the 
example given above) symbol-background colors 2 and 3, respectively (as 
would be obtained by a suitable manual combination of 'plot' and 
'lines'). the modification of the matplot code to achieve this 
behaviour is obvious as far as I can see (adding 'bg' to the explicit 
arguments of matplot and handling similar to 'lty', 'cex' and the like 
inside the function including transfer to 'plot' and 'lines' argument list).


is the present behaviour a bug of 'matplot' or is it for some reason 
intended behaviour?


regards,

joerg