[R] plot symbol "+", but with variable bar lenghts

[baptiste Auguié]

Hi,


The TeachingDemos package has a my.symbols() function that you could use with you own glyph.

HTH,

baptiste


On Sep 9, 2010, at 9:36 AM, (Ted Harding) wrote:

> On 09-Sep-10 06:41:34, Rainer Machne wrote:
>> Hi,
>> does anybody know of some plotting function or an easy way to 
>> generate "+" symbols with individually settable bar lengths?
>> I tried just combining "|" and "-" as pch and setting the size via cex,
>> but that doesn't really work since the two symbols have different
>> default lengths. Is there a horizontal | or a longer "-" available?
>> 
>> Thanks,
>> Rainer
> 
> I tried this using pch="_" for the horizontal bar, but it is only
> about half the length of the pch="|" bar. However, compared with the
> same plot using pch="+", at least the resulting cross went through
> the centre of the "+" cross. To increase the length of the "_" to
> equal that of the "|" would require some empirical fiddling with
> 'cex=..." and would increase the thickness of the "_".
> 
> I don't know of any way to create a symbol using drawing commands,
> and assigning the result to a "character" which could be evoked
> using 'pch="..."', which would seem to be the sort of thing you
> would like to be able to do. This could be a useful extension to
> the plot() function and friends.
> 
> You can of course define an auxiliary function, say mycross(),
> on the lines of
> 
>  mycross <- function(x,y,L,U,R,D){
>    lines(c(x,x-L),c(y,y))
>    lines(c(x,x),c(y,y+U))
>    lines(c(x,x+R),c(y,y))
>    lines(c(x,x),c(y,y-D))
>  }
> 
> but then you would have to explicitly apply this to the data,
> rather than delegate it to the plot() function's pch option.
> 
> Ted.
> 
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> E-Mail: (Ted Harding) <Ted.Harding at manchester.ac.uk>
> Fax-to-email: +44 (0)870 094 0861
> Date: 09-Sep-10                                       Time: 08:36:36
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