[R] Error with strwidth after lattice graphic drawn

[Uwe Ligges]

Prof Brian Ripley wrote:
> On Sat, 20 Nov 2004, Frank E Harrell Jr wrote:
> 
>> In
>>
>> platform i386-pc-linux-gnu
>> arch     i386
>> os       linux-gnu
>> system   i386, linux-gnu
>> status
>> major    2
>> minor    0.1
>> year     2004
>> month    11
>> day      15
>> language R
>>
>> I'm getting an error when using strwidth after a lattice graphic is 
>> drawn:
>>
>> library(lattice)
>> xyplot(runif(20) ~ runif(20))
>> strwidth('xxx')
>>
>> Error in strwidth("xxx") : invalid graphics state
>>
>> Any help appreciated.  I have version 2.0.1 of grid and version 
>> 0.10-14 of lattice.
> 
> 
> The advice is `don't do that'!
> 
> strwidth() is a base graphics command, and will only work if a device is 
> currently plotting base graphics.  Lattice is built on grid, which has
> stringWidth().
> 

... and convertWidth() is useful to display stuff afterwards in an 
interpretable way  ...

Uwe Ligges