I googled a bit and found that cairo needs to be installed on Ubuntu.
Through Ubuntu package manager, I installed package r-cran-cairodevice, but
that doesn't seem to solve the problem.

Aditya

On Thu, Jan 27, 2011 at 10:43 AM, Aditya Bhagwat <bhagwataditya@gmail.com>wrote:

> Dear Prof. Ripley,
>
> Thanks for your reply.
>
> This is one of the main points of supporting semi-transparent colours.
>> You haven't told us your platform or graphics device (see the posting
>> guide), but plotting with something like col=rgb(0,0,0,0.2) may work.
>
>
> I am working on Ubuntu Linux. and I tried the suggested approach but got an
> empty plot and the following warning message:
> In plot.xy(xy, type, ...) :
>   semi-transparency is not supported on this device: reported only once per
> page
>
> Any suggestions on how to proceed?
>
> Many thanks,
>
> Aditya
>
>
>
>>
>> On Thu, 27 Jan 2011, Aditya Bhagwat wrote:
>>
>>  Dear all,
>>>
>>> When making a plot with the command plot(xVector, yVector), there are
>>> many
>>> points that collide on the same place in the plot. In order to make this
>>> plot clearer, I have been looking for a way to colour the points based on
>>> the number of points that fall onto each other. If only one point falls
>>> on a
>>> particular location, make it gray, if many points fall, make it black.
>>>
>>> I tried to search the help archives, but didn't find any useful answers.
>>> Anyone has any suggestion?
>>>
>>> Many thanks for your help!
>>>
>>> Aditya
>>>
>>> --
>>> Aditya Bhagwat
>>>
>>>        [[alternative HTML version deleted]]
>>>
>>> ______________________________________________
>>> R-help@r-project.org mailing list
>>> https://stat.ethz.ch/mailman/listinfo/r-help
>>> PLEASE do read the posting guide
>>> http://www.R-project.org/posting-guide.html
>>> and provide commented, minimal, self-contained, reproducible code.
>>>
>>>
>> --
>> Brian D. Ripley,                  ripley@stats.ox.ac.uk
>> Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/<http://www.stats.ox.ac.uk/%7Eripley/>
>> University of Oxford,             Tel:  +44 1865 272861 (self)
>> 1 South Parks Road,                     +44 1865 272866 (PA)
>> Oxford OX1 3TG, UK                Fax:  +44 1865 272595
>>
>
>
>
> --
> Aditya Bhagwat
>
>
>


-- 
Aditya Bhagwat

	[[alternative HTML version deleted]]

