Message-ID: <Pine.LNX.4.61.0510051556450.32141@gannet.stats>
Date: 2005-10-05T15:10:58Z
From: Brian Ripley
Subject: transparent surface in rgl
In-Reply-To: <4343DBB8.6050701@stats.uwo.ca>
On Wed, 5 Oct 2005, Duncan Murdoch wrote:
> On 10/5/2005 9:31 AM, Prof. Paul R. Fisher wrote:
>> Hi all
>> I am a complete newbie to this list (just subscribed) and a newcomer to
>> R (an S user from olden times). I have been using scatter3d to create a
>> 3d scatter plot with surface. The graphic is created within the rgl
>> package and I have used rgl.postscript to export it so I can generate a
>> publication quality image. My problem is that the plotted surface is no
>> longer transparent in the postscript output ie. the rgl.spheres that are
>> behind the surface disappear in the postscript image. Can't seem to find
>> any info on this anywhere. Am I doing something wrong? Is there an easy fix?
>
> I think Postscript doesn't support transparency (or at least the version
> of Postscript that the rgl.postcript function targets doesn't support
> it). You may have to export a bitmapped format using the rgl.snapshot()
> function. If your original window is very large this may give you good
> enough quality.
Common PostScript (level 2) does not support either full or partial
transparency (and I guess partial transparency is meant here or the
surface could just not be plotted). It would be good to have a rgl.pdf
which did. These days PDF is the `portable PostScript' and since version
1.4 has had alpha-channel supoort.
Ref:
http://en.wikipedia.org/wiki/Transparent_pixels#Transparency_in_PostScript
--
Brian D. Ripley, ripley at stats.ox.ac.uk
Professor of Applied Statistics, http://www.stats.ox.ac.uk/~ripley/
University of Oxford, Tel: +44 1865 272861 (self)
1 South Parks Road, +44 1865 272866 (PA)
Oxford OX1 3TG, UK Fax: +44 1865 272595