[R] rgl.Sweave not producing transparency in pdf plots with alpha

[Duncan Murdoch]

On 02/05/2012 12:26 PM, Duncan Murdoch wrote:
> On 02/05/2012 11:00 AM, Alexander Shenkin wrote:
> >  Hi Folks,
> >
> >  I'm trying to get rgl.Sweave to produce plots with transparency.
> >  However, it just seems to produce opaque plots when pdf is the output
> >  type.  Perhaps this is a known issue?  I'll just use .png in the
> >  meantime, but wanted to see about this, as I didn't see it in the
> >  documentation (though it's possible I missed it).
> That uses the rgl.postscript() function, which uses the GL2PS library to
> convert to PDF.  It may be that it doesn't support transparency in your
> scene.  Or perhaps it just hasn't been turned on:  GL2PS didn't support
> transparency when rgl.postscript was written.

I just took a look:  transparency is turned off, and when it's turned 
on, it doesn't look very good.

It's possible that there are tuning parameters that could make it look 
good, but I don't know what they are.

Duncan Murdoch

>
> Duncan Murdoch
>
> >
> >  Thanks,
> >  Allie
> >
> >
> >
> >
> >  \documentclass{article}
> >  \title {rgl test}
> >  \usepackage{Sweave}
> >  \begin {document}
> >
> >  This is a test of rgl.sweave's alpha capability.
> >
> >  \begin{figure}
> >  % uncomment line below for png output (correct transparency)
> >  %<<echo=FALSE, grdevice=rgl.Sweave, fig=TRUE, width=5, height=5,
> >  resolution=100>>=
> >  <<echo=FALSE, grdevice=rgl.Sweave, fig=TRUE, width=5, height=5,
> >  resolution=100, outputtype=pdf, pdf=TRUE>>=
> >  library(rgl)
> >  data(volcano)
> >  z<- 2 * volcano        # Exaggerate the relief
> >  x<- 10 * (1:nrow(z))   # 10 meter spacing (S to N)
> >  y<- 10 * (1:ncol(z))   # 10 meter spacing (E to W)
> >  zlim<- range(y)
> >  zlen<- zlim[2] - zlim[1] + 1
> >  colorlut<- terrain.colors(zlen) # height color lookup table
> >  col<- colorlut[ z-zlim[1]+1 ] # assign colors to heights for each point
> >  #open3d()
> >  surface3d(x, y, z, color=col, back="lines", alpha=0.75)
> >  @
> >  \end{figure}
> >
> >  \end{document}
> >
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> >  and provide commented, minimal, self-contained, reproducible code.
>