[Rd] R postscript generation error (lines versus points) (PR#5285)

[Paul Murrell]

Hi


Peter Dalgaard wrote:
 > Stephen.Harker at spme.monash.edu.au writes:
 >
 >
 >>Full_Name: Stephen Harker
 >>Version: 1.80
 >>OS: linux (Yellow Dog 3.0 on ppc)
 >>Submission from: (NULL) (130.194.13.101)
 >>
 >>
 >>In creating a postscript file from a set of data in which the points are
 >>plotted
 >>using `points()' and lines drawn using `lines()' I have found since 
upgrading
 >>from R version 1.4? to 1.8 that the two sets do not coinicide 
completely.  This
 >>is best illustrated by a simple example given below.  Here the X11() 
output
 >>appears correctly.  However, the postscript output shows that the 
lines and
 >>points no
 >>longer coincide on the right hand side, whereas the left hand side is 
perfect.
 >>Output to other devices such as pdf is perfect.  Possibly this reflects a
 >>different scaling being applied when points() or lines() are selected.
 >>
 >>One reason I found this is that I use a number of scripts in R to 
plot and
 >>multiplot data sets from x-ray and neutron powder diffraction 
analysis (and
 >>Rietveld fitting of this data in particularl).  In these points() is 
used to
 >>plot the data and lines() to plot the refinement from the analysis. 
After
 >>upgrading I found these were
 >>misaligned.  The example was created to mimic the problem.
 >>
 >>%%% Example follows:
 >>dtwoth <- seq(from=20,to=80,len=1024)
 >>dcount <- rnorm(dtwoth) #
 >>
 >>postscript(file="R-test2.ps",horizontal=FALSE,
 >>         pointsize=18, onefile=FALSE,
 >>         family="Helvetica", paper="a4")
 >>
 >>plot(dtwoth,dcount,
 >>  xlim=c(min(dtwoth),max(dtwoth)),ylim=c(min(dcount),max(dcount)),
 >> yaxt="n",xaxs="i",yaxs="i",xlab="2theta",ylab="counts",
 >> type="n")
 >>
 >>lines(dtwoth,dcount)
 >>points(dtwoth,dcount)
 >
 >
 > [At the current rate, "1.80" would be about 36 years into the future.
 > Latest version is 1.8.1.]
 >
 > I can't reproduce this with 1.8.0 on RedHat 8.0. Are you sure it isn't
 > your Postscript viewer that is playing tricks on you??


I can't reproduce this either, but in trying your script I wonder if you 
are not properly "finishing" the postscript plot by calling dev.off 
before viewing.  If I run your script, then view R-test2.ps without 
quitting R, the last few points at the right end of the plot are missing 
(because the postscript file is not yet complete).  If I then quit R 
(the postscript file is completed and closed), the postscript output 
looks just like the X11 version.

Paul
-- 
Dr Paul Murrell
Department of Statistics
The University of Auckland
Private Bag 92019
Auckland
New Zealand
64 9 3737599 x85392
paul at stat.auckland.ac.nz
http://www.stat.auckland.ac.nz/~paul/