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

[Stephen.Harker at spme.monash.edu.au]

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)

X11() 

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)