[Rd] Bug with png() and plot(type="n") (PR#7270)

[Prof Brian Ripley]

On 8 Oct 2004, Peter Dalgaard wrote:

> mcintosh at research.telcordia.com writes:
> 
> > Full_Name: Allen McIntosh
> > Version: 2.0.0
> > OS: Linux
> > Submission from: (NULL) (67.80.175.118)
> > 
> > 
> > Observed the bug with the following combinations: (RedHat 7.3, R 1.6.0) (RedHat
> > 7.3, R 1.9.1) (Redhat 9, R2.0.0).
> > 
> > In the second plot (.png file) produced by the following sequence:
> > 
> > png(file="x%d.png")
> > plot(1:10,1:10,main="ooo",type="n")
> > segments(1:9,1:9,2:10,1:9)
> > plot(1:10,10:1,main="XXXX",type="n")
> > 
> > the axis labels, the tick marks and the title from the first plot have not been
> > erased.  The call to segments() seems to be necessary, as does type="n".  The
> > example I extracted this from also called abline(), which was sufficient to
> > trigger the bug.  Inserting a call to frame() after the call to segments()
> > results in an extra file that ought to be blank, but instead contains the
> > offending text and tick marks.
> > 
> > Workarounds short of multiple calls to png() appreciated.
> 
> Apparently, the clipping of segments is still active when the drawing
> surface is erased.

Yes, and a fix has now been committed to R-patched/R-devel.

-- 
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)
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