problem clipping R postscript plots within latex (PR#623)

Martin Maechler <maechler@stat.math.ethz.ch> writes:

(from R-help)
    PD> Stephen Eglen <stephen@cogsci.ed.ac.uk> writes:

    >  > > generated by R into a latex document.  Specifically, the latex package
    >  > > graphicsx allow you to specify the bounding box of the postscript
    >  > > file, so that you can just show _part_ of the postscript file if you
    >  > > tell it to also clip the area outside of the bounding box.

    > ...

    >  > Ow. This stems from the use of "initclip" in the R-generated PS. One
    >  > shouldn't do that, one should bracket clipped graphics within
    >  > gsave/grestore instead. Sounds a bit tricky to get right.

    > 
    > Thanks.  To solve my current problem, I changed the definition of the
    > `cl' operator in the postscript file to:
    > 
    > /cl  { gsave initclip newpath 3 index 3 index moveto 1 index
    >        4 -1 roll lineto  exch 1 index lineto lineto
    >        closepath clip grestore newpath } def
    > 
    > [i.e. just adding the gsave ... grestore pair]
    > 
    > Whether this is the proper solution though is another matter...

    PD> It isn't. It grestore-s before actually plotting the stuff that
    PD> needs to be clipped, so effectively you just disabled R's
    PD> clipping. A better way would be to start the plotting with a "gs"
    PD> and have

    /cl  { gr gs newpath 3 index 3 index moveto 1 index
	   4 -1 roll lineto  exch 1 index lineto lineto
	   closepath clip newpath } def

    PD> and end everything with a "gr". Not too sure that is perfectly
    PD> safe, though...

Are you working on this, Peter?
Otherwise, "R-bugs" should probably get about the above report..

Done...