[R] Help using gPath
h.wickham at gmail.com
Sun Aug 12 17:13:51 CEST 2007
> Here's a partial extract from a sample session after running your code
> (NOTE this is using the development version of R; grid.ls() does not
> exist in R 2.5.1 or earlier):
> Inspect the grob tree with grid.ls() (similar to Hadley's
> current.grobTree(), but with different formatting) ...
(I'll probably remove current.grobTree as soon as grid.ls makes it to
a released version of R)
> > grid.ls()
> # OUTPUT TRUNCATED
The format is much nicer than mine!
> ... It is not necessarily obvious which grob is which,
> but a little trial and error (e.g., grid.edit() to change
> the colour of a grob) shows that the border on the first
> panel is 'guide.rect.92', which is a child of 'plot.gTree.113'
> (NOTE the numbers come from a fresh R session).
I will try and rename these grobs so that they are more easily
accessible (and reproducible across multiple calls). That should make
things easier in the future.
> Use grid.get() to grab that gTree and inspect that
> further using grid.ls(), this time also showing the
> viewports involved ...
What do all the upViewports represent? Could the downViewports be
incorporating into the same place as the original definition?
> (The remaining code should work for you in your version of R; it
> is just grid.ls() that is new.)
> Remove the original border rect, ...
> > grid.remove("guide.rect.92", global=TRUE)
> ... (need global=TRUE because the border appears twice as a child
> of 'plot.gTree.113' [not sure why that is]) then add some lines that
> only draw the top, right, and bottom borders ...
> > grid.add("plot.gTree.113",
> linesGrob(c(0, 1, 1, 0), c(1, 1, 0, 0),
> vp=vpPath("layout", "panel_1_1")))
> ... (I drew the new lines green so that they are easy to see).
> NOTE that in order to put the new lines in the same "place" as
> the original border, the new lines are added as children of the
> gTree 'plot.gTree.113' and they have a vpPath to make sure
> they get drawn in the right viewport within that gTree.
Do you think it would be worth drawing all these rectangles as lines
to make them easier to edit?
> What would probably be ideal would be a graphical interface to the
> grid.ls()-type information (something like an object explorer) that
> would make it easier to see which object is which and also make it
> easier to add and remove objects. A nice student project perhaps :)
That would be great!
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