Hi
I have committed this fix to r-devel (r76226).
Please let me know if this does not fix things for you.
Paul
On 5/03/19 8:22 PM, Lee Steven Kelvin wrote:
Hi Paul,
Great, thank you for looking in to this, and I'm glad that you're able
to reproduce it at your end too.
From your reply, I'm happy that it seems like the fix may be fairly
trivial, but I understand the necessity for caution.
If there's anything else I can do to help, please do let me know.
Thank you again,
Best,
Lee
On Monday, 4 March 2019, Paul Murrell <p...@stat.auckland.ac.nz
<mailto:p...@stat.auckland.ac.nz>> wrote:
Hi
(cc'ed to r-devel where further discussion should probably take place)
Thanks Lee. I see that problem.
There is a "+ 1" in the Cairo device code for setting the clipping
region
(https://github.com/wch/r-source/blob/ba600867f2a94e46cf9eb75dc8b37f12b08a4561/src/library/grDevices/src/cairo/cairoFns.c#L156
<https://github.com/wch/r-source/blob/ba600867f2a94e46cf9eb75dc8b37f12b08a4561/src/library/grDevices/src/cairo/cairoFns.c#L156>)
Remove the "+ 1" and the problem goes away (for your example at least).
The comment on the line above that code suggests that the "+ 1" was
modelled on the X11 device code, but X11 deals in integer pixels and
Cairo (at the API level) does not, so it would seem that the "+ 1"
is just unnecessary.
However, I have a slight nagging worry that we have been here
before, so I would like to do some more testing before committing
that change.
Paul
On 1/03/19 8:13 AM, Lee Steven Kelvin wrote:
Hello all,
When producing a plot in R using the cairo_pdf device, the
resultant plot does not respect the plotting boundaries. Lines
and shaded regions will spill over the lower x-axis and the
right-side y-axis (sides 1 and 4). I would like to know if it is
possible to fix this behaviour when using 'cairo_pdf' in R?
As an example, see the image at this web link:
https://i.stack.imgur.com/0lfZd.png
<https://i.stack.imgur.com/0lfZd.png>
This image is a screenshot of a PDF file constructed using the
following minimum working example code:
cairo_pdf(file="test.pdf", width=0.5, height=0.5)
par("mar"=c(0.25,0.25,0.25,0.25))
plot(NA, xlim=c(0,1), ylim=c(0,1), axes=FALSE)
polygon(x=c(-1,-1,2,2), y=c(-1,2,2,-1), density=5, col="green3",
lwd=10)
abline(h=0.25, col="red", lwd=5)
abline(h=0.75, col="hotpink", lwd=5, lend=1)
abline(v=0.25, col="blue", lwd=5)
abline(v=0.75, col="cyan", lwd=5, lend=1)
box()
dev.off()
Here I'm plotting a shaded region in green using 'polygon', with
boundaries that lie outside the plot. I'm also drawing two sets
of horizontal/vertical lines using 'abline'. The first in each
pair uses standard rounded line caps, whilst the second in each
pair uses butt line caps.
As you can see, the shading lines and the default rounded-end
ablines all extend beyond the plotting region along the lower
and right-hand side axes. Only when using 'lend=1' am I able to
contain the ablines to the plotting region. I know of no such
fix for the shading lines however.
I would naively expect the R plotting region to be respected,
and for it to be impossible to plot outside of this region
unless explicitly specified by the user.
I have tested this on the other cairo devices (SVG and PS), and
also reproduce the same behaviour, indicating that this is an
issue with the cairo graphics API, or its implementation within R.
This behaviour does not occur when using the standard R 'pdf'
graphics device. I would switch to 'pdf' in general, however,
'cairo_pdf' has several advantages over 'pdf', notably, reduced
output file sizes on occasion and support for a larger array of
UTF-8 characters, so ideally I would prefer to use cairo_pdf.
I should note that I have also posted this message on
StackOverflow at this web link:
https://stackoverflow.com/questions/54892809/r-cairo-pdf-function-does-not-respect-plotting-boundaries
<https://stackoverflow.com/questions/54892809/r-cairo-pdf-function-does-not-respect-plotting-boundaries>
Thank you in advance for any insights into this issue.
Sincerely,
Lee Kelvin
--
Dr Lee Kelvin
Department of Physics
UC Davis
One Shields Avenue
Davis, CA 95616
USA
Ph: +1 (530) 752-1500
Fax: +1 (530) 752-4717
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--
Dr Lee Kelvin
Department of Physics
UC Davis
One Shields Avenue
Davis, CA 95616
USA
Ph: +1 (530) 752-1500
Fax: +1 (530) 752-4717
--
Dr Paul Murrell
Department of Statistics
The University of Auckland
Private Bag 92019
Auckland
New Zealand
64 9 3737599 x85392
p...@stat.auckland.ac.nz
http://www.stat.auckland.ac.nz/~paul/
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