[R-SIG-Mac] dash spacing and slope in quartz device

[Kenneth Knoblauch]

Hi,

There was some discussion about slowdowns in the new quartz
device a few weeks ago that had to do with line drawing but
I don't think that the following has been mentioned.

I've noticed a "new" behavior in the quartz device that can be seen
by running

xx <- seq(1:100)
plot(xx, xx^2, type = "l", lty = 2)

On my display, the dash spacing disappears for xx < 40
for the default window size.
In addition, the dashes are obliterated by increasing the
line width,

lines(xx, 0.5 * xx^2, lty = 2, lwd = 2)

unless I enlarge the window.  The same occurs for lty = 3.

The dash spacing seems to depend on the slope of the contour.

plot(rep(1, 100), lty = 2, type = "l", ylim = c(0, 100))
lines(xx, lty = 2)
lines(2 * xx, lty = 2)

This did not occur in an earlier version of R that I tried (R 2.2.0)
and does not occur in other graphic devices that I have tried
(x11 and pdf, so far).

sessionInfo()
R version 2.7.0 Patched (2008-05-28 r45808)
i386-apple-darwin8.10.1

locale:
en_US.UTF-8/en_US.UTF-8/C/C/en_US.UTF-8/en_US.UTF-8

attached base packages:
[1] stats     graphics  grDevices utils     datasets  methods   base

Does anyone else see this?  Apologies in advance if this is normal
behavior.  Thank you.

best,

Ken


-- 
Ken Knoblauch
Inserm U846
Institut Cellule Souche et Cerveau
Département Neurosciences Intégratives
18 avenue du Doyen Lépine
69500 Bron
France
tel: +33 (0)4 72 91 34 77
fax: +33 (0)4 72 91 34 61
portable: +33 (0)6 84 10 64 10
http://www.sbri.fr