I've had a chance to read the source more thoroughly. The chain of
events is as follows:
1. Local function `plotts()` is defined with argument `cex` that
defaults to `par("cex")`
2. `...` is passed to `plotts()`. If "cex" is an element in `...`,
inside `plotts()` the variable `cex` is assigned thereby (overriding the
default arg). Importantly, this means that the element "cex" is captured
and _removed_ from `...`. `...` is eventually passed to `plot.window()`.
3.
- In the univariate case (NCOL(x) == 1): When `lines.default()` is
called to actually plot the data
(https://github.com/wch/r-source/blob/trunk/src/library/stats/R/ts.R#L588
and
https://github.com/wch/r-source/blob/trunk/src/library/stats/R/ts.R#L597
for reference), `cex` is not included in the call.
- In the bivariate case (NCOL(x) > 1): Because "cex" was captured and
removed from `...`, it is not passed to `plot.default` when it is called
(https://github.com/wch/r-source/blob/trunk/src/library/stats/R/ts.R#L548).
It turns out that the "eating" is not being done by `...` but by the
signature of `plotts`.
The documentation currently reads:
...: additional graphical arguments, see 'plot', 'plot.default' and
'par'.
This, to me, suggests parity with the 'plot' function in how the
arguments in '...' are handled. Therefore either the code is wrong or
the documentation is incomplete and misleading.
I filed this is as a bug because it's undocumented, and inconsistent
with how other arguments typically passed through `plot.default` are
handled.
I'll be happy to do the patch myself -- I just need to know which thing
to patch (the source or the docs).
Greg
On 2016-08-25 03:00, David Winsemius wrote:
On Aug 24, 2016, at 5:59 PM, Gregory Werbin
wrote:
I did a search on Bugzilla for "plot.ts" and didn't find anything on
this issue. I tried to sign up for Bugzilla to report it, but my
e-mail address didn't pass your "syntax checking" for a legal e-mail
address.
The bug is easily reproducible on my machine as follows:
## start
# generate some data
y <- arima.sim(list(), 150)
# this will definitely dispatch to a ".ts" method
class(y)[1] == 'ts'
# compare and note that `cex = 0.5` has no effect
plot(y, type = 'b', pch = 16)
plot(y, type = 'b', pch = 16, cex = 0.5)
# it works if `y` is coerced back to a regular vector
plot(as.numeric(y), type = 'b', pch = 16, cex = 0.5)
# another way to see the issue
plot.ts(y, type = 'b', pch = 16, cex = 0.5)
plot.default(y, type = 'b', pch = 16, cex = 0.5)
## end
Skimming through source code for `plot.ts`, it seems like the `cex`
argument is being "eaten" by a `...` somewhere without being properly
passed to `plot.default`.
'...' does not "eat" parameters, it passes them on.
Looking at the very top of the body we see this in the definition of
the internal `plotts` function:
cex = par("cex"), lty = par("lty"), lwd = par("lwd"),
axes = TRUE, frame.plot = axes, ann = par("ann"), cex.lab =
par("cex.lab"),
col.lab = par("col.lab"), font.lab = par("font.lab"),
cex.axis = par("cex.axis"), col.axis = par("col.axis"),
And at the end of the body we se the call to plotts (including the
"dots")
So I would suggest using par-settings.
par(cex=0.5)
plot(y, type = 'b', pch = 16)
(Question seems more appropriate for r-help.)
--
David.
The output of `R.version` is:
platform x86_64-apple-darwin15.5.0
arch x86_64
os darwin15.5.0
system x86_64, darwin15.5.0
status
major 3
minor 3.1
year 2016
month 06
day21
svn rev70800
language R
version.string R version 3.3.1 (2016-06-21)
nickname Bug in Your Hair
Greg
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David Winsemius
Alameda, CA, USA
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