[Rd] strange behavior from cex="*"

[Uwe Ligges]

On 18.11.2011 10:14, Patrick Burns wrote:
> Someone ambitious could find problems like
> this using random input testing like I talked
> about at useR last summer.
>
> http://www.burns-stat.com/pages/Present/random_input_test_annotated.pdf
>
> Testing graphics would be more labor intensive
> than the testing I do, but you could think of it
> as a video game.

See also the graphicsQC package.

Uwe

> On 17/11/2011 00:29, Duncan Murdoch wrote:
>> On 11-11-16 5:26 PM, Ben Bolker wrote:
>> > -----BEGIN PGP SIGNED MESSAGE-----
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>> > On 11-11-16 05:18 PM, peter dalgaard wrote:
>> >>
>> >> On Nov 16, 2011, at 22:38 , Ben Bolker wrote:
>> >>
>> >>> Someone inquired on StackOverflow about apparently non-deterministic
>> >>> graphics behaviour in R. I noticed that they were using cex="*" and
>> >>> discovered some potentially weird behavior.
>> >>
>> >> It can be reproduced much more simply (well, not the hang, but bad
>> >> enough):
>> >>
>> >> In a plain R application console (OSX Snow Leopard),
>> >>
>> >> for (i in 1:100) plot(1:10,cex="*")
>> >>
>> >> will _sometimes_ show big circles, indicating random data being
>> >> picked up.
>> >>
>> >> The "cex" is by definition numeric, so you can't expect to be able to
>> >> pass a character string, but the code should check.
>> >
>> > Looks (?) like the check could go in FixupCex (which already tests for
>> > isReal, isInteger, and isLogical) in src/main/plot.c , unless there
>> is a
>> > wish to catch it earlier/in R code.
>>
>> Yes, that's where the check was missed. I'll fix it. The other
>> parameters appear to have been checked properly.
>>
>> > It's mildly surprising to me that people can continue to find odd
>> > cases like this after more than 10 years (and imagine how many
>> > cumulative hours of R use ...) [I'm assuming that this hole has been
>> > present for a log time: I don't have the patience to do the SVN
>> > archaeology to find out how long.]
>>
>> So now you can prove me wrong about the other parameters...
>>
>> Duncan Murdoch
>>
>>
>> >
>> >>
>> >>>
>> >>> On repeated runs of the same code I can get different PNGs. If I set
>> >>> the number of runs high enough, I seem to be able to get R to hang.
>> >>> If I do a single version plotting to an interactive graphics window I
>> >>> can get the point sizes to jump around as I resize the window
>> (someone
>> >>> reported being able to reproduce that behaviour in the Windows GUI
>> >>> as well).
>> >>>
>> >>> This is clearly a user error, but non-deterministic behaviour (and
>> >>> hanging) are a little disturbing.
>> >>>
>> >>> I haven't had a chance yet to try to dig in and see what's happening
>> >>> but thought I would report to see if anyone else could
>> reproduce/figure
>> >>> it out.
>> >>>
>> >>> Ben Bolker
>> >>>
>> >>>
>> >>> ########################
>> >>> ## n<- 100 ## hangs R
>> >>>
>> >>> n<- 33
>> >>>
>> >>> fn<- paste("tmp",seq(n),"png",sep=".")
>> >>> for (i in seq(n)) {
>> >>> png(fn[i])
>> >>> plot(1:10,1:10,cex="*");
>> >>> dev.off()
>> >>> }
>> >>>
>> >>> ff<- subset(file.info(fn),select=size)
>> >>> ff<- ff[!duplicated(ff$size),,drop=FALSE]
>> >>> table(ff$size)
>> >>> require(png)
>> >>> pngs<- lapply(rownames(ff),readPNG)
>> >>>
>> >>> png.to.img<- function(x) matrix(rgb(x[,,1],x[,,2],x[,,3]),
>> >>> nrow=dim(x)[1],ncol=dim(x)[2])
>> >>>
>> >>> imgs<- lapply(pngs,png.to.img)
>> >>>
>> >>> par(mfrow=c(2,2))
>> >>> lapply(imgs,function(x) {
>> >>> plot(0:1,0:1,type="n",ann=FALSE,axes=FALSE)
>> >>> rasterImage(x,0,0,1,1)
>> >>> })
>> >>>
>> >>> #########################
>> >>>
>> >>>> sessionInfo()
>> >>> R Under development (unstable) (2011-10-06 r57181)
>> >>> Platform: i686-pc-linux-gnu (32-bit)
>> >>>
>> >>> attached base packages:
>> >>> [1] stats graphics grDevices utils datasets methods base
>> >>>
>> >>> other attached packages:
>> >>> [1] glmmADMB_0.6.5 MASS_7.3-14 png_0.1-3
>> >>>
>> >>> loaded via a namespace (and not attached):
>> >>> [1] grid_2.15.0 lattice_0.19-33 nlme_3.1-102 tools_2.15.0
>> >>>
>> >>> ______________________________________________
>> >>> R-devel at r-project.org mailing list
>> >>> https://stat.ethz.ch/mailman/listinfo/r-devel
>> >>
>> >
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