[R] problem with symbol function

[Duncan Murdoch]

On 27/04/2009 5:23 PM, Christophe Dutang wrote:
> so it could be a limitation of graphics on windows?

It's not graphics on Windows, but it appears to be a limitation of the 
windows() graphics device in R.  It is used for bitmap plots as well as 
on-screen plots, which is why you saw the same effect in jpeg, but 
different devices are used for Postscript and PDF.

When drawing lines, R handles the dash style itself, rather than using 
the built-in dashes.  But it doesn't do so for circles, and doesn't make 
use of the Windows line styles.

If you really need the dashes onscreen, you can draw the circle 
yourself.  Assuming the scales are equal on both axes that's easy, just use

 > theta <- seq(0,2*pi, len=256)
 > lines(x+r*cos(theta), y+r*sin(theta), lty="dashed")

(where (x,y) is the center and r is the radius).  It's more work if you 
want things to appear as circles when the scales are unequal, but I 
think this works:

circle <- function(x, y, inches=1, ...) {
   theta <- seq(0, 2*pi, len=256)
   lines(x + grconvertX(inches*cos(theta), "inches", "user") - 
grconvertX(0, "inches", "user"),
         y + grconvertY(inches*sin(theta), "inches", "user") -
grconvertY(0, "inches", "user"),
         ...)
}

so you'd get the plot you wanted using

circle(0, 0, inches = 1.5, fg="black",lty="dashed")

The circle function is not vectorized, so it's not as useful as symbols, 
but it could be improved.

Duncan Murdoch


> 
> It also appears with "long dash" lines.
> 
> x <- -4:4
> y <- -4:4
> 
> plot(x,y,type="n")
> 
> symbols(0, 0, add = TRUE, circles = 1, inches = 1, fg="black",  
> lty="solid")
> 
> symbols(0, 0, add = TRUE, circles = 1, inches = 2,  
> fg="black",lty="dashed")
> 
> symbols(0, 0, add = TRUE, circles = 1, inches = 3,  
> fg="black",lty="longdash", lwd=2)
> 
> 
> Le 27 avr. 09 à 23:07, Joshua Wiley a écrit :
> 
>> I read that the lty=2 argument does not work on all graphics  
>> devices. You might double check that since it works on mac.
>>
>>
>> Joshua Wiley
>>
>>
>>
>> ---- Original message ----
>>> Date: Mon, 27 Apr 2009 22:58:11 +0200
>>> From: Christophe Dutang <dutangc at gmail.com>
>>> Subject: Re: [R] problem with symbol function
>>> To: Joshua Wiley <jwile004 at ucr.edu>
>>> Cc: r-help at r-project.org
>>>
>>> This point is ok if I download R from the Austrian mirror. R is
>>> properly install on both computers. I also get this strange behavior
>>> with R 2.7.2. There is something I'm missing...
>>>
>>>
>>> Le 27 avr. 09 à 22:54, Joshua Wiley a écrit :
>>>
>>>> I am running SP3. You said earlier that you were having trouble
>>>> downloading 2.9.0, are you sure everything downloaded and installed
>>>> properly? There have been some questions about transitioning to the
>>>> new build going around.
>>>>
>>>> Joshua Wiley
>>>>
>>>>
>>>>
>>>> ---- Original message ----
>>>>> Date: Mon, 27 Apr 2009 22:45:26 +0200
>>>>> From: Christophe Dutang <dutangc at gmail.com>
>>>>> Subject: Re: [R] problem with symbol function
>>>>> To: Joshua Wiley <jwile004 at ucr.edu>
>>>>> Cc: r-help at r-project.org
>>>>>
>>>>> what is your service pack version?
>>>>>
>>>>> at home I use the SP2 version.
>>>>>
>>>>> Le 27 avr. 09 à 22:29, Joshua Wiley a écrit :
>>>>>
>>>>>> Hi Christophe,
>>>>>>
>>>>>> I am able to plot dashed circles on Windows. I'm afraid I do not
>>>>>> have any suggestions for you. What happens when you try to plot it
>>>>>> on Windows?
>>>>>>
>>>>>>
>>>>>> Joshua Wiley
>>>>>>
>>>>>>
>>>>>> ---- Original message ----
>>>>>>> Date: Mon, 27 Apr 2009 22:15:53 +0200
>>>>>>> From: r-help-bounces at r-project.org (on behalf of Christophe
>>>>>>> Dutang <dutangc at gmail.com
>>>>>>>> )
>>>>>>> Subject: [R] problem with symbol function
>>>>>>> To: r-help at r-project.org
>>>>>>>
>>>>>>> Hi all,
>>>>>>>
>>>>>>> I use the symbol functions to draw circles. But the argument lty
>>>>>>> does
>>>>>>> not work on windows but works correctly on my macbook:
>>>>>>>
>>>>>>> x <- -4:4
>>>>>>> y <- -4:4
>>>>>>>
>>>>>>> plot(x,y,type="n")
>>>>>>>
>>>>>>> symbols(0, 0, add = TRUE, circles = 1, inches = 1, fg="black",
>>>>>>> lty="solid")
>>>>>>>
>>>>>>> symbols(0, 0, add = TRUE, circles = 1, inches = 2, fg="black",
>>>>>>> lty="dashed")
>>>>>>>
>>>>>>>
>>>>>>> The second circle should be drawn with dash... it works on my
>>>>>>> macbook
>>>>>>> but on my PC.
>>>>>>>
>>>>>>> I use R 2.9.0 on windows xp home and mac os 10.5.
>>>>>>>
>>>>>>> Does anyone have this problem? is it a limitation of windows?
>>>>>>>
>>>>>>> thanks in advance
>>>>>>>
>>>>>>>
>>>>>>> Christophe
>>>>>>>
>>>>>>> --
>>>>>>> Christophe Dutang
>>>>>>> Ph. D. student at ISFA, Lyon, France
>>>>>>> website: http://dutangc.free.fr
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>> 	[[alternative HTML version deleted]]
>>>>>>>
>>>>>>> ______________________________________________
>>>>>>> R-help at r-project.org mailing list
>>>>>>> https://stat.ethz.ch/mailman/listinfo/r-help
>>>>>>> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
>>>>>>> and provide commented, minimal, self-contained, reproducible  
>>>>>>> code.
>>>>> --
>>>>> Christophe Dutang
>>>>> Ph. D. student at ISFA, Lyon, France
>>>>> website: http://dutangc.free.fr
>>>>>
>>>>>
>>>>>
>>>>>
>>> --
>>> Christophe Dutang
>>> Ph. D. student at ISFA, Lyon, France
>>> website: http://dutangc.free.fr
>>>
>>>
>>>
>>>
> 
> --
> Christophe Dutang
> Ph. D. student at ISFA, Lyon, France
> website: http://dutangc.free.fr
> 
> 
> 
> 
> 
> 	[[alternative HTML version deleted]]
> 
> 
> 
> ------------------------------------------------------------------------
> 
> ______________________________________________
> R-help at r-project.org mailing list
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> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.