R help - Nov 2013 - can par()$pin be used to guarantee equal horizontal and vertical image lengths?

Today at 10:03 AM  
I use several different versions of R, including RGui on Windows and 
rstudio on Linux.  In all cases, I use graphical commands, such as 
image().  

image() displays rectangles, but I want to be able to 
guarantee that the heights of those rectangles will always equal the 
widths.  Typically, the rectangles come out with notable asymmetries.

Thus, if I need to draw a perfect circle with square pixels, I usually get a
squashed ellipse with oblong pixels.

I had hoped that par()$pin would be the answer, but I can't seem to set it
properly.  For example:
> par()$pin
[1] 4.416111 1.685556
> source('~/.active-rstudio-document')
> par()$pin<-c(4,4)
Error in par()$pin <- c(4, 4) : invalid (NULL) left side of
assignment
> str(par()$pin)
 num [1:2] 4.46 2.82
> par()$pin[2]<-par()$pin[1]
Error in par()$pin[2] <- par()$pin[1] : 
  invalid (NULL) left side of assignment

I
 have experimented with other commands, and I don't need to continue to 
use image() if some other command would be more suitable.

Thanks.
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How about using the asp option?  For example,

A <- matrix(rnorm(200),20)
image(A, asp=ncol(A)/nrow(A))

-tgs


On Tue, Nov 19, 2013 at 3:56 AM, Mercutio Florid
<floridmercutio@yahoo.com>wrote:
>
> Today at 10:03 AM
> I use several different versions of R, including RGui on Windows and
> rstudio on Linux.  In all cases, I use graphical commands, such as
> image().
>
> image() displays rectangles, but I want to be able to
> guarantee that the heights of those rectangles will always equal the
> widths.  Typically, the rectangles come out with notable asymmetries.
>
> Thus, if I need to draw a perfect circle with square pixels, I usually get
> a squashed ellipse with oblong pixels.
>
> I had hoped that par()$pin would be the answer, but I can't seem to set
it
> properly.  For example:
> > par()$pin
> [1] 4.416111 1.685556
> > source('~/.active-rstudio-document')
> > par()$pin<-c(4,4)
> Error in par()$pin <- c(4, 4) : invalid (NULL) left side of assignment
> > str(par()$pin)
>  num [1:2] 4.46 2.82
> > par()$pin[2]<-par()$pin[1]
> Error in par()$pin[2] <- par()$pin[1] :
>   invalid (NULL) left side of assignment
>
> I
>  have experimented with other commands, and I don't need to continue to
> use image() if some other command would be more suitable.
>
> Thanks.
>         [[alternative HTML version deleted]]
>
>
> ______________________________________________
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>
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