[R] Aspect ratio and limits

[Marc Schwartz]

On Tue, 2005-04-19 at 17:40 +0100, Barry Rowlingson wrote:
> Marc Schwartz wrote:
> 
> > # Set height value as you require
> > height <- 3
> > X11(width = aspect * height, height = height)
> > .... 
> > Does that get you what you need?
> 
>   I'm guessing that will work, but it just seems unsatisfactory, since 
> if I resize my graphics window I mess it up.

Patient: "Doctor, when I move my arm like this it hurts."

Doctor: "Well...stop moving your arm like that."

;-)

I think that unlike your lattice example below, the X11 device is
"elastic" on a resize. I do not see a par() setting that alters that
behavior.

For some reason, I think that under Windows there was a setting for the
default Windows graphics device relative to resizing, but that my be the
result of a TIA and not the representation of reality...I hate it when
that happens.  :-)

>   If I set par(pty='s') I can have a square plot floating inside a 
> graphics window of any shape, I'd like to be able to plot something 
> specifying ylim and asp and get a rectangular plot with a fixed aspect 
> ratio floating around inside a resizable graphics device....
> 
>   The 'aspect' ratio of xyplot (lattice package) lets you specify the 
> aspect ratio of the plot (not relating to the data, ie aspect=1 draws a 
> square plot whatever the ratio of X and Y range). Try this:
> 
>   xy=data.frame(x=c(0,21),y=c(0,4))
>   xyplot(y~x,data=xy,aspect=0.2)
> 
>   - now resize the graphics window and the plot keeps its ratio. That's 
> the effect I was hoping to get from base graphics.
> 
>   I could use lattice graphics but I'd have to work out the value of 
> 'aspect' to get the 1:1 aspect ratio for my data. I'm not sure this is 
> trivial, since it may involve considering the various margins and 
> spacing around a plot.
> 
>   Close...

There is a fair amount of interaction there. I am not sure what might be
a "best" approach. I'll think about it. If I come up with anything, I'll
let you know.

I guess that one underlying consideration I might think about here is,
where is your final output going. If to a PS file for printing or
inclusion in a LaTeX document, I would focus on how the plot looks
there, especially when trying to compare it to X11 output.

Marc