[Rd] Is text(..., adj) upside down? (Or am I?)

[Prof Brian Ripley]

On Tue, 22 Jul 2008, S Ellison wrote:

> ?text says
>    "'adj' allows _adj_ustment of the text with respect to '(x,y)'.
>     Values of 0, 0.5, and 1 specify left/bottom, middle and
> right/top,
>     respectively."
>
> But it looks like 0, 1 specify top, bottom respectively in the y
> direction.
>
> plot(1:4)
> text(2,2, "adj=c(0,0)", adj=c(0,0))
> text(2,2, "adj=c(0,1)", adj=c(0,1), col=2) #the red one's below the
> black one...

If that comment is what you see (and I do on X11), it is as documented. In 
the first text() call the left bottom of the text box is at the specified 
point. In the second text() call the left top of the text box is at the 
specified point, so the text box should be lower.

> #x-adj is OK
> text(3,3, "adj=c(0,0)", adj=c(0,0))
> text(3,3, "adj=c(1,0)", adj=c(1,0), col=2)
>
> [I am using r 2.7.1 in windows; adj behaviour is consistent in 2.6.0ff
> and for expressions as well as text]

All 'vertical' adjustment is done in the graphics engine: some 
'horizontal' adjustment is done in the devices.

> Perhaps a two-word correction to ?text ?

'adjustment' is not well-defined for text position, whereas 'alignment' or 
'justification' are, so I suggest adding one of those before 
'respectively'.

>
> Steve Ellison
> Lab of the Government Chemist
> UK
>
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-- 
Brian D. Ripley,                  ripley at stats.ox.ac.uk
Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
University of Oxford,             Tel:  +44 1865 272861 (self)
1 South Parks Road,                     +44 1865 272866 (PA)
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