[Rd] Re: argument srt for mtext(); was: [R] using text on the x axis ticks rather than numbers

[Uwe Ligges]

Marc Schwartz wrote:

> On Wed, 2004-09-08 at 03:13, Uwe Ligges wrote:
> 
>>Prof Brian Ripley wrote:
>>
>>
>>>On Wed, 8 Sep 2004, Prof Brian Ripley wrote:
>>>
>>>
>>>
>>>>On Wed, 8 Sep 2004, Uwe Ligges wrote:
>>>
>>>
>>>[...]
>>>
>>>
>>>
>>>>>Indeed, I think it is possible to provide an srt command (e.g. in half a 
>>>>>year for something like R-2.1.0). What is expected for "srt = 0"?
>>>>>a) the current behaviour, i.e. srt=0 in respect to the las setting *and* 
>>>>>the margin side to plot the text in, or
>>>>>b) always horizontally drawn text?
>>>>>
>>>>>I'd vote for b).
>>>>
>>>>That's easy, see the precedent in
>>>>
>>>>
>>>>
>>>>>>BTW, if you want to use srt with mtext(at=) you can always use S ....
>>>>
>>>>S ignores las if at= is set, so srt=0 is the current default behaviour.
>>>
>>>
>>>Sorry, I garbled that.  In S, srt=0 is horizontal whatever side=, and las
>>>is always ignored.  Not that that is documented AFAICS, and it is hard to
>>>remember ....
>>>
>>>[...]
>>>
>>
>>Since S is different for mtext() anyway:
>>We can say that adjustment is determined automatically by las + side, as 
>>it already is, and has to be adapted by the user if required.
>>
>>Uwe
> 
> 
> 
> Perhaps this is because I have only had one cup of coffee so far this
> morning, but is the bias at this point towards making the change or not
> making the change? I'm a little confuzzled...

As Brian already pointed out, you are not the only "confuzzled" one ... 
  at least one of the other "confuzzled" people here has not decided 
anything yet. ;-)
If someone is going to force a decision and convinces me, I'll probably 
try to provide a patch.

The most problematic point (mentioned by Brian Ripley) is the automatic 
settings of the "adj" and "padj" values (related to reading direction, 
as of R-2.0.0 alpha). Both have good defaults for parallel and 
perpendicular text (related to axis) now, but what happens if srt is 
set, and in particluar what happens if
   (srt %% 90) != 0
My suggestion is to use the default settings for *adjustment* ("adj" and 
"padj") derived from "las" and "side" as usual - even if *rotation* is 
no longer derived from "las" and "side".

Uwe


> If it is towards making the change, I would vote for an explicit 'srt'
> to override 'las' as per Uwe's option "b" and Prof. Ripley's last
> comment. That would seem to me to be quite logical at first glance.
> 
> In either case, as a possible option, I could draft some text for a FAQ
> on this issue of rotated axis labels, since it seems to get asked often,
> and send it to Kurt.
> 
> Let me know.
> 
> Marc
>