[R] scalable < > delimiters in plotmath

[baptiste auguie]

Thanks everyone. I've also had a look at plotmath.c where bgroup is
defined for "[", "{", "(", "." but not "<". It seems quite trivial to
add it, at first sight, however there is a part that I don't
understand in the RenderDelim routine,

static BBOX RenderDelim(int which, double dist, int draw, mathContext *mc,
			pGEcontext gc, pGEDevDesc dd)
{

// [... snipped ...]

    case '(':
	top = 230; ext = 231; bot = 232; mid = 0;
	break;
    case ')':
	top = 246; ext = 247; bot = 248; mid = 0;
	break;

These integer codes make no sense to me, I have no clue which ones I
should use for < and >. As far as I understand these codes might
correspond to extended ascii characters whose boundaries and positions
we want to borrow. Then again, maybe it's something else entirely.

Any hints?

Best wishes,

baptiste




On 12 September 2010 03:27, David Winsemius <dwinsemius at comcast.net> wrote:
>
> On Sep 11, 2010, at 9:00 PM, Peter Ehlers wrote:
>
>> On 2010-09-11 16:14, Dennis Murphy wrote:
>>>
>>> Hi Baptiste,
>>>
>>> You need to use the symbol("\nnn") concept, where nnn denotes the octal
>>> symbol number. For<  it's 074 and for>  it's 076. This little test seemed
>>> to
>>> work:
>>>
>>> plot(1, 1, main = expression(symbol("\074")~'x, y'~symbol("\076")))
>>>
>>> HTH,
>>> Dennis
>>
>> It's a matter of taste, but I would use "\341" and "\361".
>> However, these are still not scalable, AFAICS.
>
> Not exactly scalable angles, but you can fake it:
>
> plot(1, 1, main = expression(symbol("\341")~scriptstyle( atop(x,y)
> )~symbol("\361")), cex.main=3)
>
> scriptstyle shrinks the inner atop() material, and since I tested on a Mac
> it should work for Baptiste.
>
> --
> David.
>>
>>  -Peter Ehlers
>>
>>>
>>> On Sat, Sep 11, 2010 at 10:01 AM, baptiste auguie<
>>> baptiste.auguie at googlemail.com>  wrote:
>>>
>>>> What do people use to show angle brackets<  >  in R graphics? Have I
>>>> missed something obvious?
>>>>
>>>> Thanks,
>>>>
>>>> baptiste
>>>>
>>>> On 9 September 2010 17:57, baptiste auguie
>>>> <baptiste.auguie at googlemail.com>  wrote:
>>>>>
>>>>> Dear list,
>>>>>
>>>>> I read in ?plotmath that I can use bgroup to draw scalable delimiters
>>>>> such as [ ] and ( ). The same technique fails with<  >  however, and I
>>>>> cannot find a workaround,
>>>>>
>>>>> grid.text(expression(bgroup("<",atop(x,y),">")))
>>>>>
>>>>> Error in bgroup("<", atop(x, y),">") : invalid group delimiter
>>>>>
>>>>> Regards,
>>>>>
>>>>> baptiste
>>>>>
>>>>> sessionInfo()
>>>>> R version 2.11.1 (2010-05-31)
>>>>> x86_64-apple-darwin9.8.0
>
> David Winsemius, MD
> West Hartford, CT
>
> ______________________________________________
> 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.
>