Re: [Groff] Integral signs

[Bob Diertens]

On Wed, Feb 28, 2007 at 01:42:38PM +1100, Miklos Somogyi wrote:
> Dear Folks,
> 
> I need some integral signs with circles/ellipses around them (e.g. for 
> control volumes).
> I've experimented a lot but only got something that is just acceptable 
> in print,
> but downright ughhly in Preview and Acrobat.
> 
> How would you stretch the circle of the double- and triple integrals?
> I've tried \(ci  instead of `o' but it looks very thin compared to 
> thick int signs.
> What can you suggest (espec something scalable)?

Use \D'e X Y' for the ellips.
The example below looks good in print and decent in a previewer.

---
.EQ
delim $$
define oint % type "operator" vcenter size +5 "\v'-0.2m'\D'e 0.4m 
0.4m'\v'0.2m'\h'-0.2m-(\w'\(is'u/2u)'\v'0.2m'\(is\v'-0.2m'" %
define oiint % type "operator" vcenter size +5 "\v'-0.2m'\D'e 
0.4m+(\w'\(is'u-0. 05m) 
0.4m'\v'0.2m'\h'-0.2m-((\w'\(is'u-0.05m)/2u)-((\w'\(is\(is'u-0.05m)/2u)'\v'0.2m'\(is\h'-0.05m'\(is\v'-0.2m'"
 %
define oiiint % type "operator" vcenter size +5 "\v'-0.2m'\D'e 
0.4m+(\w'\(is\(is'u-0.10m) 
0.4m'\v'0.2m'\h'-0.2m-((\w'\(is\(is'u-0.10m)/2u)-((\w'\(is\(is\(is'u-0.10m)/2u)'\v'0.2m'\(is\h'-0.05m'\(is\h'-0.05m'\(is\v'-0.2m'"
 %
.EN
.sp 3
$oint x + y$ $size +2 { oint x + y }$ $size +4 { oint x + y }$ $size +8 { oint 
x + y }$ $size +16 { oint x + y }$
.sp 3
$oiint x + y$ $size +2 { oiint x + y }$ $size +4 { oiint x + y }$ $size +8 { 
oiint x + y }$ $size +16 { oiint x + y }$
.sp 3
$oiiint x + y$ $size +2 { oiiint x + y }$ $size +4 { oiiint x + y }$ $size +8 { 
oiiint x + y }$ $size +16 { oiiint x + y }$
---

Gr,
    Bob