Thanks, Bo, that gets me on a bit!
On Sat, May 12, 2012 at 8:36 PM, Bo Jacoby <bojac...@yahoo.dk> wrote:
> The winding number program is written and tested, and does not assume the
> polygon to be convex.
>
> rd=.(**|)&.+. NB. round complex number
> W=.rd@(%&0j2p1)@(+/)@:^.@(% _1&|.)NB. winding number
> p=.0j1^i.4 NB. test polygon
> rd p NB. display test polygon vertices
> 1 0j1 _1 0j_1
> load'plot'
>
> plot (,{.)p NB. show polygon
> W p-2 NB. 2 is outside polygon
> 0
> W p-0 NB. 0 is inside polygon
> 1
>
>
>
>
>
>>________________________________
>> Fra: Ian Clark <earthspo...@gmail.com>
>>Til: Programming forum <programming@jsoftware.com>
>>Sendt: 17:38 lørdag den 12. maj 2012
>>Emne: Re: [Jprogramming] Irregularly shaped buttons
>>
>>Thanks, everyone. Plenty of ideas here.
>>
>>Lazy me: I was angling for some written & tested code. But at least I
>>know I won't be wasting my time reinventing the wheel.
>>
>>The "polygon" can't be assumed convex. In fact, since I'd like to
>>accommodate the most general shape, I'm going with either a binary
>>pixel mask (the crudest, easiest solution) or detecting the underlying
>>pixel color upon mouseclick.
>>
>>
>>On Fri, May 11, 2012 at 5:41 PM, Ian Clark <earthspo...@gmail.com> wrote:
>>> To save me reinventing the wheel, has anybody written routines to act
>>> on mouseclicks inside irregularly-shaped "buttons"?
>>>
>>> Techniques I'm considering:
>>>
>>> ++ Detecting if a point is inside an arbitrary polygon
>>>
>>> ++ Unions and differences of rectangles, triangles and sectors
>>>
>>> ++ Color of the pixel under the cursor
>>>
>>> If it works on a simple map of the USA, it'll probably work for my purpose.
>>----------------------------------------------------------------------
>>For information about J forums see http://www.jsoftware.com/forums.htm
>>
>>
>>
> ----------------------------------------------------------------------
> For information about J forums see http://www.jsoftware.com/forums.htm
----------------------------------------------------------------------
For information about J forums see http://www.jsoftware.com/forums.htm
