# [OT] Poll: What does it mean for 1 rect to be 'within' a certain distance of another rect?

David V Glasgow dvglasgow at gmail.com
Tue Feb 16 13:02:24 EST 2021

```Well, my suggestion a non starter if you need to do hard sums, and you eschew invisibles.

However, my thinking was this... I understood that the task was to detect when two rectangles r1 and r2 were within distance d of each other.   Presumably ether a flat bit or a pointy bit, coming in at any angle.  if each rectangle is centred and grouped with a rect that is bigger by d/2, any intersection of any two bigger rects means that the smaller corresponding r1 and r2 rects are at or within the desired distance d (half d measured by r1’margin over r1, and half by r2’margin over r2). The size of the groups is ignored, and as long as all r & r’ stay centred it should work, unless the rects move super quickly.

Oh.  It just occurred to me is that the bigger rects would have to have rounded corners.  Hmmm.

OK, I’ll just sit back and see how it should be done.

Cheers

David G

> On 16 Feb 2021, at 5:08 pm, Paul Dupuis via use-livecode <use-livecode at lists.runrev.com> wrote:
>
> On 2/16/2021 6:16 AM, David V Glasgow via use-livecode wrote:
>> Being a bear of little brain, I would try placing each rect into a group centred on a larger rect, where the margin is d/2,  then test using intersect.
>>
>> Now, where did I put that hunny?
>>
>>
>
> Like the pooh reference!
>
> Although I am not sure I follow exactly what you are suggests - AND - I need to do this via math rather than visible (or invisible) objects in LC.
>
> for rects r1,r2, I have l1,t1,r1,b2 and l2,t2,r2,b2 for their coordinates. The rect min(l1,l2),min(t1,t2),max(r1,r2),max(b1,b2) is a rectangle that exactly bounds both rects - this would be the rect of the group (if you created them as objects and grouped them (less margins/borders).
>
> I don't follow the part about 'centered on a larger rect where the margin is d/2?
>
>
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```