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From: Malcolm McLean <malcolm.arthur.mclean@gmail.com>
Newsgroups: comp.lang.c
Subject: Re: filling area by color atack safety
Date: Tue, 19 Mar 2024 11:41:45 +0000
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On 19/03/2024 05:54, Tim Rentsch wrote:
> Malcolm McLean <malcolm.arthur.mclean@gmail.com> writes:
> 
>> On 18/03/2024 09:30, Tim Rentsch wrote:
>>
>>> Michael S <already5chosen@yahoo.com> writes:
> [...]
>>>> Except I don't understand why it works it all.
>>>> Can't fill area have sub-areas that only connected through
>>>> diagonal?
>>>
>>> It is customary in raster graphics to count pixels as adjacent
>>> only if they share an edge, not if they just share a corner.
>>> Usually that gives better results;  the exceptions tend to need
>>> special handling anyway and not just connecting through
>>> diagonals.
>>
>> Though with a binary image, if the foreground is 4-connected, the
>> background must therefore be 8-connected.
> 
> It might be but it doesn't have to be.
> 
> Also different terminology should be used, since 4-connected
> (also N-connected, for other integer N) has a specific meaning in
> graph theory, and one very different than what is meant above.

That is the terminology in binary image processing. The pixels are 
4-connected or 8-connected depending on whether a shared corner is 
considered to make the group of pixels two objects or one object.

-- 
Check out Basic Algorithms and my other books:
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