Re: [boost] VIGRA and GIL -- Review of Generic Image Library (GIL)

From: Ullrich Koethe (koethe_at_[hidden])
Date: 2006-10-17 12:34:48

Lubomir Bourdev wrote:
>>The fact that GIL doesn't provide campling makes me argue it 
>>is not a mature library. It's such a basic need (I get this 
>>from reading the book!)
>>
> 
> 
> To clamp a channel in GIL you can just say:
> 
> T channel;
> T clamped = std::min(channel, channel_max_value<T>());
> 

But that's not how things work in practice. When the data are already 
stored as type T, overflow has already occured. Moreover, the possibility 
of overflow typically arises deep inside some algorithm, where you cannot 
simply call std::min(), but need another mechanism (e.g. promotion traits).

Ulli

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| Ullrich Koethe  Universitaet Hamburg / University of Hamburg   |
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