[PATCH 3/3] winex11: Use TINN algorithm to speed up colour lookups.

[Vitaly Budovski]

Vitaliy Margolen wrote:
> Vitaly Budovski wrote:
>   
>> Vitaliy Margolen wrote:
>>     
>> Thanks for the tip. Unfortunately in this instance it will not work as I
>> do in fact query more than a < b. See the nearest function in patch 2.
>>     
> And what is so special about subtracting one from the other?
>
>   

A lot actually. As an example with squared distances: a^2 - b^2 <= c^2.
If a^2 = 27, b^2 = 16, c^2 = 9, then 27 - 16 <= 9 is false. However, if 
we use the square root in distance calculations, sqrt(27) - 4 <= 3 is 
true. As you can see, we get entirely different results.

>> The qsort function I use internally takes that particular function pointer.
>>     
> And the problem is what? Any pointer is compatible with void* (not other
> way around).
>
> Vitaliy Margolen.
>
>   

I get a warning from gcc: passing argument 4 of ‘qsort’ from 
incompatible pointer type.