[PATCH 3/3] winex11: Use TINN algorithm to speed up colour lookups. (try 2)

[Vitaly Budovski]

Dmitry Timoshkov wrote:
> "Vitaly Budovski" <vbudovski at gmail.com> wrote:
>
>>> Now that you got rid of sqrt calls usage of float numbers internally
>>> doesn't look justified (to me) anymore.
>>>
>>
>> Only because in this instance it is used with integer data. It 
>> doesn't need to be limited to just integer values. Besides, what 
>> would be gained by changing it to integers as you suggest?
>
> What would be gained is an additional speed. Since this code is supposed
> to be used to handle palette/color data there is no need to use floats at
> all.
>

As I explained previously, this algorithm makes no assumptions about the 
data that is being queried. Just because in this case (patch 3) we are 
working with RGB colour data doesn't mean it is limited to only that. It 
will work with *any* values, as long as you can provide an appropriate 
distance function. For this reason, I do not think that limiting the 
distances to integer values makes much sense. Getting rid of the square 
root has some benefit because it is generally an expensive operation. I 
do not think that getting rid of floats would give any noticeable 
performance improvements.