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wrap number (Read 696 times)
gorgonV
wrap number
Mar 18th, 2010, 4:05am  
Hi,

How do I wrap a number between values, so that if the number exceeds the high value it would start at my provided low value? Similar to constrain()... something like this:

wrap(value, high, low)

wrap(10, 0, 8) //this will wrap the number 10 down to 1
wrap(20, 26, 40) //this will wrap the number 20 up to 31

cheers,
g
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Chrisir
Re: wrap number
Reply #1 - Mar 18th, 2010, 4:26am  


you would have to do :

if (number > valueMax) {number = valueMin;}
else if (number < valueMin) {number = valueMax}

Wink
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gorgonV
Re: wrap number
Reply #2 - Mar 18th, 2010, 4:36am  
Im new to processing, but there should really be a function like this no?:

int wrap(int v, int minv, int maxv )
{
   while(v > maxv) {
   v= -maxv;}
   while(v < minv) {
   v= v+(abs(minv));}
   return v;
}

..or do you usually all users make all these basic functions themselves?

cheers, g

ps
@Chrisir:
your code will clip the value - if the number was 5 above my max value it would just clip down to my min value...
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Cedric
Re: wrap number
Reply #3 - Mar 18th, 2010, 4:40am  
you better use modulo to do that
http://processing.org/reference/modulo.html
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PhiLho 
Re: wrap number
Reply #4 - Mar 18th, 2010, 5:19am  
value = low + value % (high - low + 1);
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davbol
Re: wrap number
Reply #5 - Mar 18th, 2010, 7:45am  
PhiLho  wrote on Mar 18th, 2010, 5:19am:
value = low + value % (high - low + 1);


nicely and concisely expressed :)
...tho except when 'value' is negative, since java's % is a remainder operator not a true modulo as used in "modular arithmetic".  fe try wrapping -15 into 0,10 --> -4, just something to be aware of.
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