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Topic: comparing colors (Read 617 times) |
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der_rabe
 
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comparing colors
« on: Feb 17th, 2004, 4:10pm » |
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is there a way to compare colors. like:
if whateverColor == referenceColor
this does not work,but how can i do it?
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Bernd Salewski
student of digital media
Hochschule Bremen
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mKoser
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Re: comparing colors
« Reply #1 on: Feb 17th, 2004, 4:55pm » |
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this works:
Code:
color c1, c2;
void setup(){
c1 = color(255, 0, 0);
c2 = color(255, 0, 0);
}
void loop(){
}
void mousePressed(){
if(c1 == c2){
println("colors match");
}else{
println("colors don't match");
}
}
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try changing the values of c1 and c2 (to not match) and run the code again.
+ mikkel
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mikkel crone koser | www.beyondthree.com | http://processing.beyondthree.com
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der_rabe
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ok
« Reply #2 on: Feb 17th, 2004, 6:25pm » |
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so it works, ok, i guess i have to look into my code again, to find out, why it does not work as a want it to.
my head is soo dumb today  (got a cold, haatschii!)
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Bernd Salewski
student of digital media
Hochschule Bremen
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rgovostes
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Re: comparing colors
« Reply #3 on: Feb 18th, 2004, 5:37am » |
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A color is just a 4 byte integer, isn't it? You should be able to do comparisons like > and <= if you were so inclined.
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benelek
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Re: comparing colors
« Reply #4 on: Feb 19th, 2004, 11:47am » |
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a color (as in the data type color) is a 32-bit integer (just like an int).
the 32 bits are divided up into four lots of 8 bits, in order to store color component information. it works like this:
Code:
AAAAAAAA RRRRRRRR GGGGGGGG BBBBBBBB
//A = Alpha
//R = Red
//G = Green
//B = Blue
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and of course, an 8-bit number goes from 0 to 256, which is why you define your RGB numbers in components within that range.
because the components are stored in bit locations rather than in some decimal fashion, you can't use >= or <= on the whole color variable.
however, if you know how to use bit-shifting to get to the components, you can use >= or <= on those RGB components. if you don't know what the hell i'm on about, you can use the red(), green() and blue() methods to look at the color components 
hopefully helpful,
~Jacob
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