I've been trying to have a button (Arduino) change the fill color of an ellipse in Processing 3. I thought an if statement like if(button == 0){ if(fillValue == rgb){ fill(0,0,0);}or something more or less. So if some one has the awnser please help.

To me this is deeper than one line of code. From the beginning of time (as in when I began to code GUI things) I would have code to set up the button's event handler then some function that would be called to do what I wanted when the event happened.

Your one liner looks incomplete and ineffective. Remember that this forum rarely supplies a working code passage so share your work so far along with if you are using that "processing" javascript system.

And perhaps it's a better idea to ask this at the Arduino forum to get a quicker answer, because I really had to google what Arduino was :)
https://forum.arduino.cc/

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