Greetings

I'm quite new to processing and ran into trouble with using the ControlP5 library.
I'm still in the state of experimenting and tried to change the controlP5-basic example.

I wanted to make a toggle-button that changes the transparency of every element. Including the button.

Code:

import controlP5.*;

ControlP5 controlP5;

int visOpaque = 255;
int ColorSquare = 200;
int ColorRect = 0;
int ColorBackground = 100;
int ColorToggle = color(253,228,55, visOpaque);
int ColorActive = color(244,249,250);
boolean globalTrans = false;


void setup() {
  size(400,200);
  frameRate(25);
  controlP5 = new ControlP5(this);
  controlP5.addToggle("toggleGlobalTrans",true,10,10,40,40).setColorActive(ColorActive);
}

void draw() {
  background(ColorBackground);
  fill(ColorSquare);
  rect(200,50,100,100);
  fill(ColorRect,visOpaque);
  rect(0,0,width,100);
}

void toggleGlobalTrans(boolean globalTrans) {
  if(globalTrans==false) {
    visOpaque = 200;
    controlP5.setColorForeground(ColorToggle); //<--- ???
  } else {
    visOpaque = 255;
    controlP5.setColorForeground(ColorToggle);
  }
}
 

But I don't know how to give the changed color-value to the controlP5-controller because it needs integer-values.

I hope I could discribe the problem so you get what I mean & of course that the question is not that stupid.

As I said I'm a real beginner  

Thank you. That's what I meant.
Wasn't that difficult. Now I feel kind of stupid asking such a simple thing.
The color() int() thing is confusing to me.
println() says colorBlu = -16755201 after the color is transformed to integer, right?
But nevertheless I'm one step closer to the goal. And I think it's gonna be fun.

Thx again

actually your question is not trivial at all, since color is its own datatype. To see how it works, you can look in the reference here: http://processing.org/reference/color_datatype.html
As for your second question, of course you can, among a million other things. At this stage, I would suggest you switch off the computer, take pencil and paper, and draw a flowchart of what your programm will be doing. You will see it all becomes clear. Also a good book to get you started and more, is "Processing: A Programming Handbook for Visual Designers and Artists". It's on the processing homepage, the book with the blue cover. I enjoy it a lot.