// color = map(par,min1,max1,min2,max2);

// min1 - max1 is the range of the variable par

// and we want to map it to the range min2 - max2

​

let r = 100;

let g = 100;

let b = 100;

​

function setup() {

  createCanvas(400, 400);

}

​

​

​

function draw() {

  background(r,g,b);

  r = map(mouseX,0,400,0,255);

  g = map(mouseX+mouseY,0,800,0,255);

  b = map(mouseY,0,400,0,255);

  fill(200,100,200);

  circle(mouseX,mouseY,20);

}