createCanvas(600, 400);

  background(10);

}

​

function draw() {

  r= map(mouseX, 0, 600, 255, 0);

   g= map(mouseY, 0, 300, 0, 255);

   b= map(mouseX, 0, 200, 0, 255);

   a = map (mouseY,0,400, 0,255);

    x= map (mouseX,0, 600, 10,70);

    y=  map (mouseY, 0,400, 70,10);

  noStroke();

  fill (r,g,b,a);

  ellipse (mouseX, mouseY, x, y);

}

​

​