dimmer button draft

my code


// Dimmer Button
// I have a feeling this fade could be done better...

// declare and initialize variables
boolean button = false;
int x = 50;
int y = 50;
int w = 100;
int h = 75;
float change = 5; // fade rate
float gs; //greyscale from 0-255

void setup() {
size(200,200);
}

void draw() {
background(gs);
stroke(255);

// if mouse is pressed over the button
if (mouseX > x && mouseX < x+w && mouseY > y && mouseY < y+h && mousePressed) { button = true; } else { button = false; } // this is the fade if (button) { change = -5; fill(255,0,0); } else { change = 5; fill(0,0,255); } background(gs); rect(x,y,w,h); gs = gs + change; // this creates the fade // declaring my constraints gs = constrain(gs,0,254); }