Simple dual-mode drawing program

gistfile1.java

//Craig Pickard
//ICM - Week 2: basic animation
//About this program:
/*
This program contains a button that switches between two modes,
 there is a drawing mode, where a mousePressed event draws a
 collection of circles (defined by random variables) around the mouse pointer.
 clicking the button, and changing modes, spawns a collection of 
 randomly appearing variables.  A mouseclick event enables the eraser,
 which allows the user to erase the circles.  The erasers brush size 
 can be adjusted using the '[' and ']' keys.
 */


//these global variables are shared by all of the different functions, not just draw
boolean click = false;
boolean kp = false;
boolean button = false;
int buttonR = 255;
int buttonG = 0;
int buttonB = 0;
float radius = 50;
float distance;
float brushSize = 15;
float sw = 50;

PFont f; //declaring font datatype for inputting text


void setup() {
  size(1200, 700);
  background(255);
  frameRate(1000);
  f = loadFont("Avenir-Book-48.vlw");
}


void draw() {

  //specify font and size
  fill(255);
  textFont(f, 18);


  //these are the local variables used inside the draw program
  float xSpeed = random(-2, 2);
  float ySpeed = random(-2, 2);
  float x = random(0, width);
  float y = random(0, height);
  float w = random(5, 100);
  float r = random(255);
  float g = random(255);
  float b = random(255);
  float f = random(0, 60);



  //the conditional statement changes the boolean variable 'button'
  //from true to false, or vice versa, if the button is clicked, by
  //calculating the distance between the ellipse's centre, the mouse's
  //XY location and evaluating it against the radius's ellipse to
  //check whether or not the mouse is located within its perimieter
  if (mousePressed && distance < radius) {
    button = !button;
  }


  //this is the code that runs the the eraser program
  if (button) {
    strokeWeight(1);
    noStroke();
    rectMode(CENTER);
    fill(r, g, b, f);
    buttonR = 224;
    buttonG = 72;
    buttonB = 82;
    x += xSpeed;
    y += ySpeed;
    ellipse(x, y, w, w);
    ellipse(x, y, w, w);
    x += 10;
    if (x>width) {
      x=10;
    }
    
        noStroke();
    fill(50, 50);
    rect(1000, 600, 250, 120);
    fill(255);
    textAlign(CENTER);
    text("Click to toggle eraser.", 1000, 580);
    text("Change brush size using", 1000, 610); 
    text("'[' and ']' keys", 1000, 640);

    if (click) {

      fill(255);
      strokeWeight(brushSize);
      stroke(255);
      line(pmouseX, pmouseY, mouseX, mouseY);
      delay(100); //this ensures a smooth transition between program modes
    }
  } else {  //this is the code that runs the circle-drawing program
    noStroke();
    buttonR = 163;
    buttonG = 55;
    buttonB = 63;
    stroke(0);
    if (mousePressed && distance > 200) {
      noStroke();
      fill(r, g, b, f);
      ellipse(mouseX + random(-30, 30), mouseY + random(-30, 30), w/2, w/2);
    }
       noStroke();
    fill(50, 50);
    rect(1000, 600, 250, 120);
    fill(255);
    textAlign(CENTER);
    text("Click and hold the mouse", 1000, 580);
    text("to begin drawing. click", 1000, 610); 
    text("the button to change modes!", 1000, 640);
  }

  //draw the button for switching between programs
  strokeWeight(2);
  stroke(200);
  fill(232);
   ellipse(1100,100,2*radius+20,2*radius+20);
  fill(buttonR, buttonG, buttonB);
  ellipse(1100, 100, 2*radius, 2*radius);
  println(distance + "   " + button);

}

//------------------------------------------------------------

//when the mousePressed function is called, if the mouse pointer is
//over the button, it switches the boolean variable 'button' from true/false
//or else, if it is not within the confines of the button, it simply
//swtiches the boolean variable 'click' from true/false instead
void mousePressed() {
  distance = dist(1100, 100, mouseX, mouseY);
  if (distance < radius) {
    background(255);
    button = !button;
    delay(200); // this ensures a smooth transition between programs
  } else {
    click = !click;
  }
}

// ------------------------------------------------------------

//this function determines the size of the eraser, it can be enlarged
//by pressing the ']' key, or reduced by pressing the '[' key
void keyPressed() {

  brushSize = constrain(sw, 5, 200); //if the brushsize is allowed to go below 0, the program would crash
  if (key == '[') {
    sw -= 5;
  } else if (key == ']') {
    sw += 5;
  }
}
//--------------------------------------------------------