Quick and easy multi monitor (1080p) multi photo slideshow in Processing 3.0

bubble.pde

int screen_height      = 1920;
int screen_width       = 1080; 
int image_width        = 1080;
int image_height       = 1350;
int top_bottom         = (screen_height - image_height) / 2;
int top_bottom_border  = 30;

int local_test         = 1;
int local_div          = 3;

String[] filenames;

void setup() {
  
  if (local_test == 1) {
    screen_height      = screen_height / local_div;
    screen_width       = screen_width / local_div; 
    image_width        = image_width / local_div;
    image_height       = image_height / local_div;
    top_bottom         = (screen_height - image_height) / 2;
    top_bottom_border  = top_bottom_border / local_div;
  }
  
  noCursor();
  
  fullScreen(SPAN);
  //fullScreen(1);  // for single screen span
  
  background(0);
  noStroke();
  fill(102);  
  
  String path = sketchPath("images");
  filenames= listFileNames(path);
  //printArray(filenames);

  noLoop();
}

String getRandomImage() {
  int index = int(random(filenames.length)); 
  String img_string = "images/"+filenames[index];  
  return img_string;
}

void mousePressed() {
  redraw();
}
void draw() {
  PImage img1 = loadImage(getRandomImage());
  PImage img2 = loadImage(getRandomImage());
  PImage img3 = loadImage(getRandomImage());
  PImage img4 = loadImage(getRandomImage());
  PImage img5 = loadImage(getRandomImage());
  PImage img6 = loadImage(getRandomImage());
  PImage img7 = loadImage(getRandomImage());
  PImage img8 = loadImage(getRandomImage());
  PImage img9 = loadImage(getRandomImage());
  
  img1.resize(image_width, image_height);
  image(img1, 0, top_bottom);
  
  img2.resize(image_width, image_height);
  image(img2, screen_width, top_bottom);
  
  img3.resize(image_width, image_height);
  image(img3, screen_width*2, top_bottom);
  
  // top images 

  img4.resize(image_width, image_height);
  image(img4, 0,    top_bottom - image_height - top_bottom_border);
  
  img5.resize(image_width, image_height);
  image(img5, screen_width, top_bottom - image_height -top_bottom_border);
  
  img6.resize(image_width, image_height);
  image(img6, screen_width*2, top_bottom - image_height - top_bottom_border);
  
  // top images 

  img7.resize(image_width, image_height);
  image(img7, 0,    top_bottom + image_height + top_bottom_border);
  
  img8.resize(image_width, image_height);
  image(img8, screen_width, top_bottom + image_height + top_bottom_border);
  
  img9.resize(image_width, image_height);
  image(img9, screen_width*2, top_bottom + image_height + top_bottom_border);
  
  if(local_test == 1) {
    fill(0);         
    rect(0,screen_height,screen_width*3,screen_height); 
  }
}

String[] listFileNames(String dir) {
  File file = new File(dir);
  if (file.isDirectory()) {
    String names[] = file.list();
    return names;
  } else {
    return null;
  }
}