Broadway Boogie Woogie, 1942 by Piet Mondrian

 // By Laura Krok aka lakrok

​

var thickness = 8; // thickness of the lines between the cubes

var colors; // colors used, including black and white

var nbColors; // number of colors

var startingProbColors; // starting probabilities

var probColors; // probabilities of applying each color to a rectangle, the sum of its elements must be equal to 1.0

var probReducingColors; // gives how the probabilities for each color evolve every time we use them (the closest to 1, the more we'll reduce)

​

var probFactor = 0.9; // factor to multiply the probability of division with when we call the function mondrianRecursion recursively

​

function setup() {

  createCanvas(1240, 1748);

  noLoop();

  stroke(255, 255, 0); 

  colors = [[255, 255, 0], [255, 255, 255], [10, 10, 255], [230, 227, 207], [255, 50, 1, 0]];

  nbColors = colors.length;

  startingProbColors = [0.01, 0.81, 0.06, 0.06, 0.06];

  probColors = startingProbColors.slice();

  probReducingColors = [0.8, 0.1, 0.5, 0.5, 0.5];

}

​

function draw() {

  background(255, 255, 0);

  mondrianRecursion(width - thickness, height - thickness, thickness/2, thickness/2, 1.0, (random(2)<1));

}

​

/* Draws a generated Mondrian-style picture recursively

   w the width, h the height, (x,y) the top-left corner

   prob the probability to divide this rectangle into 2 new rectangles

   vertical = true if we must divide vertically, false if horizontally */

function mondrianRecursion(w, h, x, y, prob, vertical) {

  if (random(1) < prob) { // we must divide again

    if (vertical) {

      var wDivision=floor(random(w*0.3, w*0.7));

      mondrianRecursion(wDivision, h, x, y, prob*probFactor, false);

      mondrianRecursion(w - wDivision, h, x + wDivision, y, prob*probFactor, false);

    } else {

      var hDivision=floor(random(h*0.3, h*0.7));

      mondrianRecursion(w, hDivision, x, y, prob*probFactor, true);

      mondrianRecursion(w, h - hDivision, x, y + hDivision, prob*probFactor, true);

    }

  } else { // we must draw a rectangle in the zone

    var idx = chooseColor();

    newProbColors(idx);

    fill(colors[idx][0], colors[idx][1], colors[idx][2]);

    rect(x + thickness/2, y + thickness/2, w - thickness, h - thickness);

  }

}

​

/* Choose a color randomly using the probability distribution of probColors */

​

function chooseColor() {

  var r = random(1), sum = 0;

  var i = 0;

  while (sum <= r) {

    sum += probColors[i++];

  }  

  return i - 1;

}

​

/* Changes probColors during the execution in order not to have too much of a certain color

   Reduces the probability of the last used color and redistributes it uniformly to all the others */

​

function newProbColors(i) {

  var x = probColors[i] * probReducingColors[i];

  for (var k = 0; k < nbColors; k++) {

    if (i === k) {

      probColors[k] = probColors[k] - x; // decrease this probability

    } else {

      probColors[k] = probColors[k] + x / (nbColors-1); // increase all the other ones

    }

  }

}

​

function keyTyped() {

  if (key === "s" || key === "S") {

    noLoop();

    saveCanvas("MondrianBroadwayBoogieWoogie1240x1748", "jpeg");

  }

}