// note that this ONLY works with ttf fonts, which provide

// the shapes of counters (i.e., the hole in 'O') in

// counter-clockwise order. I use this in the code below

// with the beginContour()/endContour() functions in p5js

// to draw the shapes accordingly.

​

let font;

let fontData;

​

// groups a list of opentype.js vector commands by contour

function groupByContour(cmds) {

  contours = [];

  current = [];

  for (let cmd of cmds) {

    current.push(cmd);

    if (cmd.type == 'Z') {

      contours.push(current);

      current = [];

    }

  }

  return contours;

}

​

// determines if a list of commands specify a path in clockwise

// or counter-clockwise order

function clockwise(cmds) {

  let sum = 0;

  for (let i = 0; i < cmds.length - 1; i++) {

    let a = cmds[i];

    let b = cmds[i+1];

    if (!(a.hasOwnProperty('x') && b.hasOwnProperty('x'))) {

      continue;

    }

    sum += (b.x - a.x) * (b.y + a.y);

  }

  return sum < 0;

}

​

// draws contours grouped by groupByContour(). uses clockwise()

// to determine if this contour should be a p5js shape or a p5js

// contour (i.e., cutout of a shape)

function drawContours(contours) {

  let inShape = false;

  for (let i = 0; i < contours.length; i++) {

    if (clockwise(contours[i])) {

      if (inShape) {

        endShape(CLOSE);

      }

      beginShape();

      inShape = true;

      drawContour(contours[i]);

    }

    else {

      beginContour();

      drawContour(contours[i]);

      endContour();

    }

  }

  if (inShape) {

    endShape(CLOSE);

  }

}

​

// draws an individual contour

function drawContour(cmds) {

  for (let i = 0; i < cmds.length; i++) {

    cmd = cmds[i];

    switch (cmd.type) {

      case 'M':

      case 'Z':

        break;

      case 'L':

        vertex(cmd.x, cmd.y);

        break;

      case 'C':

        bezierVertex(

          cmd.x1, cmd.y1, cmd.x2, cmd.y2, cmd.x, cmd.y);

        break;

      case 'Q':

        quadraticVertex(cmd.x1, cmd.y1, cmd.x, cmd.y);

        break;

        }    

  }

}

​

function preload() {

  fontData = loadBytes('ReplicaProTT-Bold.ttf');

}

​

let path;

​

function setup() {

    createCanvas(400, 400);

  font = opentype.parse(fontData.bytes.buffer);

  path = font.getPath("Design", 0, 0, 72);

}

​

// applies a transformation to the x/y coordinates of each opentypejs

// command you pass to it, according to the callback, which will be

// given the x/y coordinates as parameters and should return an array

// in the form of [x, y]

function commandTransform(cmds, callback) {

  let transformed = [];

    for (let cmd of cmds) {

    let newCmd = {type: cmd.type}

    for (let pair of [['x', 'y'], ['x1', 'y1'], ['x2', 'y2']]) {

      if (cmd.hasOwnProperty(pair[0]) && cmd.hasOwnProperty(pair[1])) {

        let result = callback(cmd[pair[0]], cmd[pair[1]]);

        newCmd[pair[0]] = result[0];

        newCmd[pair[1]] = result[1];

      }

    }

    transformed.push(newCmd);

  }

  return transformed;

}

​

function draw() {

  background(255);

  fill(40);

  noStroke;

  push();

  translate(25, 150);

  drawContours(

    groupByContour(

      commandTransform(path.commands, function(x, y) {

        let newX = x + sin((x*0.15) + (frameCount*0.11));

        let newY = y + cos((y*0.35) + (frameCount*0.17));

        return [newX, newY];

      })

    )

  );

  pop();

}