ratchet/types/transform.js

CSS3 Transform Parsers and Generator

const XYZ = require('./xyz');

const scaleOps = {
  add: 'mul',
  sub: 'div'
};

function RatchetTransform(opts) {
  if (!(this instanceof RatchetTransform)) {
    return new RatchetTransform(opts);
  }

  opts = opts || {};

  // ensure the scale units are set to an empty string
  opts.scale = opts.scale || {};
  opts.scale.units = '';
  opts.scale.defaultValue = 1;

  // set the rotation units
  opts.rotate = opts.rotate || {};
  opts.rotate.units = 'deg';

  // create new translation rotation and scale values,
  // duplicating the value provided
  this.translate = new XYZ('translate', opts.translate);
  this.rotate = new XYZ('rotate', opts.rotate);
  this.scale = new XYZ('scale', opts.scale);
}

module.exports = RatchetTransform;

RatchetTransform.prototype.clone = function() {
  return new RatchetTransform({
    translate: this.translate,
    scale: this.scale,
    rotate: this.rotate
  });
};

RatchetTransform.prototype.toString = function(opts) {
  var output = this.translate.toString(opts);
  var rotate = this.rotate.toString(opts);
  var scale = this.scale.toString(opts);

  if (rotate) {
    output += (output ? ' ' : '') + rotate;
  }

  if (scale) {
    output += (output ? ' ' : '') + scale;
  }

  return output;
};

['add', 'sub'].forEach(function(op) {
  RatchetTransform.prototype[op] = function() {
    // create new values to receive target values
    var newTransform = new RatchetTransform();

    // calculate the translation change
    newTransform.translate = XYZ.prototype[op].apply(
      this.translate,
      Array.prototype.map.call(arguments, function(item) {
        return item.translate;
      })
    );

    // calculate the scale change (mapping add to mul)
    newTransform.scale = XYZ.prototype[scaleOps[op]].apply(
      this.scale,
      Array.prototype.map.call(arguments, function(item) {
        return item.scale;
      })
    );

    // calculate the rotation update
    newTransform.rotate = XYZ.prototype[op].apply(
      this.rotate,
      Array.prototype.map.call(arguments, function(item) {
        return item.rotate;
      })
    );

    return newTransform;
  };
});