Source: tiny/core/display/TransformBase.js

import { Matrix } from '../math';

/**
 * Generic class to deal with traditional 2D matrix transforms
 *
 * @class
 * @memberof Tiny
 */
export default class TransformBase {
  /**
   *
   */
  constructor() {
    /**
     * The global matrix transform. It can be swapped temporarily by some functions like getLocalBounds()
     *
     * @member {Tiny.Matrix}
     */
    this.worldTransform = new Matrix();

    /**
     * The local matrix transform
     *
     * @member {Tiny.Matrix}
     */
    this.localTransform = new Matrix();

    this._worldID = 0;
    this._parentID = 0;
  }

  /**
   * TransformBase does not have decomposition, so this function wont do anything
   */
  updateLocalTransform() {
    // empty
  }

  /**
   * Updates the values of the object and applies the parent's transform.
   *
   * @param {Tiny.TransformBase} parentTransform - The transform of the parent of this object
   */
  updateTransform(parentTransform) {
    const pt = parentTransform.worldTransform;
    const wt = this.worldTransform;
    const lt = this.localTransform;

    // concat the parent matrix with the objects transform.
    wt.a = (lt.a * pt.a) + (lt.b * pt.c);
    wt.b = (lt.a * pt.b) + (lt.b * pt.d);
    wt.c = (lt.c * pt.a) + (lt.d * pt.c);
    wt.d = (lt.c * pt.b) + (lt.d * pt.d);
    wt.tx = (lt.tx * pt.a) + (lt.ty * pt.c) + pt.tx;
    wt.ty = (lt.tx * pt.b) + (lt.ty * pt.d) + pt.ty;

    this._worldID++;
  }
}

/**
 * Updates the values of the object and applies the parent's transform.
 *
 * @param parentTransform {Tiny.Transform} The transform of the parent of this object
 *
 */
TransformBase.prototype.updateWorldTransform = TransformBase.prototype.updateTransform;

TransformBase.IDENTITY = new TransformBase();