fabric.js/src/mixins/object_stacking.mixin.js

fabric.util.object.extend(fabric.Object.prototype, /** @lends fabric.Object.prototype */ {

  /**
   * Moves an object to the bottom of the stack of drawn objects
   * @return {fabric.Object} thisArg
   * @chainable
   */
  sendToBack: function() {
    if (this.group) {
      fabric.StaticCanvas.prototype.sendToBack.call(this.group, this);
    }
    else {
      this.canvas.sendToBack(this);
    }
    return this;
  },

  /**
   * Moves an object to the top of the stack of drawn objects
   * @return {fabric.Object} thisArg
   * @chainable
   */
  bringToFront: function() {
    if (this.group) {
      fabric.StaticCanvas.prototype.bringToFront.call(this.group, this);
    }
    else {
      this.canvas.bringToFront(this);
    }
    return this;
  },

  /**
   * Moves an object down in stack of drawn objects
   * @param {Boolean} [intersecting] If `true`, send object behind next lower intersecting object
   * @return {fabric.Object} thisArg
   * @chainable
   */
  sendBackwards: function(intersecting) {
    if (this.group) {
      fabric.StaticCanvas.prototype.sendBackwards.call(this.group, this, intersecting);
    }
    else {
      this.canvas.sendBackwards(this, intersecting);
    }
    return this;
  },

  /**
   * Moves an object up in stack of drawn objects
   * @param {Boolean} [intersecting] If `true`, send object in front of next upper intersecting object
   * @return {fabric.Object} thisArg
   * @chainable
   */
  bringForward: function(intersecting) {
    if (this.group) {
      fabric.StaticCanvas.prototype.bringForward.call(this.group, this, intersecting);
    }
    else {
      this.canvas.bringForward(this, intersecting);
    }
    return this;
  },

  /**
   * Moves an object to specified level in stack of drawn objects
   * @param {Number} index New position of object
   * @return {fabric.Object} thisArg
   * @chainable
   */
  moveTo: function(index) {
    if (this.group) {
      fabric.StaticCanvas.prototype.moveTo.call(this.group, this, index);
    }
    else {
      this.canvas.moveTo(this, index);
    }
    return this;
  }
});