dat.gui/src/dat/controllers/NumberController.js

/**
 * dat-gui JavaScript Controller Library
 * http://code.google.com/p/dat-gui
 *
 * Copyright 2011 Data Arts Team, Google Creative Lab
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 */

define([
    'dat/controllers/Controller',
    'dat/utils/common'
], function(Controller, common) {

  /**
   * @class Represents a given property of an object that is a number.
   *
   * @extends dat.controllers.Controller
   *
   * @param {Object} object The object to be manipulated
   * @param {string} property The name of the property to be manipulated
   * @param {Object} [params] Optional parameters
   * @param {Number} [params.min] Minimum allowed value
   * @param {Number} [params.max] Maximum allowed value
   * @param {Number} [params.step] Increment by which to change value
   *
   * @member dat.controllers
   */
  var NumberController = function(object, property, params) {

    NumberController.superclass.call(this, object, property);

    params = params || {};

    this.__min = params.min;
    this.__max = params.max;
    this.__step = params.step;

    if (common.isUndefined(this.__step)) {

      if (this.initialValue == 0) {
        this.__impliedStep = 1; // What are we, psychics?
      } else {
        // Hey Doug, check this out.
        this.__impliedStep = Math.pow(10, Math.floor(Math.log(Math.abs(this.initialValue))/Math.LN10))/10;
      }

    } else {

    	this.__impliedStep = this.__step;

    }

    this.__precision = numDecimals(this.__impliedStep);


  };

  NumberController.superclass = Controller;

  common.extend(

      NumberController.prototype,
      Controller.prototype,

      /** @lends dat.controllers.NumberController.prototype */
      {

        setValue: function(v) {

          if (this.__min !== undefined && v < this.__min) {
            v = this.__min;
          } else if (this.__max !== undefined && v > this.__max) {
            v = this.__max;
          }

          if (this.__step !== undefined && v % this.__step != 0) {
            v = Math.round(v / this.__step) * this.__step;
          }

          return NumberController.superclass.prototype.setValue.call(this, v);

        },

        /**
         * Specify a minimum value for <code>object[property]</code>.
         *
         * @param {Number} minValue The minimum value for
         * <code>object[property]</code>
         * @returns {dat.controllers.NumberController} this
         */
        min: function(v) {
          this.__min = v;
          return this;
        },

        /**
         * Specify a maximum value for <code>object[property]</code>.
         *
         * @param {Number} maxValue The maximum value for
         * <code>object[property]</code>
         * @returns {dat.controllers.NumberController} this
         */
        max: function(v) {
          this.__max = v;
          return this;
        },

        /**
         * Specify a step value that dat.controllers.NumberController
         * increments by.
         *
         * @param {Number} stepValue The step value for
         * dat.controllers.NumberController
         * @default if minimum and maximum specified increment is 1% of the
         * difference otherwise stepValue is 1
         * @returns {dat.controllers.NumberController} this
         */
        step: function(v) {
          this.__step = v;
          this.__impliedStep = v;
          this.__precision = numDecimals(v);
          return this;
        }

      }

  );

  function numDecimals(x) {
    x = x.toString();
    if (x.indexOf('.') > -1) {
      return x.length - x.indexOf('.') - 1;
    } else {
      return 0;
    }
  }

  return NumberController;

});