Refactor print preview web ui

chrome/browser/resources/print_preview/data/margins.js

+// Copyright (c) 2012 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+cr.define('print_preview', function() {
+  'use strict';
+
+  /**
+   * Creates a Margins object that holds four margin values. The units in which
+   * the values are expressed can be any numeric value.
+   * @param {number} top The top margin.
+   * @param {number} right The right margin.
+   * @param {number} bottom The bottom margin.
+   * @param {number} left The left margin.
+   * @param {print_preview.MeasurementSystem} measurementSystem The measurement
+   *     system.
+   * @constructor
+   */
+  function Margins(top, right, bottom, left, measurementSystem) {
+    this[Margins.TOP_GROUP] = top;
+    this[Margins.RIGHT_GROUP] = right;
+    this[Margins.BOTTOM_GROUP] = bottom;
+    this[Margins.LEFT_GROUP] = left;
+    this.measurementSystem_ = measurementSystem;
+  };
+
+  /**
+   * Enumeration of margin types. Matches enum MarginType in
+   * printing/print_job_constants.h.
+   * @enum {number}
+   */
+  Margins.Type = {
+    DEFAULT: 0,
+    NO_MARGINS: 1,
+    MINIMUM: 2,
+    CUSTOM: 3
+  },
+
+  // Group name corresponding to the top margin.
+  Margins.TOP_GROUP = 'top';
+  //  Group name corresponding to the left margin.
+  Margins.LEFT_GROUP = 'left';
+  // Group name corresponding to the right margin.
+  Margins.RIGHT_GROUP = 'right';
+  // Group name corresponding to the bottom margin.
+  Margins.BOTTOM_GROUP = 'bottom';
+
+  /**
+   * Rounds |value| keeping |precision| decimal numbers. Example: 32.76643
+   * becomes 32.77.
+   * @param {number} value The number to round.
+   * @param {number} precision The desired precision.
+   * @return {number} The rounded number.
+   */
+  Margins.roundToPrecision = function(value, precision) {
+    return Math.round(value * Math.pow(10, precision)) /
+        Math.pow(10, precision);
+  };
+
+  Margins.prototype = {
+    /**
+     * Checks if |rhs| is equal to |this|.
+     * @param {Margins} rhs The Margins object to compare against.
+     * @return {boolean} true if they are equal.
+     */
+    isEqual: function(rhs) {
+      if (!rhs)
+        return false;
+      return this[Margins.TOP_GROUP] === rhs[Margins.TOP_GROUP] &&
+          this[Margins.LEFT_GROUP] === rhs[Margins.LEFT_GROUP] &&
+          this[Margins.RIGHT_GROUP] ===
+              rhs[Margins.RIGHT_GROUP] &&
+          this[Margins.BOTTOM_GROUP] ===
+              rhs[Margins.BOTTOM_GROUP];
+    },
+
+    clone: function() {
+      return new Margins(this[Margins.LEFT_GROUP],
+                         this[Margins.TOP_GROUP],
+                         this[Margins.RIGHT_GROUP],
+                         this[Margins.BOTTOM_GROUP]);
+    },
+
+    /**
+     * Helper method returning an array of the string indices used for accessing
+     * all margins.
+     * @return {array} An array of string indices.
+     * @private
+     */
+    indicesAsArray_: function() {
+      return [Margins.LEFT_GROUP, Margins.TOP_GROUP,
+          Margins.RIGHT_GROUP, Margins.BOTTOM_GROUP];
+    },
+
+    /**
+     * Rounds |this| based on the precision used when displaying the margins in
+     * the user's prefered units. This is done by converting from points to
+     * those units (mm/inches) and back to points.
+     */
+    roundToLocaleUnits: function() {
+      var indicesAsArray = this.indicesAsArray_();
+      for (var i = 0; i < indicesAsArray.length; i++) {
+        this[indicesAsArray[i]] =
+            print_preview.convertPointsToLocaleUnitsAndBack(
+                this[indicesAsArray[i]]);
+      }
+    }
+  };
+
+  // Export
+  return {
+    Margins: Margins
+  };
+});