Print Preview: Adding UI for margin settings.

chrome/browser/resources/print_preview/margin_utils.js

+// Copyright (c) 2011 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';
+
+  /**
+   * Checks if |text| has a valid margin value format. A valid format is
+   * parsable as a number and is greater than zero.
+   * Example: "1.00", "1", ".5", "1.1" are valid values.
+   * Example: "1.4dsf", "-1" are invalid.
+   * Note: The inch symbol (") at the end of |text| is allowed.
+   *
+   * @param {string} text The text to check.
+   * @return {number} The margin value represented by |text| or null if |text|
+   *     does not represent a valid number.
+   */
+  function extractMarginValue(text) {
+    // Remove whitespace anywhere in the string.
+    text.replace(/\s*/g, '');
+    if (text.length == 0)
+      return -1;
+    // Remove the inch(") symbol at end of string if present.
+    if (text.charAt(text.length - 1) == '\"')
+      text = text.slice(0, text.length - 1);
+    var regex = /^\d*(\.\d+)?$/
+    if (regex.test(text))
+      return parseFloat(text);
+    return -1;
+  }
+
+  /**
+   * @param {sting} text The text to check (in inches).
+   * @param {number} limit The upper bound of the valid margin range (in
+   *     points).
+   * @return {boolean} True of |text| can be parsed and it is within the allowed
+   *     range.
+   */
+  function isMarginTextValid(text, limit) {
+    var value = extractMarginValue(text);
+    if (value ==  -1)
+      return false;
+    value = convertInchesToPoints(value);
+    return value <= limit;
+  }
+
+  /**
+   * Creates a Rect object. This object describes a rectangle in a 2D plane. The
+   * units of |x|, |y|, |width|, |height| are chosen by clients of this class.
+   * @constructor
+   */
+  function Rect(x, y, width, height) {
+    // @type {number} Horizontal distance of the upper left corner from origin.
+    this.x = x;
+    // @type {number} Vertical distance of the upper left corner from origin.
+    this.y = y;
+    // @type {number} Width of |this| rectangle.
+    this.width = width;
+    // @type {number} Height of |this| rectangle.
+    this.height = height;
+  };
+
+  Rect.prototype = {
+    get right() {
+      return this.x + this.width;
+    },
+
+    get bottom() {
+      return this.y + this.height;
+    },
+
+    get middleX() {
+      return this.x + this.width / 2;
+    },
+
+    get middleY() {
+      return this.y + this.height / 2;
+    }
+  };
+
+  return {
+    extractMarginValue: extractMarginValue,
+    isMarginTextValid: isMarginTextValid,
+    Rect: Rect,
+  };
+});