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 {boolean} true if the |text| represents a valid margin value
+   */
+  function extractMarginValue(text) {
+    // Remove whitespace anywhere in the string.
+    text.replace(/\s*/g, '');
+    // TODO(dpapad): Return -1 instead of null to indicate an invalid value.

[Evan Stade, 2011/10/05 22:42:14]

is this todo still valid? what's wrong with what it's doing now?

[dpapad, 2011/10/06 00:05:39]

This TODO is not necessary, i just though it is better to return -1 which is
also invalid and still of type number.

+    if (text.length == 0)
+      return null;
+    // 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 text;
+    return null;
+  }
+
+  /**
+   * @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 ==  null)
+      return false;
+    value = print_preview.MarginSettings.convertInchesToPoints(value);
+    return value <= limit;
+  }
+
+  /**
+   * Creates a Rect object. This object describes a rectangle in a 2D plane.

[Evan Stade, 2011/10/05 22:42:14]

here is where you would mention that the units can be percentages of a page (or
always are percentages?)

[dpapad, 2011/10/06 00:05:39]

Done.

+   * @constructor
+   */
+  function Rect(x, y, width, height) {
+    this.x_ = x;
+    this.y_ = y;
+    this.width_ = width;
+    this.height_ = height;
+  };
+
+  Rect.prototype = {
+    get x() {

[Evan Stade, 2011/10/05 22:42:14]

remove the getters you don't need (all but origin)

[dpapad, 2011/10/06 00:05:39]

Done. Removed origin too since it is not used in the code.

+      return this.x_;
+    },
+    get y() {
+      return this.y_;
+    },
+    get origin() {
+      return this.origin_;
+    },
+    get width() {
+      return this.width_;
+    },
+    get height() {
+      return this.height_;
+    },
+  };
+
+  return {
+    extractMarginValue: extractMarginValue,
+    isMarginTextValid: isMarginTextValid,
+    Rect: Rect,
+  };
+});