1// Copyright 2013 The Chromium Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style license that can be
3// found in the LICENSE file.
4
5
6/**
7 * @fileoverview Helpers for validating parameters to chrome-search:// iframes.
8 */
9
10
11/**
12 * Converts an RGB color number to a hex color string if valid.
13 * @param {number} color A 6-digit hex RGB color code as a number.
14 * @return {?string} A CSS representation of the color or null if invalid.
15 */
16function convertToHexColor(color) {
17  // Color must be a number, finite, with no fractional part, in the correct
18  // range for an RGB hex color.
19  if (isFinite(color) && Math.floor(color) == color &&
20      color >= 0 && color <= 0xffffff) {
21    var hexColor = color.toString(16);
22    // Pads with initial zeros and # (e.g. for 'ff' yields '#0000ff').
23    return '#000000'.substr(0, 7 - hexColor.length) + hexColor;
24  }
25  return null;
26}
27
28
29/**
30 * Validates a RGBA color component. It must be a number between 0 and 255.
31 * @param {number} component An RGBA component.
32 * @return {boolean} True if the component is valid.
33 */
34function isValidRBGAComponent(component) {
35  return isFinite(component) && component >= 0 && component <= 255;
36}
37
38
39/**
40 * Converts an Array of color components into RGBA format "rgba(R,G,B,A)".
41 * @param {Array.<number>} rgbaColor Array of rgba color components.
42 * @return {?string} CSS color in RGBA format or null if invalid.
43 */
44function convertArrayToRGBAColor(rgbaColor) {
45  // Array must contain 4 valid components.
46  if (rgbaColor instanceof Array && rgbaColor.length === 4 &&
47      isValidRBGAComponent(rgbaColor[0]) &&
48      isValidRBGAComponent(rgbaColor[1]) &&
49      isValidRBGAComponent(rgbaColor[2]) &&
50      isValidRBGAComponent(rgbaColor[3])) {
51    return 'rgba(' +
52            rgbaColor[0] + ',' +
53            rgbaColor[1] + ',' +
54            rgbaColor[2] + ',' +
55            rgbaColor[3] / 255 + ')';
56  }
57  return null;
58}
59