react-native/Libraries/StyleSheet/setNormalizedColorAlpha.js

32 lines
851 B
JavaScript

/**
* Copyright (c) 2015-present, Facebook, Inc.
* All rights reserved.
*
* This source code is licensed under the BSD-style license found in the
* LICENSE file in the root directory of this source tree. An additional grant
* of patent rights can be found in the PATENTS file in the same directory.
*
* @providesModule setNormalizedColorAlpha
* @flow
*/
/* eslint no-bitwise: 0 */
'use strict';
/**
* number should be a color processed by `normalizeColor`
* alpha should be number between 0 and 1
*/
function setNormalizedColorAlpha(input: number, alpha: number): number {
if (alpha < 0) {
alpha = 0;
} else if (alpha > 1) {
alpha = 1;
}
alpha = Math.round(alpha * 255);
// magic bitshift guarantees we return an unsigned int
return ((input & 0xffffff00) | alpha) >>> 0;
}
module.exports = setNormalizedColorAlpha;