create-expo-cljs-app
Version:
Create a react native application with Expo and Shadow-CLJS!
50 lines (44 loc) • 1.31 kB
JavaScript
/**
* Copyright (c) Nicolas Gallagher.
* Copyright (c) Facebook, Inc. and its affiliates.
*
* This source code is licensed under the MIT license found in the
* LICENSE file in the root directory of this source tree.
*
* @flow
*/
import Dimensions from '../Dimensions';
/**
* PixelRatio gives access to the device pixel density.
*/
export default class PixelRatio {
/**
* Returns the device pixel density.
*/
static get(): number {
return Dimensions.get('window').scale;
}
/**
* No equivalent for Web
*/
static getFontScale(): number {
return Dimensions.get('window').fontScale || PixelRatio.get();
}
/**
* Converts a layout size (dp) to pixel size (px).
* Guaranteed to return an integer number.
*/
static getPixelSizeForLayoutSize(layoutSize: number): number {
return Math.round(layoutSize * PixelRatio.get());
}
/**
* Rounds a layout size (dp) to the nearest layout size that corresponds to
* an integer number of pixels. For example, on a device with a PixelRatio
* of 3, `PixelRatio.roundToNearestPixel(8.4) = 8.33`, which corresponds to
* exactly (8.33 * 3) = 25 pixels.
*/
static roundToNearestPixel(layoutSize: number): number {
const ratio = PixelRatio.get();
return Math.round(layoutSize * ratio) / ratio;
}
}