70 lines
2.2 KiB
JavaScript
70 lines
2.2 KiB
JavaScript
/**
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* Copyright (c) 2015-present, Facebook, Inc.
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* All rights reserved.
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*
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* This source code is licensed under the BSD-style license found in the
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* LICENSE file in the root directory of this source tree. An additional grant
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* of patent rights can be found in the PATENTS file in the same directory.
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*
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* @providesModule Dimensions
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* @flow
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*/
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'use strict';
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var UIManager = require('UIManager');
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var invariant = require('invariant');
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var dimensions = UIManager.Dimensions;
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// We calculate the window dimensions in JS so that we don't encounter loss of
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// precision in transferring the dimensions (which could be non-integers) over
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// the bridge.
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if (dimensions && dimensions.windowPhysicalPixels) {
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// parse/stringify => Clone hack
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dimensions = JSON.parse(JSON.stringify(dimensions));
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var windowPhysicalPixels = dimensions.windowPhysicalPixels;
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dimensions.window = {
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width: windowPhysicalPixels.width / windowPhysicalPixels.scale,
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height: windowPhysicalPixels.height / windowPhysicalPixels.scale,
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scale: windowPhysicalPixels.scale,
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fontScale: windowPhysicalPixels.fontScale,
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};
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// delete so no callers rely on this existing
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delete dimensions.windowPhysicalPixels;
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}
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class Dimensions {
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/**
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* This should only be called from native code.
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*
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* @param {object} dims Simple string-keyed object of dimensions to set
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*/
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static set(dims: {[key:string]: any}): bool {
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Object.assign(dimensions, dims);
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return true;
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}
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/**
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* Initial dimensions are set before `runApplication` is called so they should
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* be available before any other require's are run, but may be updated later.
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*
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* Note: Although dimensions are available immediately, they may change (e.g
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* due to device rotation) so any rendering logic or styles that depend on
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* these constants should try to call this function on every render, rather
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* than caching the value (for example, using inline styles rather than
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* setting a value in a `StyleSheet`).
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*
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* @param {string} dim Name of dimension as defined when calling `set`.
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* @returns {Object?} Value for the dimension.
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*/
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static get(dim: string): Object {
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invariant(dimensions[dim], 'No dimension set for key ' + dim);
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return dimensions[dim];
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}
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}
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module.exports = Dimensions;
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