old_contents: /**
   * Copyright 2004-present Facebook. All Rights Reserved.
   *
   * @providesModule PixelRatio
   */
  'use strict';
  
  var Dimensions = require('Dimensions');
  
  /**
   * PixelRatio class gives access to the device pixel density.
   *
   * Some examples:
   *   - PixelRatio.get() === 2
   *     - iPhone 4, 4S
   *     - iPhone 5, 5c, 5s
   *     - iPhone 6
   *
   *   - PixelRatio.get() === 3
   *     - iPhone 6 plus
   *
   * There are a few use cases for using PixelRatio:
   *
   * == Displaying a line that's as thin as the device permits
   *
   * A width of 1 is actually pretty thick on an iPhone 4+, we can do one that's
   * thinner using a width of 1 / PixelRatio.get(). It's a technique that works
   * on all the devices independent of their pixel density.
   *
   *   style={{ borderWidth: 1 / PixelRatio.get() }}
   *
   * == Fetching a correctly sized image
   *
   * You should get a higher resolution image if you are on a high pixel density
   * device. A good rule of thumb is to multiply the size of the image you display
   * by the pixel ratio.
   *
   *   var image = getImage({
   *     width: 200 * PixelRatio.get(),
   *     height: 100 * PixelRatio.get()
   *   });
   *   <Image source={image} style={{width: 200, height: 100}} />
   */
  class PixelRatio {
    static get() {
      return Dimensions.get('window').scale;
    }
  
    static startDetecting() {
      // no-op for iOS, but this is useful for other platforms
    }
  };
  
  module.exports = PixelRatio;
  
new_contents: /**
   * Copyright 2004-present Facebook. All Rights Reserved.
   *
   * @providesModule PixelRatio
   */
  'use strict';
  
  var Dimensions = require('Dimensions');
  
  /**
   * PixelRatio class gives access to the device pixel density.
   *
   * There are a few use cases for using PixelRatio:
   *
   * ### Displaying a line that's as thin as the device permits
   *
   * A width of 1 is actually pretty thick on an iPhone 4+, we can do one that's
   * thinner using a width of `1 / PixelRatio.get()`. It's a technique that works
   * on all the devices independent of their pixel density.
   *
   * ```
   * style={{ borderWidth: 1 / PixelRatio.get() }}
   * ```
   *
   * ### Fetching a correctly sized image
   *
   * You should get a higher resolution image if you are on a high pixel density
   * device. A good rule of thumb is to multiply the size of the image you display
   * by the pixel ratio.
   *
   * ```
   * var image = getImage({
   *   width: 200 * PixelRatio.get(),
   *   height: 100 * PixelRatio.get()
   * });
   * <Image source={image} style={{width: 200, height: 100}} />
   * ```
   */
  class PixelRatio {
    /**
     * Returns the device pixel density. Some examples:
     *
     *   - PixelRatio.get() === 2
     *     - iPhone 4, 4S
     *     - iPhone 5, 5c, 5s
     *     - iPhone 6
     *   - PixelRatio.get() === 3
     *     - iPhone 6 plus
     */
    static get() {
      return Dimensions.get('window').scale;
    }
  }
  
  // No-op for iOS, but used on the web. Should not be documented.
  PixelRatio.startDetecting = function() {};
  
  module.exports = PixelRatio;
  
subject: Improve PixelRatio documentation