diff --git a/Libraries/Utilities/PixelRatio.js b/Libraries/Utilities/PixelRatio.js index 0eeb074c6..f9b1ac13a 100644 --- a/Libraries/Utilities/PixelRatio.js +++ b/Libraries/Utilities/PixelRatio.js @@ -10,45 +10,49 @@ 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 + * ### 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 + * 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() }} + * ``` + * style={{ borderWidth: 1 / PixelRatio.get() }} + * ``` * - * == Fetching a correctly sized image + * ### 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() - * }); - * + * ``` + * var image = getImage({ + * width: 200 * PixelRatio.get(), + * height: 100 * PixelRatio.get() + * }); + * + * ``` */ 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; } +} - static startDetecting() { - // no-op for iOS, but this is useful for other platforms - } -}; +// No-op for iOS, but used on the web. Should not be documented. +PixelRatio.startDetecting = function() {}; module.exports = PixelRatio;