hiDPI.js

// @flow

/**
 * Generates a media query to target HiDPI devices.
 *
 * @example
 * // Styles as object usage
 * const styles = {
 *  [hiDPI(1.5)]: {
 *    width: 200px;
 *  }
 * }
 *
 * // styled-components usage
 * const div = styled.div`
 *   ${hiDPI(1.5)} {
 *     width: 200px;
 *   }
 * `
 *
 * // CSS as JS Output
 *
 * '@media only screen and (-webkit-min-device-pixel-ratio: 1.5),
 *  only screen and (min--moz-device-pixel-ratio: 1.5),
 *  only screen and (-o-min-device-pixel-ratio: 1.5/1),
 *  only screen and (min-resolution: 144dpi),
 *  only screen and (min-resolution: 1.5dppx)': {
 *   'width': '200px',
 * }
 */

function hiDPI(ratio: number = 1.3) {
  return `
    @media only screen and (-webkit-min-device-pixel-ratio: ${ratio}),
    only screen and (min--moz-device-pixel-ratio: ${ratio}),
    only screen and (-o-min-device-pixel-ratio: ${ratio}/1),
    only screen and (min-resolution: ${Math.round((ratio * 96))}dpi),
    only screen and (min-resolution: ${ratio}dppx)
  `
}

export default hiDPI