// check_webp_feature:
//   'feature' can be one of 'lossy', 'lossless', 'alpha' or 'animation'.
//   'callback(feature, isSupported)' will be passed back the detection result (in an asynchronous way!)
export function checkWebpFeature (feature: string, callback: (feature: string, isSupported: boolean) => void) {
  const kTestImages: any = {
    lossy: 'UklGRiIAAABXRUJQVlA4IBYAAAAwAQCdASoBAAEADsD+JaQAA3AAAAAA',
    lossless: 'UklGRhoAAABXRUJQVlA4TA0AAAAvAAAAEAcQERGIiP4HAA==',
    alpha: 'UklGRkoAAABXRUJQVlA4WAoAAAAQAAAAAAAAAAAAQUxQSAwAAAARBxAR/Q9ERP8DAABWUDggGAAAABQBAJ0BKgEAAQAAAP4AAA3AAP7mtQAAAA==',
    animation: 'UklGRlIAAABXRUJQVlA4WAoAAAASAAAAAAAAAAAAQU5JTQYAAAD/////AABBTk1GJgAAAAAAAAAAAAAAAAAAAGQAAABWUDhMDQAAAC8AAAAQBxAREYiI/gcA',
  }
  const img = new Image()
  img.onload = function () {
    const result = (img.width > 0) && (img.height > 0)
    callback(feature, result)
  }
  img.onerror = function () {
    callback(feature, false)
  }
  img.src = 'data:image/webp;base64,' + kTestImages[feature]
}
