supportsOverlayBlendMode.js

supportsOverlayBlendMode.js

const supportsOverlayBlendMode = (() => {
  const canvas = document.createElement('canvas')
  canvas.width = canvas.height = 1
  const ctx = canvas.getContext('2d')
  const bounds = [0, 0, 1, 1]

  ctx.globalCompositeOperation = 'overlay'
  ctx.fillStyle = '#000000'
  ctx.fillRect(...bounds)
  ctx.fillStyle = '#ffffff'
  ctx.fillRect(...bounds)

  const imageData = ctx.getImageData(...bounds)
  return imageData.data[0] === 0
})()