Function computeDiffRatio

scripts/reproWorkspaceSwitchTearWeb.ts:362–378

(leftPng: Buffer, rightPng: Buffer)

}

async function computeDiffRatio(leftPng: Buffer, rightPng: Buffer): Promise<number> {
  const [left, right] = await Promise.all([
    sharp(leftPng).ensureAlpha().raw().toBuffer({ resolveWithObject: true }),
    sharp(rightPng).ensureAlpha().raw().toBuffer({ resolveWithObject: true }),
  ]);
  if (left.info.width !== right.info.width || left.info.height !== right.info.height) return 1;
  let differentPixels = 0;
  const totalPixels = left.info.width * left.info.height;
  for (let offset = 0; offset < left.data.length; offset += 4) {
    const delta =
      Math.abs(left.data[offset] - right.data[offset]) +
      Math.abs(left.data[offset + 1] - right.data[offset + 1]) +
      Math.abs(left.data[offset + 2] - right.data[offset + 2]);
    if (delta > 30) differentPixels += 1;
  }
  return differentPixels / totalPixels;
}

async function detectVisualInstability(frames: SwitchFrameSample[]) {
  const anchorIndex = frames.findIndex((frame) => frame.containsTargetMarker);