{
  "context": "This criteria evaluates how well the engineer uses pixelmatch to implement dual-mode comparison functionality, specifically focusing on the ability to call the library with and without diff output generation, and properly handling the output buffer parameter.",
  "type": "weighted_checklist",
  "checklist": [
    {
      "name": "Import pixelmatch",
      "description": "Code imports the pixelmatch function from the pixelmatch package using require() or import statement.",
      "max_score": 10
    },
    {
      "name": "Conditional buffer allocation",
      "description": "Code allocates a diff output buffer (using Uint8Array or Buffer) of size width * height * 4 only when generateDiff is true, and passes null when generateDiff is false.",
      "max_score": 25
    },
    {
      "name": "Call pixelmatch correctly",
      "description": "Code calls pixelmatch() with correct parameters: img1, img2, output buffer (or null), width, height, and passes any additional options as needed.",
      "max_score": 25
    },
    {
      "name": "Capture mismatch count",
      "description": "Code captures and returns the numeric return value from pixelmatch() as the mismatchCount, understanding that pixelmatch returns the number of mismatched pixels.",
      "max_score": 20
    },
    {
      "name": "Return correct structure",
      "description": "Code returns an object with both mismatchCount (number) and diffBuffer (Buffer/Uint8Array or null) properties, matching the expected output format.",
      "max_score": 15
    },
    {
      "name": "Performance optimization awareness",
      "description": "Implementation demonstrates understanding that passing null as the output buffer to pixelmatch improves performance by skipping diff generation when not needed.",
      "max_score": 5
    }
  ]
}