@wdio/image-comparison-core@2.1.0

Minor Changes

• b194642: fix: ignore* option parity with resemble (pixelmatch)

  After v10 switched to pixelmatch, the public ignore* API did not fully match resemble.js preset behaviour. Combined modes such as ignoreLess with the default ignoreAntialiasing: true still inherited AA forgiveness, and ignoreColors used BT.601 grayscale instead of resemble brightness-only comparison.

  This release also adds compareOptions.pixelmatch so you can pass pixelmatch settings directly instead of using ignore* presets.

  What changed

  • Multiple ignore* flags now follow resemble last-wins ordering (ignoreAlpha → ignoreAntialiasing → ignoreColors → ignoreLess → ignoreNothing) instead of composing independently
  • ignoreLess, ignoreAlpha, ignoreColors, and ignoreNothing now apply their own threshold and AA rules when active; they no longer inherit default ignoreAntialiasing: true forgiveness
  • ignoreColors now compares brightness only using resemble luma weights (0.3/0.59/0.11), matching resemble v9 behaviour
  • WDIO logs a warning when multiple ignore* flags are enabled, naming which preset wins
  • New compareOptions.pixelmatch object for direct pixelmatch control (threshold, includeAA, diffColor, aaColor, diffColorAlt, alpha, diffMask, checkerboard)

  Preset reference

  Active preset	threshold	AA forgiven
  ignoreNothing	0	no
  ignoreLess	~16/255	no
  ignoreColors	~16/255	no (brightness only)
  ignoreAlpha	~16/255	no
  ignoreAntialiasing (default)	~32/255	yes

  Using compareOptions.pixelmatch

  Set it in your service config or on a single check* call. Do not put ignore* keys and pixelmatch on the same options object; that throws, even when an ignore* flag is false. Service config and method options are separate objects, so a method call can override the service compare mode for that check (a warning is logged when the mode switches).

  Service config:

  // wdio.conf.js
  services: [
    [
      "visual",
      {
        compareOptions: {
          pixelmatch: {
            threshold: 0.063,
            includeAA: true,
          },
        },
      },
    ],
  ];

  Method override when the service uses ignore* presets:

  await browser.checkScreen("homepage", {
    pixelmatch: { threshold: 0.05 },
  });

  Method override when the service uses pixelmatch:

  await browser.checkScreen("homepage", {
    ignoreLess: true,
  });

  Invalid (throws):

  compareOptions: {
    ignoreLess: false,
    pixelmatch: { threshold: 0.063 },
  }

  See pixelmatch for option details.

  What you need to do

  • No change needed if you use a single ignore* flag or rely on defaults (ignoreAntialiasing: true)
  • Set ignoreAntialiasing: false when anti-aliased pixels should count as differences
  • If you combine multiple ignore* flags, review your tests; last-wins ordering now matches resemble v9
  • If you use ignoreColors, results may differ slightly from early v10 but align with resemble v9
  • To tune pixelmatch directly, add compareOptions.pixelmatch in your service config or pass pixelmatch on individual check* calls