replica-diff

# replica-diff Two tools in this folder, both standard-library Python, no installs: ```bash python3 parity.py replica/features.csv # feature parity + missing list python3 imgdiff.py replica/screens/S07.png replica/clone-screens/S07.png --out diff-S07.png python3 imgdiff.py a.png b.png --json > replica/diffs/S07.json # for parity.py --visual python3 parity.py replica/features.csv --visual replica/diffs/*.json --markdown > replica/parity.md ``` ## What parity means here **Parity means it does the same job, not that it looks the same.** The feature score is the number that matters: can a user do everything they could do in the original. The layout score checks structure (is the information in the same places, in the same hierarchy), because that is what makes a switcher feel at home. It deliberately ignores colour, because replica-brand changes every colour on purpose. Do not chase pixel parity with the original. Its exact look is its trade dress, and it changes before launch. ## Step 1: feature parity Make sure `replica/features.csv` is current: every row's `clone` column is `yes`, `partial` (with a note), `no`, or `skip` (with a reason). Then: ```bash python3 parity.py replica/features.csv ``` It weights must 3, should 2, could 1, counts partial as half, leaves out `skip` rows and rows you added that the original does not have, and prints: the score, must-haves done of total, each area weakest first, and the missing list in build order. Must-haves not done means not shippable, and it says so. ## Step 2: layout diff For each key screen, take two screenshots at the **same viewport** (1440x900 desktop, 390x844 mobile) in the **same state** (same data shape, same tab open, logged in the same way). The original's come from public pages or the user's own account, saved in `replica/screens/`. The clone's go in `replica/clone-screens/`. ```bash python3 imgdiff.py replica/screens/S07.png replica/clone-screens/S07.png --out replica/diffs/S07.png ``` Layout mode (default) turns both into edge maps, cuts them into a grid, and compares where things are, scoring only cells with something in them. It reports the score (matches 90+, close 75+, partly 50+, different), the regions that differ (in the original's pixel coordinates, biggest first), and a height difference if the clone's page is much longer or shorter. Retina and non-retina screenshots compare fine: both are scaled to the same width. `--mode pixel` is exact comparison. Use it for your own regressions (clone today against clone last week), not against the original. ## Step 3: behaviour diff Walk each flow in both apps and compare what the scores cannot see: clicks to finish the core flow, what happens on errors, what is remembered between visits, what emails arrive. Fewer clicks than the original is a win. Write each difference as: flow, original does, clone does, fix or keep. ## Step 4: the report `replica/parity.md`: overall score, feature score, layout score per screen, missing features in build order, behaviour differences, and a verdict: - **not shippable**: any must-have missing, or any open S1 bug - **shippable**: all must-haves done, feature score 80+, no open S1 or S2 - **better than the original**: shippable, plus fixes from replica-entrepreneur. This is the goal. A straight copy has no reason to exist. Give honest numbers. A clone at 62% is at 62%. ## Output `replica/parity.md`, the diff images, and the top five things to build next. Then `/replica-build` for the gaps, or `/replica-entrepreneur` if parity is there.