replica-diff Checked

Compares an app clone against the original: a feature parity score from the feature matrix (weighted by must, should, could) with the missing list in build order, plus a screenshot layout diff that ignores colour so a rebrand does not count against you. Two standard-library Python tools. Use when the user says "how close is my clone", "compare it to the original", "what's missing", "parity check", "diff the screens", "is it ready", or after /replica-test.

replica-diff

Two tools in this folder, both standard-library Python, no installs:

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

Compares an app clone against the original: a feature parity score from the feature matrix (weighted by must, should, could) with the missing list in build order, plus a screenshot layout diff that ignores colour so a rebrand does not count against you. Two standard-library Python tools. Use when the user says "how close is my clone", "compare it to the original", "what's missing", "parity check", "diff the screens", "is it ready", or after /replica-test.

replica-diff

Two tools in this folder, both standard-library Python, no installs:

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:

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/.

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.