FA-10636 / Color encoding / Open access

Color key before opacity · case 01

Color-key transparency is ignored during RGBA conversion.

Verified by executionVariant 1 · 4 checks per implementationDownload source bundle ↓JSON ↗

ROOT CAUSE

Color-key transparency is ignored during RGBA conversion.

VERIFIED REPAIR

Use the stage contract: For straight RGB bytes, matching all three color-key channels sets alpha to zero; other pixels retain supplied alpha.

Unsuccessful approach: Matching any component makes unrelated colors transparent.

Case contract

For straight RGB bytes, matching all three color-key channels sets alpha to zero; other pixels retain supplied alpha.

Why this case matters

A deterministic software graphics stage with explicit channel and coordinate conventions; no hardware, device profile or API behavior is inferred.

1 / The failure

Exit 1

"""Failure Map reference implementation. Python standard library only."""
import json
import math
N = 1
observations = []
def solve(rgb, key, alpha):
    return list(rgb)+[alpha]
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('fixture 1', solve(*([1, 2, 3], [1, 2, 3], 255)), [1, 2, 3, 0])
check('fixture 2', solve(*([1, 2, 4], [1, 2, 3], 128)), [1, 2, 4, 128])
check('fixture 3', solve(*([0, 0, 0], [1, 2, 3], 0)), [0, 0, 0, 0])
check('fixture 4', solve(*([9, 8, 7], [1, 2, 3], 255)), [9, 8, 7, 255])
print(json.dumps({"observations": observations, "passed": all(x["passed"] for x in observations)}, ensure_ascii=False))
raise SystemExit(0 if all(x["passed"] for x in observations) else 1)

Boundary fixture	Actual	Expected	Outcome
fixture 1	`[1, 2, 3, 255]`	`[1, 2, 3, 0]`	Failed
fixture 2	`[1, 2, 4, 128]`	`[1, 2, 4, 128]`	Passed
fixture 3	`[0, 0, 0, 0]`	`[0, 0, 0, 0]`	Passed
fixture 4	`[9, 8, 7, 255]`	`[9, 8, 7, 255]`	Passed

SHA-256 / 76cc8665a03a7b4ed6ad3c4f10703b83157fc5bffdaadc3c8ae76a7195dfaa47

2 / The unsuccessful fix

Exit 1

"""Failure Map reference implementation. Python standard library only."""
import json
import math
N = 1
observations = []
def solve(rgb, key, alpha):
    return list(rgb)+[0 if any(a==b for a,b in zip(rgb,key)) else alpha]
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('fixture 1', solve(*([1, 2, 3], [1, 2, 3], 255)), [1, 2, 3, 0])
check('fixture 2', solve(*([1, 2, 4], [1, 2, 3], 128)), [1, 2, 4, 128])
check('fixture 3', solve(*([0, 0, 0], [1, 2, 3], 0)), [0, 0, 0, 0])
check('fixture 4', solve(*([9, 8, 7], [1, 2, 3], 255)), [9, 8, 7, 255])
print(json.dumps({"observations": observations, "passed": all(x["passed"] for x in observations)}, ensure_ascii=False))
raise SystemExit(0 if all(x["passed"] for x in observations) else 1)

Boundary fixture	Actual	Expected	Outcome
fixture 1	`[1, 2, 3, 0]`	`[1, 2, 3, 0]`	Passed
fixture 2	`[1, 2, 4, 0]`	`[1, 2, 4, 128]`	Failed
fixture 3	`[0, 0, 0, 0]`	`[0, 0, 0, 0]`	Passed
fixture 4	`[9, 8, 7, 255]`	`[9, 8, 7, 255]`	Passed

SHA-256 / df04f2c4fc8f0dfa3d65b0dfdf5290fcfcdaed7ce0013101915de6dc84e147e9

3 / The verified repair

Exit 0

"""Failure Map reference implementation. Python standard library only."""
import json
import math
N = 1
observations = []
def solve(rgb, key, alpha):
    return list(rgb)+[0 if list(rgb)==list(key) else alpha]
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('fixture 1', solve(*([1, 2, 3], [1, 2, 3], 255)), [1, 2, 3, 0])
check('fixture 2', solve(*([1, 2, 4], [1, 2, 3], 128)), [1, 2, 4, 128])
check('fixture 3', solve(*([0, 0, 0], [1, 2, 3], 0)), [0, 0, 0, 0])
check('fixture 4', solve(*([9, 8, 7], [1, 2, 3], 255)), [9, 8, 7, 255])
print(json.dumps({"observations": observations, "passed": all(x["passed"] for x in observations)}, ensure_ascii=False))
raise SystemExit(0 if all(x["passed"] for x in observations) else 1)

Boundary fixture	Actual	Expected	Outcome
fixture 1	`[1, 2, 3, 0]`	`[1, 2, 3, 0]`	Passed
fixture 2	`[1, 2, 4, 128]`	`[1, 2, 4, 128]`	Passed
fixture 3	`[0, 0, 0, 0]`	`[0, 0, 0, 0]`	Passed
fixture 4	`[9, 8, 7, 255]`	`[9, 8, 7, 255]`	Passed

SHA-256 / fd6657b4f708fc1af41301fbd39dd3733baeba758ee7870383f2b89e6cdd3791

Verification & scope

This reproducer isolates one failure mechanism. Results cover the supplied fixtures. Variants within a family share a test contract and should remain grouped when constructing evaluation splits. Related mechanisms with a shared evaluation_group must also remain together; these controlled models are not independent production incidents.

Observations recorded using Python 3.12.14 at 2026-09-29T14:38:40.800379+00:00.

Case digest / 5d45bde40e39543029c7f90ecba431e45828f61d3b65cc345bd209a3e74189db