{"abstract":"Layer opacity reduces alpha while leaving premultiplied color unchanged.","category":"Raster compositing","checks":4,"contract":"Apply normalized layer opacity to premultiplied RGBA by scaling both RGB and alpha.","contract_signature":"rgba, opacity","evaluation_group":"xg-global-opacity-premultiplied","failed_approach":"Scaling color alone leaves the old destination occlusion intact.","family":"xg-global-opacity-premultiplied","id":"FA-10556","implementations":{"attempt":{"sha256":"b1509bf42b863b925dd7bb5a5f6e7cfb0e88023f50ce1d766a69eb6d6d539119","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\nimport math\nN = 1\nobservations = []\ndef solve(rgba, opacity):\n    return [x*opacity for x in rgba[:3]]+[rgba[3]]\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('fixture 1', solve(*([0.5, 0.25, 0, 0.5], 0.5)), [0.25, 0.125, 0, 0.25])\ncheck('fixture 2', solve(*([1, 1, 1, 1], 0)), [0, 0, 0, 0])\ncheck('fixture 3', solve(*([0.25, 0, 0, 0.5], 1)), [0.25, 0, 0, 0.5])\ncheck('fixture 4', solve(*([0, 0, 0, 0], 0.5)), [0, 0, 0, 0])\nprint(json.dumps({\"observations\": observations, \"passed\": all(x[\"passed\"] for x in observations)}, ensure_ascii=False))\nraise SystemExit(0 if all(x[\"passed\"] for x in observations) else 1)\n"},"broken":{"sha256":"a399c0c4fa2a32009de51c242d2824197f0a7d2d6a6baca142c9b20497390538","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\nimport math\nN = 1\nobservations = []\ndef solve(rgba, opacity):\n    return rgba[:3]+[rgba[3]*opacity]\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('fixture 1', solve(*([0.5, 0.25, 0, 0.5], 0.5)), [0.25, 0.125, 0, 0.25])\ncheck('fixture 2', solve(*([1, 1, 1, 1], 0)), [0, 0, 0, 0])\ncheck('fixture 3', solve(*([0.25, 0, 0, 0.5], 1)), [0.25, 0, 0, 0.5])\ncheck('fixture 4', solve(*([0, 0, 0, 0], 0.5)), [0, 0, 0, 0])\nprint(json.dumps({\"observations\": observations, \"passed\": all(x[\"passed\"] for x in observations)}, ensure_ascii=False))\nraise SystemExit(0 if all(x[\"passed\"] for x in observations) else 1)\n"}},"limitations":" 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.","method":"Deterministic executable model with adversarial boundary fixtures.","provenance":{"created_by":"Failure Map","dependencies":"Python standard library","family":"xg-global-opacity-premultiplied","generated_at":"2026-09-29T14:38:40.029078+00:00","license":"CC0-1.0","python":"3.12.14","seed":1,"split":"open-access"},"relevance":"A deterministic software graphics stage with explicit channel and coordinate conventions; no hardware, device profile or API behavior is inferred.","root_cause":"Layer opacity reduces alpha while leaving premultiplied color unchanged.","sha256":"0feedc8eba7a6e559fe731cb93678e6384f4e94bacd48994417d924334dbb615","title":"Global opacity premultiplied · case 01","variant":1,"variant_policy":"Five numbered records share a model and may reuse boundary fixtures.","verified":true,"visibility":"public","verification":{"attempt":{"elapsed_ms":41.7,"exit_code":1,"observations":[{"actual":[0.25,0.125,0.0,0.5],"check":"fixture 1","expected":[0.25,0.125,0,0.25],"passed":false},{"actual":[0,0,0,1],"check":"fixture 2","expected":[0,0,0,0],"passed":false},{"actual":[0.25,0,0,0.5],"check":"fixture 3","expected":[0.25,0,0,0.5],"passed":true},{"actual":[0.0,0.0,0.0,0],"check":"fixture 4","expected":[0,0,0,0],"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"fixture 1\", \"actual\": [0.25, 0.125, 0.0, 0.5], \"expected\": [0.25, 0.125, 0, 0.25], \"passed\": false}, {\"check\": \"fixture 2\", \"actual\": [0, 0, 0, 1], \"expected\": [0, 0, 0, 0], \"passed\": false}, {\"check\": \"fixture 3\", \"actual\": [0.25, 0, 0, 0.5], \"expected\": [0.25, 0, 0, 0.5], \"passed\": true}, {\"check\": \"fixture 4\", \"actual\": [0.0, 0.0, 0.0, 0], \"expected\": [0, 0, 0, 0], \"passed\": true}], \"passed\": false}\n"},"broken":{"elapsed_ms":40.191,"exit_code":1,"observations":[{"actual":[0.5,0.25,0,0.25],"check":"fixture 1","expected":[0.25,0.125,0,0.25],"passed":false},{"actual":[1,1,1,0],"check":"fixture 2","expected":[0,0,0,0],"passed":false},{"actual":[0.25,0,0,0.5],"check":"fixture 3","expected":[0.25,0,0,0.5],"passed":true},{"actual":[0,0,0,0.0],"check":"fixture 4","expected":[0,0,0,0],"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"fixture 1\", \"actual\": [0.5, 0.25, 0, 0.25], \"expected\": [0.25, 0.125, 0, 0.25], \"passed\": false}, {\"check\": \"fixture 2\", \"actual\": [1, 1, 1, 0], \"expected\": [0, 0, 0, 0], \"passed\": false}, {\"check\": \"fixture 3\", \"actual\": [0.25, 0, 0, 0.5], \"expected\": [0.25, 0, 0, 0.5], \"passed\": true}, {\"check\": \"fixture 4\", \"actual\": [0, 0, 0, 0.0], \"expected\": [0, 0, 0, 0], \"passed\": true}], \"passed\": false}\n"}},"member_only":{"stages":["fixed"],"fields":["implementations.fixed","verification.fixed","harness","repair"],"note":"The verified repair, its recorded checks, the repair description, and the scoring harness are available to members."}}