Safe Area / Title-Safe Overlay Calculator implementation

Binding contract

This record describes what an executable surface must bind and validate. It does not claim that a public calculator, package, or production route is deployed.

Record owner

Guth Instruments

Lifecycle

verified-clean

Evidence ID

t4-296

Effect

Computation or source lookup only

Input and validation requirements

The specification does not define validation for percentages outside 0-100, integer-resolution requirements, floating-point limits, or inclusive versus half-open pixel endpoints. A title percentage above 100% therefore produces an out-of-frame rectangle unless rejected, and extreme dimensions cause subpixel margin collapse and potentially inconsistent floating-point results.

Required corrections

No binding erratum is attached to this unique-name record. Implementers must still preserve the declared units, domain, and failure behavior.

Inspectable interface fixture

The sample below is evidence for interface and validation tests, not a production implementation.

{
  "inputs": {
    "resolution": {
      "width_px": 1920,
      "height_px": 1080
    },
    "safe_area_percentages": {
      "action": 90,
      "title": 80
    }
  },
  "expected_outputs": {
    "action_safe": {
      "left": 96,
      "top": 54,
      "right": 1824,
      "bottom": 1026
    },
    "title_safe": {
      "left": 192,
      "top": 108,
      "right": 1728,
      "bottom": 972
    }
  },
  "working": "Action width = 1920 × 0.90 = 1728; action height = 1080 × 0.90 = 972; horizontal margin = (1920 − 1728) ÷ 2 = 96; vertical margin = (1080 − 972) ÷ 2 = 54; action rectangle = (96, 54) to (96 + 1728, 54 + 972) = (96, 54) to (1824, 1026). Title width = 1920 × 0.80 = 1536; title height = 1080 × 0.80 = 864; horizontal margin = (1920 − 1536) ÷ 2 = 192; vertical margin = (1080 − 864) ÷ 2 = 108; title rectangle = (192, 108) to (192 + 1536, 108 + 864) = (192, 108) to (1728, 972)."
}

Other records

Sources and evidence

These pointers bind the page to evidence. They do not grant authority or collapse verification into deployment.

• VERIFIED_LEDGER.json
• evidence-tranche4/tranche4-results.json