Aspect Ratio / Crop 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

t5-001

Effect

Computation or source lookup only

Input and validation requirements

Zero source dimensions make the scale formula undefined, but a naive plain-JavaScript implementation could propagate Infinity or invalid fitted dimensions instead of rejecting the input. The specification does not state explicit validation behavior for zero or negative resolutions.

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": {
    "sourceW": 1920,
    "sourceH": 1080,
    "targetW": 1920,
    "targetH": 1080,
    "units": "pixels"
  },
  "expected_outputs": {
    "scale": 1,
    "fittedWidth": 1920,
    "fittedHeight": 1080,
    "barLeft": 0,
    "barRight": 0,
    "barTop": 0,
    "barBottom": 0,
    "cropPixels": 0
  },
  "working": "scale=min(1920/1920,1080/1080)=min(1,1)=1. fittedWidth=1920*1=1920. fittedHeight=1080*1=1080. leftoverWidth=1920-1920=0, so left/right bars=0/2=0 each. leftoverHeight=1080-1080=0, so top/bottom bars=0/2=0 each. No cropping occurs, so cropPixels=0."
}

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-tranche5/tranche5-results.json