Description
Calculate a variable font's optical-size axis offset from a supplied reference coordinate.
Graphic-design metadata distinguishes font metrics, variable-font axes, fill rules, color labels and design-token units. Numeric axis differences and text labels do not render a font or apply a color profile. The source convention must match before comparing metrics or resolving a design-system reference.
Calculate a variable font's optical-size axis offset from a supplied reference coordinate.
When to use this tool
Use Variable Font Optical Size Reference Pair when checking the stated font, color or design-token convention.
How to use the tool and how it works
- Enter opticalSizeAxisValue, suppliedReferenceAxisValue. Use the units and conventions below.
- Run the tool. Correct any format, range, or cross-field input error before interpreting the output.
- Read axisValueDifference. Use the output convention below.
Return opticalSizeAxisValue-suppliedReferenceAxisValue as a signed axis-coordinate difference.1
| Input field | Meaning and units | Accepted input |
|---|---|---|
| opticalSizeAxisValue | Supplied variable-font axis coordinate; no font axis range is loaded. | Required. Finite number. |
| suppliedReferenceAxisValue | Supplied Reference Axis Value | Required. Finite number. |
| Output field | Interpretation | Returned shape |
|---|---|---|
| axisValueDifference | Axis Value Difference | Required. Finite number. |
{
"input": {
"opticalSizeAxisValue": 14,
"suppliedReferenceAxisValue": 12
},
"output": {
"axisValueDifference": 2
}
}Limitations and assumptions
- No font is loaded and no opsz range, automatic optical sizing, text appearance or suitable axis setting is determined.
- Inputs must satisfy both the field types and the cross-field conditions above. Invalid input causes an error; a successful false flag or documented placeholder is a different result.
- Numeric calculations use binary floating point unless exact decimal-integer arithmetic is explicitly stated. No hidden measurement tolerance or decimal rounding is added; nonfinite or out-of-contract results are rejected. Numeric signed-zero results are exported as zero.
Alternative or Complementary methods
Inspect actual fonts, rendered paths, color profiles and the complete applicable design-system specification for visual or production decisions.
References
Similar or alternative tools
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Record whether outlined text uses the nonzero or evenodd fill rule.