Description
Return cap/line share, ascender+descender occupiedHeight, and lineHeight minus that total.
Typography combines several distinct scales: font size describes an em scale, cap height describes a font metric, leading describes baseline spacing, and variable-font axes select design coordinates. Ratios between them require an explicit convention.
Return cap/line share, ascender+descender occupiedHeight, and lineHeight minus that total.
When to use this tool
Use Type Capheight Lineheight Share when you need to compare supplied type metrics or font-axis values on a consistent basis.
How to use the tool and how it works
- Enter capHeight, lineHeight, ascenderHeight, descenderDepth. Use the units and conventions below.
- Run the tool. Correct any format, range, or cross-field input error before interpreting the output.
- Read capShare, occupiedHeight, remainingLeading. Use the output convention below.
Require nonnegative capHeight, ascenderHeight, and descenderDepth and positive lineHeight. Return cap/line share, ascender+descender occupiedHeight, and lineHeight minus that total.1
| Input field | Meaning and units | Accepted input |
|---|---|---|
| capHeight | Cap Height | Required. Finite number; minimum 0. |
| lineHeight | Line Height | Required. Finite number; strictly above 0. |
| ascenderHeight | Ascender Height | Required. Finite number; minimum 0. |
| descenderDepth | Descender Depth | Required. Finite number; minimum 0. |
| Output field | Interpretation | Returned shape |
|---|---|---|
| capShare | Cap Share | Required. Finite number. |
| occupiedHeight | Occupied Height | Required. Finite number. |
| remainingLeading | Remaining Leading | Required. Finite number. |
{
"input": {
"capHeight": 7,
"lineHeight": 12,
"ascenderHeight": 9,
"descenderDepth": 2
},
"output": {
"capShare": 0.5833333333333334,
"occupiedHeight": 11,
"remainingLeading": 1
}
}Limitations and assumptions
- Measurements share a unit; negative remainingLeading and capShare above one are retained without evaluating actual glyphs, clipping, readability, or font correctness.
- 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
Read actual font metrics and variation tables when available, then proof the text in its intended renderer. A metric calculation cannot replace shaping, glyph inspection, or an actual layout test.
References
Similar or alternative tools
- Type Cap Height Xheight Ratio
Return xHeight/capHeight and scale both design-unit heights by fontPixels/unitsPerEm.
- Type Size Leading Ratio
Convert both to points and return reciprocal type-size/leading ratios.