Math parameters

Correspondance in TeX OpenType suggested default Firefox fallback WebKit fallback Chromium fallback MathML/CSS proposal
rule thickness ξ8 ?? height of U+00AF MACRON if in the interval (0, x-height) or 40/430.556 x-height otherwise. 0.05em Same as WebKit ??
scriptPercentScaleDown Per-font macro 80% Unused Unused Unused 0.8
scriptScriptPercentScaleDown Per-font macro 60% Unused Unused Unused 0.6
delimitedSubFormulaMinHeight σ21 normal line height × 1.5 Unused Unused Unused Unused
displayOperatorMinHeight ?? None 0, additional heuristic 0, additional heuristic Unused 0??, with additional heuristic
mathLeading Unused None Unused Unused Unused Unused
axisHeight σ22 (axis height) None ½ the height of U+2212 MINUS SIGN if in the interval (0, x-height) ; otherwise 250/430.556 the x-height. ½ x-height Same as WebKit ??
accentBaseHeight σ5 (x-height) x‑height of the font (os2.sxHeight) plus any possible overshots. x-height x-height x-height??
flattenedAccentBaseHeight ?? (capital height) cap height of the font (os2.sCapHeight) Unused Unused Unused Unused
subscriptShiftDown σ16, σ17 os2.ySubscriptYOffset 150/430.556 x-height for msub and 247.217/430.556 x-height ⅓ x-height os2.ySubscriptYOffset??
subscriptTopMax ⅘σ5 ⅘ x-height ⅘ x-height ⅘ x-height ⅘ x-height??
subscriptBaselineDropMin σ22 None 50/430.556 x-height ½ x-height ??
superscriptShiftUp σ13, σ14 os2.ySuperscriptYOffset 412.892/430.556 x-height in display mode and scriptlevel 0, 362.892/430.556 x-height otherwise x-height os2.ySuperscriptYOffset??
superscriptShiftUpCramped σ15 None 288.889/430.556 x-height Unused Unused ??
superscriptBottomMin ¼σ5 ¼ x-height ¼ x-height ¼ x-height ¼ x-height
superscriptBaselineDropMax σ18 None 386.108/430.556 x-height ½ x-height
subSuperscriptGapMin 4ξ8 4 × default rule thickness 4 × rule thickness 1/5 em
superscriptBottomMaxWithSubscript ⅘σ5 ⅘ x-height ⅘ x-height ⅘ x-height ⅘ x-height?
spaceAfterScript \scriptspace 0.5pt for a 12pt font. 0.5pt 1/5 em
upperLimitGapMin ξ9 None 111.111/430.556f x-height 3 rule thickness
upperLimitBaselineRiseMin ξ11 None 200/430.556f x-height 0
lowerLimitGapMin ξ10 None 166.667/430.556f x-height 3 rulethickness
lowerLimitBaselineDropMin ξ12 None 600/430.556f x-height 0
stackTopShiftUp σ10 None 443.731/430.556 x-height 0
stackTopDisplayStyleShiftUp σ8 None 676.508/430.556 x-height 0
stackBottomShiftDown σ12 None 344.841/430.556 x-height 0
stackBottomDisplayStyleShiftDown σ11 None 685.951/430.556 x-height 0
stackGapMin 3ξ8 3 × default rule thickness 3 × rule thickness 3 × rule thickness
stackDisplayStyleGapMin 7ξ8 7 × default rule thickness 7 × rule thickness 3 × rule thickness
stretchStackTopShiftUp ξ11 None Unused 0
stretchStackBottomShiftDown ξ12 None Unused 0
stretchStackGapAboveMin ξ9 Same value as upperLimitGapMin Unused 3 rule thickness
stretchStackGapBelowMin ξ10 Same value as lowerLimitGapMin. Unused 3 rule thickness
fractionNumeratorShiftUp σ9 None 393.732/430.556 x-height 0
fractionNumeratorDisplayStyleShiftUp σ8 Same value as stackTopDisplayStyleShiftUp 676.508/430.556 x-height 0
fractionDenominatorShiftDown σ12 None 344.841/430.556 x-height 0
fractionDenominatorDisplayStyleShiftDown σ11 Same value as stackBottomDisplayStyleShiftDown 685.951/430.556 x-height 0
fractionNumeratorGapMin ξ8 default rule thickness rule thickness + 1px rule thickness
fractionNumDisplayStyleGapMin 3ξ8 3 × default rule thickness 3 × rule thickness 3 × rule thickness
fractionRuleThickness ξ8 default rule thickness rule thickness rule thickness
fractionDenominatorGapMin ξ8 default rule thickness rule thickness + 1px rule thickness
fractionDenomDisplayStyleGapMin 3ξ8 3 × default rule thickness 3 × rule thickness 3 × rule thickness
skewedFractionHorizontalGap ?? None Unused Unused Unused Unused
skewedFractionVerticalGap ?? None Unused Unused Unused Unused
overbarVerticalGap 3ξ8 3 × default rule thickness Unused 0
overbarRuleThickness ξ8 default rule thickness Unused Unused Unused Unused
overbarExtraAscender ξ8 default rule thickness Unused rule thickness
underbarVerticalGap 3ξ8 3 × default rule thickness Unused 3 rule thickness
underbarRuleThickness ξ8 default rule thickness Unused Unused Unused Unused
underbarExtraDescender ξ8 default rule thickness Unused rule thickness
radicalVerticalGap 5/4 ξ8 1¼ default rule thickness 5/4 rule thickness 5/4 rule thickness
radicalDisplayStyleVerticalGap ξ8 + ¼σ5 default rule thickness + ¼ x-height rule thickness + ¼ x-height rule thickness + ¼ x-height
radicalRuleThickness ξ8 default rule thickness rule thickness rule thickness
radicalExtraAscender ξ8 same value as radicalRuleThickness 0.2em rule thickness
radicalKernBeforeDegree Hardcoded in root macro (e.g. 5/18 em) None Special adjustment if missing 5/18 em
radicalKernAfterDegree Hardcoded in root macro (e.g. −10/18 em) −10/18 of em −1.35 x-height −10/18 em
radicalDegreeBottomRaisePercent Hardcoded in root macro (e.g. .6) 60% 0.6 0.6