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/* eslint no-unused-vars:0 */
var Style = require("./Style");
/**
* This file contains metrics regarding fonts and individual symbols. The sigma
* and xi variables, as well as the metricMap map contain data extracted from
* TeX, TeX font metrics, and the TTF files. These data are then exposed via the
* `metrics` variable and the getCharacterMetrics function.
*/
// These font metrics are extracted from TeX by using
// \font\a=cmmi10
// \showthe\fontdimenX\a
// where X is the corresponding variable number. These correspond to the font
// parameters of the symbol fonts. In TeX, there are actually three sets of
// dimensions, one for each of textstyle, scriptstyle, and scriptscriptstyle,
// but we only use the textstyle ones, and scale certain dimensions accordingly.
// See the TeXbook, page 441.
var sigma1 = 0.025;
var sigma2 = 0;
var sigma3 = 0;
var sigma4 = 0;
var sigma5 = 0.431;
var sigma6 = 1;
var sigma7 = 0;
var sigma8 = 0.677;
var sigma9 = 0.394;
var sigma10 = 0.444;
var sigma11 = 0.686;
var sigma12 = 0.345;
var sigma13 = 0.413;
var sigma14 = 0.363;
var sigma15 = 0.289;
var sigma16 = 0.150;
var sigma17 = 0.247;
var sigma18 = 0.386;
var sigma19 = 0.050;
var sigma20 = 2.390;
var sigma21 = 1.01;
var sigma21Script = 0.81;
var sigma21ScriptScript = 0.71;
var sigma22 = 0.250;
// These font metrics are extracted from TeX by using
// \font\a=cmex10
// \showthe\fontdimenX\a
// where X is the corresponding variable number. These correspond to the font
// parameters of the extension fonts (family 3). See the TeXbook, page 441.
var xi1 = 0;
var xi2 = 0;
var xi3 = 0;
var xi4 = 0;
var xi5 = 0.431;
var xi6 = 1;
var xi7 = 0;
var xi8 = 0.04;
var xi9 = 0.111;
var xi10 = 0.166;
var xi11 = 0.2;
var xi12 = 0.6;
var xi13 = 0.1;
// This value determines how large a pt is, for metrics which are defined in
// terms of pts.
// This value is also used in katex.less; if you change it make sure the values
// match.
var ptPerEm = 10.0;
// The space between adjacent `|` columns in an array definition. From
// `\showthe\doublerulesep` in LaTeX.
var doubleRuleSep = 2.0 / ptPerEm;
/**
* This is just a mapping from common names to real metrics
*/
var metrics = {
xHeight: sigma5,
quad: sigma6,
num1: sigma8,
num2: sigma9,
num3: sigma10,
denom1: sigma11,
denom2: sigma12,
sup1: sigma13,
sup2: sigma14,
sup3: sigma15,
sub1: sigma16,
sub2: sigma17,
supDrop: sigma18,
subDrop: sigma19,
axisHeight: sigma22,
defaultRuleThickness: xi8,
bigOpSpacing1: xi9,
bigOpSpacing2: xi10,
bigOpSpacing3: xi11,
bigOpSpacing4: xi12,
bigOpSpacing5: xi13,
ptPerEm: ptPerEm,
emPerEx: sigma5 / sigma6,
doubleRuleSep: doubleRuleSep,
// TODO(alpert): Missing parallel structure here. We should probably add
// style-specific metrics for all of these.
delim1: sigma20,
getDelim2: function(style) {
if (style.size === Style.TEXT.size) {
return sigma21;
} else if (style.size === Style.SCRIPT.size) {
return sigma21Script;
} else if (style.size === Style.SCRIPTSCRIPT.size) {
return sigma21ScriptScript;
}
throw new Error("Unexpected style size: " + style.size);
},
};
// This map contains a mapping from font name and character code to character
// metrics, including height, depth, italic correction, and skew (kern from the
// character to the corresponding \skewchar)
// This map is generated via `make metrics`. It should not be changed manually.
var metricMap = require("./fontMetricsData");
/**
* This function is a convenience function for looking up information in the
* metricMap table. It takes a character as a string, and a style.
*
* Note: the `width` property may be undefined if fontMetricsData.js wasn't
* built using `Make extended_metrics`.
*/
var getCharacterMetrics = function(character, style) {
var metrics = metricMap[style][character.charCodeAt(0)];
if (metrics) {
return {
depth: metrics[0],
height: metrics[1],
italic: metrics[2],
skew: metrics[3],
width: metrics[4],
};
}
};
module.exports = {
metrics: metrics,
getCharacterMetrics: getCharacterMetrics,
};
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