Files
KaTeX/src/buildHTML.js
Kevin Barabash c6647e3303 Added support for \not (#140)
* Added support for \not

* fix grammar in comment
2017-08-23 13:24:17 -04:00

1776 lines
63 KiB
JavaScript

/* eslint no-console:0 */
/**
* This file does the main work of building a domTree structure from a parse
* tree. The entry point is the `buildHTML` function, which takes a parse tree.
* Then, the buildExpression, buildGroup, and various groupTypes functions are
* called, to produce a final HTML tree.
*/
import ParseError from "./ParseError";
import Style from "./Style";
import buildCommon, { makeSpan } from "./buildCommon";
import delimiter from "./delimiter";
import domTree from "./domTree";
import units from "./units";
import utils from "./utils";
import stretchy from "./stretchy";
const isSpace = function(node) {
return node instanceof domTree.span && node.classes[0] === "mspace";
};
// Binary atoms (first class `mbin`) change into ordinary atoms (`mord`)
// depending on their surroundings. See TeXbook pg. 442-446, Rules 5 and 6,
// and the text before Rule 19.
const isBin = function(node) {
return node && node.classes[0] === "mbin";
};
const isBinLeftCanceller = function(node, isRealGroup) {
// TODO: This code assumes that a node's math class is the first element
// of its `classes` array. A later cleanup should ensure this, for
// instance by changing the signature of `makeSpan`.
if (node) {
return utils.contains(["mbin", "mopen", "mrel", "mop", "mpunct"],
node.classes[0]);
} else {
return isRealGroup;
}
};
const isBinRightCanceller = function(node, isRealGroup) {
if (node) {
return utils.contains(["mrel", "mclose", "mpunct"], node.classes[0]);
} else {
return isRealGroup;
}
};
/**
* Splice out any spaces from `children` starting at position `i`, and return
* the spliced-out array. Returns null if `children[i]` does not exist or is not
* a space.
*/
const spliceSpaces = function(children, i) {
let j = i;
while (j < children.length && isSpace(children[j])) {
j++;
}
if (j === i) {
return null;
} else {
return children.splice(i, j - i);
}
};
/**
* Take a list of nodes, build them in order, and return a list of the built
* nodes. documentFragments are flattened into their contents, so the
* returned list contains no fragments. `isRealGroup` is true if `expression`
* is a real group (no atoms will be added on either side), as opposed to
* a partial group (e.g. one created by \color).
*/
const buildExpression = function(expression, options, isRealGroup) {
// Parse expressions into `groups`.
const groups = [];
for (let i = 0; i < expression.length; i++) {
const group = expression[i];
const output = buildGroup(group, options);
if (output instanceof domTree.documentFragment) {
Array.prototype.push.apply(groups, output.children);
} else {
groups.push(output);
}
}
// At this point `groups` consists entirely of `symbolNode`s and `span`s.
// Explicit spaces (e.g., \;, \,) should be ignored with respect to atom
// spacing (e.g., "add thick space between mord and mrel"). Since CSS
// adjacency rules implement atom spacing, spaces should be invisible to
// CSS. So we splice them out of `groups` and into the atoms themselves.
for (let i = 0; i < groups.length; i++) {
const spaces = spliceSpaces(groups, i);
if (spaces) {
// Splicing of spaces may have removed all remaining groups.
if (i < groups.length) {
// If there is a following group, move space within it.
if (groups[i] instanceof domTree.symbolNode) {
groups[i] = makeSpan([].concat(groups[i].classes),
[groups[i]]);
}
buildCommon.prependChildren(groups[i], spaces);
} else {
// Otherwise, put any spaces back at the end of the groups.
Array.prototype.push.apply(groups, spaces);
break;
}
}
}
// Binary operators change to ordinary symbols in some contexts.
for (let i = 0; i < groups.length; i++) {
if (isBin(groups[i])
&& (isBinLeftCanceller(groups[i - 1], isRealGroup)
|| isBinRightCanceller(groups[i + 1], isRealGroup))) {
groups[i].classes[0] = "mord";
}
}
// Process \\not commands within the group.
// TODO(kevinb): Handle multiple \\not commands in a row.
// TODO(kevinb): Handle \\not{abc} correctly. The \\not should appear over
// the 'a' instead of the 'c'.
for (let i = 0; i < groups.length; i++) {
if (groups[i].value === "\u0338" && i + 1 < groups.length) {
const children = groups.slice(i, i + 2);
children[0].classes = ["mainrm"];
// \u0338 is a combining glyph so we could reorder the children so
// that it comes after the other glyph. This works correctly on
// most browsers except for Safari. Instead we absolutely position
// the glyph and set its right side to match that of the other
// glyph which is visually equivalent.
children[0].style.position = "absolute";
children[0].style.right = "0";
// Copy the classes from the second glyph to the new container.
// This is so it behaves the same as though there was no \\not.
const classes = groups[i + 1].classes;
const container = makeSpan(classes, children);
// LaTeX adds a space between ords separated by a \\not.
if (classes.indexOf("mord") !== -1) {
// \glue(\thickmuskip) 2.77771 plus 2.77771
container.style.paddingLeft = "0.277771em";
}
// Ensure that the \u0338 is positioned relative to the container.
container.style.position = "relative";
groups.splice(i, 2, container);
}
}
return groups;
};
// Return math atom class (mclass) of a domTree.
const getTypeOfDomTree = function(node) {
if (node instanceof domTree.documentFragment) {
if (node.children.length) {
return getTypeOfDomTree(
node.children[node.children.length - 1]);
}
} else {
if (utils.contains([
"mord", "mop", "mbin", "mrel", "mopen", "mclose",
"mpunct", "minner",
], node.classes[0])) {
return node.classes[0];
}
}
return null;
};
/**
* Sometimes, groups perform special rules when they have superscripts or
* subscripts attached to them. This function lets the `supsub` group know that
* its inner element should handle the superscripts and subscripts instead of
* handling them itself.
*/
const shouldHandleSupSub = function(group, options) {
if (!group.value.base) {
return false;
} else {
const base = group.value.base;
if (base.type === "op") {
// Operators handle supsubs differently when they have limits
// (e.g. `\displaystyle\sum_2^3`)
return base.value.limits &&
(options.style.size === Style.DISPLAY.size ||
base.value.alwaysHandleSupSub);
} else if (base.type === "accent") {
return isCharacterBox(base.value.base);
} else if (base.type === "horizBrace") {
const isSup = (group.value.sub ? false : true);
return (isSup === base.value.isOver);
} else {
return null;
}
}
};
/**
* Sometimes we want to pull out the innermost element of a group. In most
* cases, this will just be the group itself, but when ordgroups and colors have
* a single element, we want to pull that out.
*/
const getBaseElem = function(group) {
if (!group) {
return false;
} else if (group.type === "ordgroup") {
if (group.value.length === 1) {
return getBaseElem(group.value[0]);
} else {
return group;
}
} else if (group.type === "color") {
if (group.value.value.length === 1) {
return getBaseElem(group.value.value[0]);
} else {
return group;
}
} else if (group.type === "font") {
return getBaseElem(group.value.body);
} else {
return group;
}
};
/**
* TeXbook algorithms often reference "character boxes", which are simply groups
* with a single character in them. To decide if something is a character box,
* we find its innermost group, and see if it is a single character.
*/
const isCharacterBox = function(group) {
const baseElem = getBaseElem(group);
// These are all they types of groups which hold single characters
return baseElem.type === "mathord" ||
baseElem.type === "textord" ||
baseElem.type === "bin" ||
baseElem.type === "rel" ||
baseElem.type === "inner" ||
baseElem.type === "open" ||
baseElem.type === "close" ||
baseElem.type === "punct";
};
const makeNullDelimiter = function(options, classes) {
const moreClasses = ["nulldelimiter"].concat(options.baseSizingClasses());
return makeSpan(classes.concat(moreClasses));
};
/**
* This is a map of group types to the function used to handle that type.
* Simpler types come at the beginning, while complicated types come afterwards.
*/
const groupTypes = {};
groupTypes.mathord = function(group, options) {
return buildCommon.makeOrd(group, options, "mathord");
};
groupTypes.textord = function(group, options) {
return buildCommon.makeOrd(group, options, "textord");
};
groupTypes.bin = function(group, options) {
return buildCommon.mathsym(
group.value, group.mode, options, ["mbin"]);
};
groupTypes.rel = function(group, options) {
return buildCommon.mathsym(
group.value, group.mode, options, ["mrel"]);
};
groupTypes.open = function(group, options) {
return buildCommon.mathsym(
group.value, group.mode, options, ["mopen"]);
};
groupTypes.close = function(group, options) {
return buildCommon.mathsym(
group.value, group.mode, options, ["mclose"]);
};
groupTypes.inner = function(group, options) {
return buildCommon.mathsym(
group.value, group.mode, options, ["minner"]);
};
groupTypes.punct = function(group, options) {
return buildCommon.mathsym(
group.value, group.mode, options, ["mpunct"]);
};
groupTypes.ordgroup = function(group, options) {
return makeSpan(["mord"],
buildExpression(group.value, options, true),
options
);
};
groupTypes.text = function(group, options) {
const newOptions = options.withFont(group.value.style);
const inner = buildExpression(group.value.body, newOptions, true);
for (let i = 0; i < inner.length - 1; i++) {
if (inner[i].tryCombine(inner[i + 1])) {
inner.splice(i + 1, 1);
i--;
}
}
return makeSpan(["mord", "text"],
inner, newOptions);
};
groupTypes.color = function(group, options) {
const elements = buildExpression(
group.value.value,
options.withColor(group.value.color),
false
);
// \color isn't supposed to affect the type of the elements it contains.
// To accomplish this, we wrap the results in a fragment, so the inner
// elements will be able to directly interact with their neighbors. For
// example, `\color{red}{2 +} 3` has the same spacing as `2 + 3`
return new buildCommon.makeFragment(elements);
};
groupTypes.supsub = function(group, options) {
// Superscript and subscripts are handled in the TeXbook on page
// 445-446, rules 18(a-f).
// Here is where we defer to the inner group if it should handle
// superscripts and subscripts itself.
if (shouldHandleSupSub(group, options)) {
return groupTypes[group.value.base.type](group, options);
}
const base = buildGroup(group.value.base, options);
let supm;
let subm;
const metrics = options.fontMetrics();
let newOptions;
// Rule 18a
let supShift = 0;
let subShift = 0;
if (group.value.sup) {
newOptions = options.havingStyle(options.style.sup());
supm = buildGroup(group.value.sup, newOptions, options);
if (!isCharacterBox(group.value.base)) {
supShift = base.height - newOptions.fontMetrics().supDrop
* newOptions.sizeMultiplier / options.sizeMultiplier;
}
}
if (group.value.sub) {
newOptions = options.havingStyle(options.style.sub());
subm = buildGroup(group.value.sub, newOptions, options);
if (!isCharacterBox(group.value.base)) {
subShift = base.depth + newOptions.fontMetrics().subDrop
* newOptions.sizeMultiplier / options.sizeMultiplier;
}
}
// Rule 18c
let minSupShift;
if (options.style === Style.DISPLAY) {
minSupShift = metrics.sup1;
} else if (options.style.cramped) {
minSupShift = metrics.sup3;
} else {
minSupShift = metrics.sup2;
}
// scriptspace is a font-size-independent size, so scale it
// appropriately
const multiplier = options.sizeMultiplier;
const scriptspace =
(0.5 / metrics.ptPerEm) / multiplier + "em";
let supsub;
if (!group.value.sup) {
// Rule 18b
subShift = Math.max(
subShift, metrics.sub1,
subm.height - 0.8 * metrics.xHeight);
const vlistElem = [{type: "elem", elem: subm, marginRight: scriptspace}];
// Subscripts shouldn't be shifted by the base's italic correction.
// Account for that by shifting the subscript back the appropriate
// amount. Note we only do this when the base is a single symbol.
if (base instanceof domTree.symbolNode) {
vlistElem[0].marginLeft = -base.italic + "em";
}
supsub = buildCommon.makeVList(vlistElem, "shift", subShift, options);
} else if (!group.value.sub) {
// Rule 18c, d
supShift = Math.max(supShift, minSupShift,
supm.depth + 0.25 * metrics.xHeight);
supsub = buildCommon.makeVList([
{type: "elem", elem: supm, marginRight: scriptspace},
], "shift", -supShift, options);
} else {
supShift = Math.max(
supShift, minSupShift, supm.depth + 0.25 * metrics.xHeight);
subShift = Math.max(subShift, metrics.sub2);
const ruleWidth = metrics.defaultRuleThickness;
// Rule 18e
if ((supShift - supm.depth) - (subm.height - subShift) <
4 * ruleWidth) {
subShift = 4 * ruleWidth - (supShift - supm.depth) + subm.height;
const psi = 0.8 * metrics.xHeight - (supShift - supm.depth);
if (psi > 0) {
supShift += psi;
subShift -= psi;
}
}
const vlistElem = [
{type: "elem", elem: subm, shift: subShift, marginRight: scriptspace},
{type: "elem", elem: supm, shift: -supShift, marginRight: scriptspace},
];
// See comment above about subscripts not being shifted
if (base instanceof domTree.symbolNode) {
vlistElem[0].marginLeft = -base.italic + "em";
}
supsub = buildCommon.makeVList(vlistElem, "individualShift", null, options);
}
// We ensure to wrap the supsub vlist in a span.msupsub to reset text-align
const mclass = getTypeOfDomTree(base) || "mord";
return makeSpan([mclass],
[base, makeSpan(["msupsub"], [supsub])],
options);
};
groupTypes.genfrac = function(group, options) {
// Fractions are handled in the TeXbook on pages 444-445, rules 15(a-e).
// Figure out what style this fraction should be in based on the
// function used
let style = options.style;
if (group.value.size === "display") {
style = Style.DISPLAY;
} else if (group.value.size === "text") {
style = Style.TEXT;
}
const nstyle = style.fracNum();
const dstyle = style.fracDen();
let newOptions;
newOptions = options.havingStyle(nstyle);
const numerm = buildGroup(group.value.numer, newOptions, options);
newOptions = options.havingStyle(dstyle);
const denomm = buildGroup(group.value.denom, newOptions, options);
let rule;
let ruleWidth;
let ruleSpacing;
if (group.value.hasBarLine) {
rule = makeLineSpan("frac-line", options);
ruleWidth = rule.height;
ruleSpacing = rule.height;
} else {
rule = null;
ruleWidth = 0;
ruleSpacing = options.fontMetrics().defaultRuleThickness;
}
// Rule 15b
let numShift;
let clearance;
let denomShift;
if (style.size === Style.DISPLAY.size) {
numShift = options.fontMetrics().num1;
if (ruleWidth > 0) {
clearance = 3 * ruleSpacing;
} else {
clearance = 7 * ruleSpacing;
}
denomShift = options.fontMetrics().denom1;
} else {
if (ruleWidth > 0) {
numShift = options.fontMetrics().num2;
clearance = ruleSpacing;
} else {
numShift = options.fontMetrics().num3;
clearance = 3 * ruleSpacing;
}
denomShift = options.fontMetrics().denom2;
}
let frac;
if (ruleWidth === 0) {
// Rule 15c
const candidateClearance =
(numShift - numerm.depth) - (denomm.height - denomShift);
if (candidateClearance < clearance) {
numShift += 0.5 * (clearance - candidateClearance);
denomShift += 0.5 * (clearance - candidateClearance);
}
frac = buildCommon.makeVList([
{type: "elem", elem: denomm, shift: denomShift},
{type: "elem", elem: numerm, shift: -numShift},
], "individualShift", null, options);
} else {
// Rule 15d
const axisHeight = options.fontMetrics().axisHeight;
if ((numShift - numerm.depth) - (axisHeight + 0.5 * ruleWidth) <
clearance) {
numShift +=
clearance - ((numShift - numerm.depth) -
(axisHeight + 0.5 * ruleWidth));
}
if ((axisHeight - 0.5 * ruleWidth) - (denomm.height - denomShift) <
clearance) {
denomShift +=
clearance - ((axisHeight - 0.5 * ruleWidth) -
(denomm.height - denomShift));
}
const midShift = -(axisHeight - 0.5 * ruleWidth);
frac = buildCommon.makeVList([
{type: "elem", elem: denomm, shift: denomShift},
{type: "elem", elem: rule, shift: midShift},
{type: "elem", elem: numerm, shift: -numShift},
], "individualShift", null, options);
}
// Since we manually change the style sometimes (with \dfrac or \tfrac),
// account for the possible size change here.
newOptions = options.havingStyle(style);
frac.height *= newOptions.sizeMultiplier / options.sizeMultiplier;
frac.depth *= newOptions.sizeMultiplier / options.sizeMultiplier;
// Rule 15e
let delimSize;
if (style.size === Style.DISPLAY.size) {
delimSize = options.fontMetrics().delim1;
} else {
delimSize = options.fontMetrics().delim2;
}
let leftDelim;
let rightDelim;
if (group.value.leftDelim == null) {
leftDelim = makeNullDelimiter(options, ["mopen"]);
} else {
leftDelim = delimiter.customSizedDelim(
group.value.leftDelim, delimSize, true,
options.havingStyle(style), group.mode, ["mopen"]);
}
if (group.value.rightDelim == null) {
rightDelim = makeNullDelimiter(options, ["mclose"]);
} else {
rightDelim = delimiter.customSizedDelim(
group.value.rightDelim, delimSize, true,
options.havingStyle(style), group.mode, ["mclose"]);
}
return makeSpan(
["mord"].concat(newOptions.sizingClasses(options)),
[leftDelim, makeSpan(["mfrac"], [frac]), rightDelim],
options);
};
groupTypes.array = function(group, options) {
let r;
let c;
const nr = group.value.body.length;
let nc = 0;
let body = new Array(nr);
// Horizontal spacing
const pt = 1 / options.fontMetrics().ptPerEm;
const arraycolsep = 5 * pt; // \arraycolsep in article.cls
// Vertical spacing
const baselineskip = 12 * pt; // see size10.clo
// Default \jot from ltmath.dtx
// TODO(edemaine): allow overriding \jot via \setlength (#687)
const jot = 3 * pt;
// Default \arraystretch from lttab.dtx
// TODO(gagern): may get redefined once we have user-defined macros
const arraystretch = utils.deflt(group.value.arraystretch, 1);
const arrayskip = arraystretch * baselineskip;
const arstrutHeight = 0.7 * arrayskip; // \strutbox in ltfsstrc.dtx and
const arstrutDepth = 0.3 * arrayskip; // \@arstrutbox in lttab.dtx
let totalHeight = 0;
for (r = 0; r < group.value.body.length; ++r) {
const inrow = group.value.body[r];
let height = arstrutHeight; // \@array adds an \@arstrut
let depth = arstrutDepth; // to each tow (via the template)
if (nc < inrow.length) {
nc = inrow.length;
}
const outrow = new Array(inrow.length);
for (c = 0; c < inrow.length; ++c) {
const elt = buildGroup(inrow[c], options);
if (depth < elt.depth) {
depth = elt.depth;
}
if (height < elt.height) {
height = elt.height;
}
outrow[c] = elt;
}
let gap = 0;
if (group.value.rowGaps[r]) {
gap = units.calculateSize(group.value.rowGaps[r].value, options);
if (gap > 0) { // \@argarraycr
gap += arstrutDepth;
if (depth < gap) {
depth = gap; // \@xargarraycr
}
gap = 0;
}
}
// In AMS multiline environments such as aligned and gathered, rows
// correspond to lines that have additional \jot added to the
// \baselineskip via \openup.
if (group.value.addJot) {
depth += jot;
}
outrow.height = height;
outrow.depth = depth;
totalHeight += height;
outrow.pos = totalHeight;
totalHeight += depth + gap; // \@yargarraycr
body[r] = outrow;
}
const offset = totalHeight / 2 + options.fontMetrics().axisHeight;
const colDescriptions = group.value.cols || [];
const cols = [];
let colSep;
let colDescrNum;
for (c = 0, colDescrNum = 0;
// Continue while either there are more columns or more column
// descriptions, so trailing separators don't get lost.
c < nc || colDescrNum < colDescriptions.length;
++c, ++colDescrNum) {
let colDescr = colDescriptions[colDescrNum] || {};
let firstSeparator = true;
while (colDescr.type === "separator") {
// If there is more than one separator in a row, add a space
// between them.
if (!firstSeparator) {
colSep = makeSpan(["arraycolsep"], []);
colSep.style.width =
options.fontMetrics().doubleRuleSep + "em";
cols.push(colSep);
}
if (colDescr.separator === "|") {
const separator = makeSpan(
["vertical-separator"],
[]);
separator.style.height = totalHeight + "em";
separator.style.verticalAlign =
-(totalHeight - offset) + "em";
cols.push(separator);
} else {
throw new ParseError(
"Invalid separator type: " + colDescr.separator);
}
colDescrNum++;
colDescr = colDescriptions[colDescrNum] || {};
firstSeparator = false;
}
if (c >= nc) {
continue;
}
let sepwidth;
if (c > 0 || group.value.hskipBeforeAndAfter) {
sepwidth = utils.deflt(colDescr.pregap, arraycolsep);
if (sepwidth !== 0) {
colSep = makeSpan(["arraycolsep"], []);
colSep.style.width = sepwidth + "em";
cols.push(colSep);
}
}
let col = [];
for (r = 0; r < nr; ++r) {
const row = body[r];
const elem = row[c];
if (!elem) {
continue;
}
const shift = row.pos - offset;
elem.depth = row.depth;
elem.height = row.height;
col.push({type: "elem", elem: elem, shift: shift});
}
col = buildCommon.makeVList(col, "individualShift", null, options);
col = makeSpan(
["col-align-" + (colDescr.align || "c")],
[col]);
cols.push(col);
if (c < nc - 1 || group.value.hskipBeforeAndAfter) {
sepwidth = utils.deflt(colDescr.postgap, arraycolsep);
if (sepwidth !== 0) {
colSep = makeSpan(["arraycolsep"], []);
colSep.style.width = sepwidth + "em";
cols.push(colSep);
}
}
}
body = makeSpan(["mtable"], cols);
return makeSpan(["mord"], [body], options);
};
groupTypes.spacing = function(group, options) {
if (group.value === "\\ " || group.value === "\\space" ||
group.value === " " || group.value === "~") {
// Spaces are generated by adding an actual space. Each of these
// things has an entry in the symbols table, so these will be turned
// into appropriate outputs.
if (group.mode === "text") {
return buildCommon.makeOrd(group, options, "textord");
} else {
return makeSpan(["mspace"],
[buildCommon.mathsym(group.value, group.mode, options)],
options);
}
} else {
// Other kinds of spaces are of arbitrary width. We use CSS to
// generate these.
return makeSpan(
["mspace", buildCommon.spacingFunctions[group.value].className],
[], options);
}
};
groupTypes.llap = function(group, options) {
const inner = makeSpan(
["inner"], [buildGroup(group.value.body, options)]);
const fix = makeSpan(["fix"], []);
return makeSpan(
["mord", "llap"], [inner, fix], options);
};
groupTypes.rlap = function(group, options) {
const inner = makeSpan(
["inner"], [buildGroup(group.value.body, options)]);
const fix = makeSpan(["fix"], []);
return makeSpan(
["mord", "rlap"], [inner, fix], options);
};
groupTypes.op = function(group, options) {
// Operators are handled in the TeXbook pg. 443-444, rule 13(a).
let supGroup;
let subGroup;
let hasLimits = false;
if (group.type === "supsub") {
// If we have limits, supsub will pass us its group to handle. Pull
// out the superscript and subscript and set the group to the op in
// its base.
supGroup = group.value.sup;
subGroup = group.value.sub;
group = group.value.base;
hasLimits = true;
}
const style = options.style;
// Most operators have a large successor symbol, but these don't.
const noSuccessor = [
"\\smallint",
];
let large = false;
if (style.size === Style.DISPLAY.size &&
group.value.symbol &&
!utils.contains(noSuccessor, group.value.body)) {
// Most symbol operators get larger in displaystyle (rule 13)
large = true;
}
let base;
if (group.value.symbol) {
// If this is a symbol, create the symbol.
const fontName = large ? "Size2-Regular" : "Size1-Regular";
base = buildCommon.makeSymbol(
group.value.body, fontName, "math", options,
["mop", "op-symbol", large ? "large-op" : "small-op"]);
} else if (group.value.value) {
// If this is a list, compose that list.
const inner = buildExpression(group.value.value, options, true);
if (inner.length === 1 && inner[0] instanceof domTree.symbolNode) {
base = inner[0];
base.classes[0] = "mop"; // replace old mclass
} else {
base = makeSpan(["mop"], inner, options);
}
} else {
// Otherwise, this is a text operator. Build the text from the
// operator's name.
// TODO(emily): Add a space in the middle of some of these
// operators, like \limsup
const output = [];
for (let i = 1; i < group.value.body.length; i++) {
output.push(buildCommon.mathsym(group.value.body[i], group.mode));
}
base = makeSpan(["mop"], output, options);
}
// If content of op is a single symbol, shift it vertically.
let baseShift = 0;
let slant = 0;
if (base instanceof domTree.symbolNode) {
// Shift the symbol so its center lies on the axis (rule 13). It
// appears that our fonts have the centers of the symbols already
// almost on the axis, so these numbers are very small. Note we
// don't actually apply this here, but instead it is used either in
// the vlist creation or separately when there are no limits.
baseShift = (base.height - base.depth) / 2 -
options.fontMetrics().axisHeight;
// The slant of the symbol is just its italic correction.
slant = base.italic;
}
if (hasLimits) {
// IE 8 clips \int if it is in a display: inline-block. We wrap it
// in a new span so it is an inline, and works.
base = makeSpan([], [base]);
let supm;
let supKern;
let subm;
let subKern;
let newOptions;
// We manually have to handle the superscripts and subscripts. This,
// aside from the kern calculations, is copied from supsub.
if (supGroup) {
newOptions = options.havingStyle(style.sup());
supm = buildGroup(supGroup, newOptions, options);
supKern = Math.max(
options.fontMetrics().bigOpSpacing1,
options.fontMetrics().bigOpSpacing3 - supm.depth);
}
if (subGroup) {
newOptions = options.havingStyle(style.sub());
subm = buildGroup(subGroup, newOptions, options);
subKern = Math.max(
options.fontMetrics().bigOpSpacing2,
options.fontMetrics().bigOpSpacing4 - subm.height);
}
// Build the final group as a vlist of the possible subscript, base,
// and possible superscript.
let finalGroup;
let top;
let bottom;
if (!supGroup) {
top = base.height - baseShift;
// Shift the limits by the slant of the symbol. Note
// that we are supposed to shift the limits by 1/2 of the slant,
// but since we are centering the limits adding a full slant of
// margin will shift by 1/2 that.
finalGroup = buildCommon.makeVList([
{type: "kern", size: options.fontMetrics().bigOpSpacing5},
{type: "elem", elem: subm, marginLeft: -slant + "em"},
{type: "kern", size: subKern},
{type: "elem", elem: base},
], "top", top, options);
} else if (!subGroup) {
bottom = base.depth + baseShift;
finalGroup = buildCommon.makeVList([
{type: "elem", elem: base},
{type: "kern", size: supKern},
{type: "elem", elem: supm, marginLeft: slant + "em"},
{type: "kern", size: options.fontMetrics().bigOpSpacing5},
], "bottom", bottom, options);
} else if (!supGroup && !subGroup) {
// This case probably shouldn't occur (this would mean the
// supsub was sending us a group with no superscript or
// subscript) but be safe.
return base;
} else {
bottom = options.fontMetrics().bigOpSpacing5 +
subm.height + subm.depth +
subKern +
base.depth + baseShift;
finalGroup = buildCommon.makeVList([
{type: "kern", size: options.fontMetrics().bigOpSpacing5},
{type: "elem", elem: subm, marginLeft: -slant + "em"},
{type: "kern", size: subKern},
{type: "elem", elem: base},
{type: "kern", size: supKern},
{type: "elem", elem: supm, marginLeft: slant + "em"},
{type: "kern", size: options.fontMetrics().bigOpSpacing5},
], "bottom", bottom, options);
}
return makeSpan(["mop", "op-limits"], [finalGroup], options);
} else {
if (baseShift) {
base.style.position = "relative";
base.style.top = baseShift + "em";
}
return base;
}
};
groupTypes.mod = function(group, options) {
const inner = [];
if (group.value.modType === "bmod") {
// “\nonscript\mskip-\medmuskip\mkern5mu”
if (!options.style.isTight()) {
inner.push(makeSpan(
["mspace", "negativemediumspace"], [], options));
}
inner.push(makeSpan(["mspace", "thickspace"], [], options));
} else if (options.style.size === Style.DISPLAY.size) {
inner.push(makeSpan(["mspace", "quad"], [], options));
} else if (group.value.modType === "mod") {
inner.push(makeSpan(["mspace", "twelvemuspace"], [], options));
} else {
inner.push(makeSpan(["mspace", "eightmuspace"], [], options));
}
if (group.value.modType === "pod" || group.value.modType === "pmod") {
inner.push(buildCommon.mathsym("(", group.mode));
}
if (group.value.modType !== "pod") {
const modInner = [
buildCommon.mathsym("m", group.mode),
buildCommon.mathsym("o", group.mode),
buildCommon.mathsym("d", group.mode)];
if (group.value.modType === "bmod") {
inner.push(makeSpan(["mbin"], modInner, options));
// “\mkern5mu\nonscript\mskip-\medmuskip”
inner.push(makeSpan(["mspace", "thickspace"], [], options));
if (!options.style.isTight()) {
inner.push(makeSpan(
["mspace", "negativemediumspace"], [], options));
}
} else {
Array.prototype.push.apply(inner, modInner);
inner.push(makeSpan(["mspace", "sixmuspace"], [], options));
}
}
if (group.value.value) {
Array.prototype.push.apply(inner,
buildExpression(group.value.value, options, false));
}
if (group.value.modType === "pod" || group.value.modType === "pmod") {
inner.push(buildCommon.mathsym(")", group.mode));
}
return buildCommon.makeFragment(inner);
};
groupTypes.katex = function(group, options) {
// The KaTeX logo. The offsets for the K and a were chosen to look
// good, but the offsets for the T, E, and X were taken from the
// definition of \TeX in TeX (see TeXbook pg. 356)
const k = makeSpan(
["k"], [buildCommon.mathsym("K", group.mode)], options);
const a = makeSpan(
["a"], [buildCommon.mathsym("A", group.mode)], options);
a.height = (a.height + 0.2) * 0.75;
a.depth = (a.height - 0.2) * 0.75;
const t = makeSpan(
["t"], [buildCommon.mathsym("T", group.mode)], options);
const e = makeSpan(
["e"], [buildCommon.mathsym("E", group.mode)], options);
e.height = (e.height - 0.2155);
e.depth = (e.depth + 0.2155);
const x = makeSpan(
["x"], [buildCommon.mathsym("X", group.mode)], options);
return makeSpan(
["mord", "katex-logo"], [k, a, t, e, x], options);
};
const makeLineSpan = function(className, options, thickness) {
const line = makeSpan([className], [], options);
line.height = thickness || options.fontMetrics().defaultRuleThickness;
line.style.borderBottomWidth = line.height + "em";
line.maxFontSize = 1.0;
return line;
};
groupTypes.overline = function(group, options) {
// Overlines are handled in the TeXbook pg 443, Rule 9.
// Build the inner group in the cramped style.
const innerGroup = buildGroup(group.value.body,
options.havingCrampedStyle());
// Create the line above the body
const line = makeLineSpan("overline-line", options);
// Generate the vlist, with the appropriate kerns
const vlist = buildCommon.makeVList([
{type: "elem", elem: innerGroup},
{type: "kern", size: 3 * line.height},
{type: "elem", elem: line},
{type: "kern", size: line.height},
], "firstBaseline", null, options);
return makeSpan(["mord", "overline"], [vlist], options);
};
groupTypes.underline = function(group, options) {
// Underlines are handled in the TeXbook pg 443, Rule 10.
// Build the inner group.
const innerGroup = buildGroup(group.value.body, options);
// Create the line above the body
const line = makeLineSpan("underline-line", options);
// Generate the vlist, with the appropriate kerns
const vlist = buildCommon.makeVList([
{type: "kern", size: line.height},
{type: "elem", elem: line},
{type: "kern", size: 3 * line.height},
{type: "elem", elem: innerGroup},
], "top", innerGroup.height, options);
return makeSpan(["mord", "underline"], [vlist], options);
};
groupTypes.sqrt = function(group, options) {
// Square roots are handled in the TeXbook pg. 443, Rule 11.
// First, we do the same steps as in overline to build the inner group
// and line
let inner = buildGroup(group.value.body, options.havingCrampedStyle());
// Some groups can return document fragments. Handle those by wrapping
// them in a span.
if (inner instanceof domTree.documentFragment) {
inner = makeSpan([], [inner], options);
}
// Calculate the minimum size for the \surd delimiter
const metrics = options.fontMetrics();
const theta = metrics.defaultRuleThickness;
let phi = theta;
if (options.style.id < Style.TEXT.id) {
phi = options.fontMetrics().xHeight;
}
// Calculate the clearance between the body and line
let lineClearance = theta + phi / 4;
const minDelimiterHeight = (inner.height + inner.depth +
lineClearance + theta) * options.sizeMultiplier;
// Create a sqrt SVG of the required minimum size
const img = delimiter.customSizedDelim("\\surd", minDelimiterHeight,
false, options, group.mode);
// Calculate the actual line width.
// This actually should depend on the chosen font -- e.g. \boldmath
// should use the thicker surd symbols from e.g. KaTeX_Main-Bold, and
// have thicker rules.
const ruleWidth = options.fontMetrics().sqrtRuleThickness *
img.sizeMultiplier;
const delimDepth = img.height - ruleWidth;
// Adjust the clearance based on the delimiter size
if (delimDepth > inner.height + inner.depth + lineClearance) {
lineClearance =
(lineClearance + delimDepth - inner.height - inner.depth) / 2;
}
// Shift the sqrt image
const imgShift = img.height - inner.height - lineClearance - ruleWidth;
// We add a special case here, because even when `inner` is empty, we
// still get a line. So, we use a simple heuristic to decide if we
// should omit the body entirely. (note this doesn't work for something
// like `\sqrt{\rlap{x}}`, but if someone is doing that they deserve for
// it not to work.
let body;
if (inner.height === 0 && inner.depth === 0) {
body = makeSpan();
} else {
inner.style.paddingLeft = img.surdWidth + "em";
// Overlay the image and the argument.
body = buildCommon.makeVList([
{type: "elem", elem: inner},
{type: "kern", size: -(inner.height + imgShift)},
{type: "elem", elem: img},
{type: "kern", size: ruleWidth},
], "firstBaseline", null, options);
body.children[0].children[0].classes.push("svg-align");
}
if (!group.value.index) {
return makeSpan(["mord", "sqrt"], [body], options);
} else {
// Handle the optional root index
// The index is always in scriptscript style
const newOptions = options.havingStyle(Style.SCRIPTSCRIPT);
const rootm = buildGroup(group.value.index, newOptions, options);
// The amount the index is shifted by. This is taken from the TeX
// source, in the definition of `\r@@t`.
const toShift = 0.6 * (body.height - body.depth);
// Build a VList with the superscript shifted up correctly
const rootVList = buildCommon.makeVList(
[{type: "elem", elem: rootm}],
"shift", -toShift, options);
// Add a class surrounding it so we can add on the appropriate
// kerning
const rootVListWrap = makeSpan(["root"], [rootVList]);
return makeSpan(["mord", "sqrt"],
[rootVListWrap, body], options);
}
};
function sizingGroup(value, options, baseOptions) {
const inner = buildExpression(value, options, false);
const multiplier = options.sizeMultiplier / baseOptions.sizeMultiplier;
// Add size-resetting classes to the inner list and set maxFontSize
// manually. Handle nested size changes.
for (let i = 0; i < inner.length; i++) {
const pos = utils.indexOf(inner[i].classes, "sizing");
if (pos < 0) {
Array.prototype.push.apply(inner[i].classes,
options.sizingClasses(baseOptions));
} else if (inner[i].classes[pos + 1] === "reset-size" + options.size) {
// This is a nested size change: e.g., inner[i] is the "b" in
// `\Huge a \small b`. Override the old size (the `reset-` class)
// but not the new size.
inner[i].classes[pos + 1] = "reset-size" + baseOptions.size;
}
inner[i].height *= multiplier;
inner[i].depth *= multiplier;
}
return buildCommon.makeFragment(inner);
}
groupTypes.sizing = function(group, options) {
// Handle sizing operators like \Huge. Real TeX doesn't actually allow
// these functions inside of math expressions, so we do some special
// handling.
const newOptions = options.havingSize(group.value.size);
return sizingGroup(group.value.value, newOptions, options);
};
groupTypes.styling = function(group, options) {
// Style changes are handled in the TeXbook on pg. 442, Rule 3.
// Figure out what style we're changing to.
const styleMap = {
"display": Style.DISPLAY,
"text": Style.TEXT,
"script": Style.SCRIPT,
"scriptscript": Style.SCRIPTSCRIPT,
};
const newStyle = styleMap[group.value.style];
const newOptions = options.havingStyle(newStyle);
return sizingGroup(group.value.value, newOptions, options);
};
groupTypes.font = function(group, options) {
const font = group.value.font;
return buildGroup(group.value.body, options.withFont(font));
};
groupTypes.delimsizing = function(group, options) {
const delim = group.value.value;
if (delim === ".") {
// Empty delimiters still count as elements, even though they don't
// show anything.
return makeSpan([group.value.mclass]);
}
// Use delimiter.sizedDelim to generate the delimiter.
return delimiter.sizedDelim(
delim, group.value.size, options, group.mode,
[group.value.mclass]);
};
groupTypes.leftright = function(group, options) {
// Build the inner expression
const inner = buildExpression(group.value.body, options, true);
let innerHeight = 0;
let innerDepth = 0;
let hadMiddle = false;
// Calculate its height and depth
for (let i = 0; i < inner.length; i++) {
if (inner[i].isMiddle) {
hadMiddle = true;
} else {
innerHeight = Math.max(inner[i].height, innerHeight);
innerDepth = Math.max(inner[i].depth, innerDepth);
}
}
// The size of delimiters is the same, regardless of what style we are
// in. Thus, to correctly calculate the size of delimiter we need around
// a group, we scale down the inner size based on the size.
innerHeight *= options.sizeMultiplier;
innerDepth *= options.sizeMultiplier;
let leftDelim;
if (group.value.left === ".") {
// Empty delimiters in \left and \right make null delimiter spaces.
leftDelim = makeNullDelimiter(options, ["mopen"]);
} else {
// Otherwise, use leftRightDelim to generate the correct sized
// delimiter.
leftDelim = delimiter.leftRightDelim(
group.value.left, innerHeight, innerDepth, options,
group.mode, ["mopen"]);
}
// Add it to the beginning of the expression
inner.unshift(leftDelim);
// Handle middle delimiters
if (hadMiddle) {
for (let i = 1; i < inner.length; i++) {
const middleDelim = inner[i];
if (middleDelim.isMiddle) {
// Apply the options that were active when \middle was called
inner[i] = delimiter.leftRightDelim(
middleDelim.isMiddle.value, innerHeight, innerDepth,
middleDelim.isMiddle.options, group.mode, []);
// Add back spaces shifted into the delimiter
const spaces = spliceSpaces(middleDelim.children, 0);
if (spaces) {
buildCommon.prependChildren(inner[i], spaces);
}
}
}
}
let rightDelim;
// Same for the right delimiter
if (group.value.right === ".") {
rightDelim = makeNullDelimiter(options, ["mclose"]);
} else {
rightDelim = delimiter.leftRightDelim(
group.value.right, innerHeight, innerDepth, options,
group.mode, ["mclose"]);
}
// Add it to the end of the expression.
inner.push(rightDelim);
return makeSpan(["minner"], inner, options);
};
groupTypes.middle = function(group, options) {
let middleDelim;
if (group.value.value === ".") {
middleDelim = makeNullDelimiter(options, []);
} else {
middleDelim = delimiter.sizedDelim(
group.value.value, 1, options,
group.mode, []);
middleDelim.isMiddle = {value: group.value.value, options: options};
}
return middleDelim;
};
groupTypes.rule = function(group, options) {
// Make an empty span for the rule
const rule = makeSpan(["mord", "rule"], [], options);
// Calculate the shift, width, and height of the rule, and account for units
let shift = 0;
if (group.value.shift) {
shift = units.calculateSize(group.value.shift, options);
}
const width = units.calculateSize(group.value.width, options);
const height = units.calculateSize(group.value.height, options);
// Style the rule to the right size
rule.style.borderRightWidth = width + "em";
rule.style.borderTopWidth = height + "em";
rule.style.bottom = shift + "em";
// Record the height and width
rule.width = width;
rule.height = height + shift;
rule.depth = -shift;
// Font size is the number large enough that the browser will
// reserve at least `absHeight` space above the baseline.
// The 1.125 factor was empirically determined
rule.maxFontSize = height * 1.125 * options.sizeMultiplier;
return rule;
};
groupTypes.kern = function(group, options) {
// Make an empty span for the rule
const rule = makeSpan(["mord", "rule"], [], options);
if (group.value.dimension) {
const dimension = units.calculateSize(group.value.dimension, options);
rule.style.marginLeft = dimension + "em";
}
return rule;
};
groupTypes.accent = function(group, options) {
// Accents are handled in the TeXbook pg. 443, rule 12.
let base = group.value.base;
let supsubGroup;
if (group.type === "supsub") {
// If our base is a character box, and we have superscripts and
// subscripts, the supsub will defer to us. In particular, we want
// to attach the superscripts and subscripts to the inner body (so
// that the position of the superscripts and subscripts won't be
// affected by the height of the accent). We accomplish this by
// sticking the base of the accent into the base of the supsub, and
// rendering that, while keeping track of where the accent is.
// The supsub group is the group that was passed in
const supsub = group;
// The real accent group is the base of the supsub group
group = supsub.value.base;
// The character box is the base of the accent group
base = group.value.base;
// Stick the character box into the base of the supsub group
supsub.value.base = base;
// Rerender the supsub group with its new base, and store that
// result.
supsubGroup = buildGroup(supsub, options);
}
// Build the base group
const body = buildGroup(base, options.havingCrampedStyle());
// Does the accent need to shift for the skew of a character?
const mustShift = group.value.isShifty && isCharacterBox(base);
// Calculate the skew of the accent. This is based on the line "If the
// nucleus is not a single character, let s = 0; otherwise set s to the
// kern amount for the nucleus followed by the \skewchar of its font."
// Note that our skew metrics are just the kern between each character
// and the skewchar.
let skew = 0;
if (mustShift) {
// If the base is a character box, then we want the skew of the
// innermost character. To do that, we find the innermost character:
const baseChar = getBaseElem(base);
// Then, we render its group to get the symbol inside it
const baseGroup = buildGroup(baseChar, options.havingCrampedStyle());
// Finally, we pull the skew off of the symbol.
skew = baseGroup.skew;
// Note that we now throw away baseGroup, because the layers we
// removed with getBaseElem might contain things like \color which
// we can't get rid of.
// TODO(emily): Find a better way to get the skew
}
// calculate the amount of space between the body and the accent
const clearance = Math.min(
body.height,
options.fontMetrics().xHeight);
// Build the accent
let accentBody;
if (!group.value.isStretchy) {
const accent = buildCommon.makeSymbol(
group.value.label, "Main-Regular", group.mode, options);
// Remove the italic correction of the accent, because it only serves to
// shift the accent over to a place we don't want.
accent.italic = 0;
// The \vec character that the fonts use is a combining character, and
// thus shows up much too far to the left. To account for this, we add a
// specific class which shifts the accent over to where we want it.
// TODO(emily): Fix this in a better way, like by changing the font
// Similarly, text accent \H is a combining character and
// requires a different adjustment.
let accentClass = null;
if (group.value.label === "\\vec") {
accentClass = "accent-vec";
} else if (group.value.label === '\\H') {
accentClass = "accent-hungarian";
}
accentBody = makeSpan([], [accent]);
accentBody = makeSpan(["accent-body", accentClass], [accentBody]);
// Shift the accent over by the skew. Note we shift by twice the skew
// because we are centering the accent, so by adding 2*skew to the left,
// we shift it to the right by 1*skew.
accentBody.style.marginLeft = 2 * skew + "em";
accentBody = buildCommon.makeVList([
{type: "elem", elem: body},
{type: "kern", size: -clearance},
{type: "elem", elem: accentBody},
], "firstBaseline", null, options);
} else {
accentBody = stretchy.svgSpan(group, options);
accentBody = buildCommon.makeVList([
{type: "elem", elem: body},
{type: "elem", elem: accentBody},
], "firstBaseline", null, options);
const styleSpan = accentBody.children[0].children[0].children[1];
styleSpan.classes.push("svg-align"); // text-align: left;
if (skew > 0) {
// Shorten the accent and nudge it to the right.
styleSpan.style.width = `calc(100% - ${2 * skew}em)`;
styleSpan.style.marginLeft = (2 * skew) + "em";
}
}
const accentWrap = makeSpan(["mord", "accent"], [accentBody], options);
if (supsubGroup) {
// Here, we replace the "base" child of the supsub with our newly
// generated accent.
supsubGroup.children[0] = accentWrap;
// Since we don't rerun the height calculation after replacing the
// accent, we manually recalculate height.
supsubGroup.height = Math.max(accentWrap.height, supsubGroup.height);
// Accents should always be ords, even when their innards are not.
supsubGroup.classes[0] = "mord";
return supsubGroup;
} else {
return accentWrap;
}
};
groupTypes.horizBrace = function(group, options) {
const style = options.style;
const hasSupSub = (group.type === "supsub");
let supSubGroup;
let newOptions;
if (hasSupSub) {
// Ref: LaTeX source2e: }}}}\limits}
// i.e. LaTeX treats the brace similar to an op and passes it
// with \limits, so we need to assign supsub style.
if (group.value.sup) {
newOptions = options.havingStyle(style.sup());
supSubGroup = buildGroup(group.value.sup, newOptions, options);
} else {
newOptions = options.havingStyle(style.sub());
supSubGroup = buildGroup(group.value.sub, newOptions, options);
}
group = group.value.base;
}
// Build the base group
const body = buildGroup(
group.value.base, options.havingBaseStyle(Style.DISPLAY));
// Create the stretchy element
const braceBody = stretchy.svgSpan(group, options);
// Generate the vlist, with the appropriate kerns ┏━━━━━━━━┓
// This first vlist contains the subject matter and the brace: equation
let vlist;
if (group.value.isOver) {
vlist = buildCommon.makeVList([
{type: "elem", elem: body},
{type: "kern", size: 0.1},
{type: "elem", elem: braceBody},
], "firstBaseline", null, options);
vlist.children[0].children[0].children[1].classes.push("svg-align");
} else {
vlist = buildCommon.makeVList([
{type: "elem", elem: braceBody},
{type: "kern", size: 0.1},
{type: "elem", elem: body},
], "bottom", body.depth + 0.1 + braceBody.height, options);
vlist.children[0].children[0].children[0].classes.push("svg-align");
}
if (hasSupSub) {
// In order to write the supsub, wrap the first vlist in another vlist:
// They can't all go in the same vlist, because the note might be wider
// than the equation. We want the equation to control the brace width.
// note long note long note
// ┏━━━━━━━━┓ or ┏━━━┓ not ┏━━━━━━━━━┓
// equation eqn eqn
const vSpan = makeSpan(["mord",
(group.value.isOver ? "mover" : "munder")],
[vlist], options);
if (group.value.isOver) {
vlist = buildCommon.makeVList([
{type: "elem", elem: vSpan},
{type: "kern", size: 0.2},
{type: "elem", elem: supSubGroup},
], "firstBaseline", null, options);
} else {
vlist = buildCommon.makeVList([
{type: "elem", elem: supSubGroup},
{type: "kern", size: 0.2},
{type: "elem", elem: vSpan},
], "bottom", vSpan.depth + 0.2 + supSubGroup.height,
options);
}
}
return makeSpan(["mord", (group.value.isOver ? "mover" : "munder")],
[vlist], options);
};
groupTypes.accentUnder = function(group, options) {
// Treat under accents much like underlines.
const innerGroup = buildGroup(group.value.body, options);
const accentBody = stretchy.svgSpan(group, options);
const kern = (/tilde/.test(group.value.label) ? 0.12 : 0);
// Generate the vlist, with the appropriate kerns
const vlist = buildCommon.makeVList([
{type: "elem", elem: accentBody},
{type: "kern", size: kern},
{type: "elem", elem: innerGroup},
], "bottom", accentBody.height + kern, options);
vlist.children[0].children[0].children[0].classes.push("svg-align");
return makeSpan(["mord", "accentunder"], [vlist], options);
};
groupTypes.enclose = function(group, options) {
// \cancel, \bcancel, \xcancel, \sout, \fbox
const inner = buildGroup(group.value.body, options);
const label = group.value.label.substr(1);
const scale = options.sizeMultiplier;
let img;
let pad = 0;
let imgShift = 0;
if (label === "sout") {
img = makeSpan(["stretchy", "sout"]);
img.height = options.fontMetrics().defaultRuleThickness / scale;
imgShift = -0.5 * options.fontMetrics().xHeight;
} else {
// Add horizontal padding
inner.classes.push((label === "fbox" ? "boxpad" : "cancel-pad"));
// Add vertical padding
const isCharBox = (isCharacterBox(group.value.body));
// ref: LaTeX source2e: \fboxsep = 3pt; \fboxrule = .4pt
// ref: cancel package: \advance\totalheight2\p@ % "+2"
pad = (label === "fbox" ? 0.34 : (isCharBox ? 0.2 : 0));
imgShift = inner.depth + pad;
img = stretchy.encloseSpan(inner, label, pad, options);
}
const vlist = buildCommon.makeVList([
{type: "elem", elem: inner, shift: 0},
{type: "elem", elem: img, shift: imgShift},
], "individualShift", null, options);
if (label !== "fbox") {
vlist.children[0].children[0].children[1].classes.push("svg-align");
}
if (/cancel/.test(label)) {
// cancel does not create horiz space for its line extension.
// That is, not when adjacent to a mord.
return makeSpan(["mord", "cancel-lap"], [vlist], options);
} else {
return makeSpan(["mord"], [vlist], options);
}
};
groupTypes.xArrow = function(group, options) {
const style = options.style;
// Build the argument groups in the appropriate style.
// Ref: amsmath.dtx: \hbox{$\scriptstyle\mkern#3mu{#6}\mkern#4mu$}%
let newOptions = options.havingStyle(style.sup());
const upperGroup = buildGroup(group.value.body, newOptions, options);
upperGroup.classes.push("x-arrow-pad");
let lowerGroup;
if (group.value.below) {
// Build the lower group
newOptions = options.havingStyle(style.sub());
lowerGroup = buildGroup(group.value.below, newOptions, options);
lowerGroup.classes.push("x-arrow-pad");
}
const arrowBody = stretchy.svgSpan(group, options);
const arrowShift = -options.fontMetrics().axisHeight + arrowBody.depth;
const upperShift = -options.fontMetrics().axisHeight - arrowBody.height -
0.111; // 2 mu. Ref: amsmath.dtx: #7\if0#2\else\mkern#2mu\fi
// Generate the vlist
let vlist;
if (group.value.below) {
const lowerShift = -options.fontMetrics().axisHeight
+ lowerGroup.height + arrowBody.height
+ 0.111;
vlist = buildCommon.makeVList([
{type: "elem", elem: upperGroup, shift: upperShift},
{type: "elem", elem: arrowBody, shift: arrowShift},
{type: "elem", elem: lowerGroup, shift: lowerShift},
], "individualShift", null, options);
} else {
vlist = buildCommon.makeVList([
{type: "elem", elem: upperGroup, shift: upperShift},
{type: "elem", elem: arrowBody, shift: arrowShift},
], "individualShift", null, options);
}
vlist.children[0].children[0].children[1].classes.push("svg-align");
return makeSpan(["mrel", "x-arrow"], [vlist], options);
};
groupTypes.phantom = function(group, options) {
const elements = buildExpression(
group.value.value,
options.withPhantom(),
false
);
// \phantom isn't supposed to affect the elements it contains.
// See "color" for more details.
return new buildCommon.makeFragment(elements);
};
groupTypes.mclass = function(group, options) {
const elements = buildExpression(group.value.value, options, true);
return makeSpan([group.value.mclass], elements, options);
};
/**
* buildGroup is the function that takes a group and calls the correct groupType
* function for it. It also handles the interaction of size and style changes
* between parents and children.
*/
const buildGroup = function(group, options, baseOptions) {
if (!group) {
return makeSpan();
}
if (groupTypes[group.type]) {
// Call the groupTypes function
let groupNode = groupTypes[group.type](group, options);
// If the size changed between the parent and the current group, account
// for that size difference.
if (baseOptions && options.size !== baseOptions.size) {
groupNode = makeSpan(options.sizingClasses(baseOptions),
[groupNode], options);
const multiplier = options.sizeMultiplier /
baseOptions.sizeMultiplier;
groupNode.height *= multiplier;
groupNode.depth *= multiplier;
}
return groupNode;
} else {
throw new ParseError(
"Got group of unknown type: '" + group.type + "'");
}
};
/**
* Take an entire parse tree, and build it into an appropriate set of HTML
* nodes.
*/
const buildHTML = function(tree, options) {
// buildExpression is destructive, so we need to make a clone
// of the incoming tree so that it isn't accidentally changed
tree = JSON.parse(JSON.stringify(tree));
// Build the expression contained in the tree
const expression = buildExpression(tree, options, true);
const body = makeSpan(["base"], expression, options);
// Add struts, which ensure that the top of the HTML element falls at the
// height of the expression, and the bottom of the HTML element falls at the
// depth of the expression.
const topStrut = makeSpan(["strut"]);
const bottomStrut = makeSpan(["strut", "bottom"]);
topStrut.style.height = body.height + "em";
bottomStrut.style.height = (body.height + body.depth) + "em";
// We'd like to use `vertical-align: top` but in IE 9 this lowers the
// baseline of the box to the bottom of this strut (instead staying in the
// normal place) so we use an absolute value for vertical-align instead
bottomStrut.style.verticalAlign = -body.depth + "em";
// Wrap the struts and body together
const htmlNode = makeSpan(["katex-html"], [topStrut, bottomStrut, body]);
htmlNode.setAttribute("aria-hidden", "true");
return htmlNode;
};
module.exports = buildHTML;