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836 lines
29 KiB
JavaScript
836 lines
29 KiB
JavaScript
// @flow
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/**
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* This file deals with creating delimiters of various sizes. The TeXbook
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* discusses these routines on page 441-442, in the "Another subroutine sets box
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* x to a specified variable delimiter" paragraph.
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*
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* There are three main routines here. `makeSmallDelim` makes a delimiter in the
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* normal font, but in either text, script, or scriptscript style.
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* `makeLargeDelim` makes a delimiter in textstyle, but in one of the Size1,
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* Size2, Size3, or Size4 fonts. `makeStackedDelim` makes a delimiter out of
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* smaller pieces that are stacked on top of one another.
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*
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* The functions take a parameter `center`, which determines if the delimiter
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* should be centered around the axis.
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*
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* Then, there are three exposed functions. `sizedDelim` makes a delimiter in
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* one of the given sizes. This is used for things like `\bigl`.
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* `customSizedDelim` makes a delimiter with a given total height+depth. It is
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* called in places like `\sqrt`. `leftRightDelim` makes an appropriate
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* delimiter which surrounds an expression of a given height an depth. It is
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* used in `\left` and `\right`.
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*/
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import ParseError from "./ParseError";
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import Style from "./Style";
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import {PathNode, SvgNode, SymbolNode} from "./domTree";
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import {sqrtPath, innerPath, tallDelim} from "./svgGeometry";
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import buildCommon from "./buildCommon";
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import {getCharacterMetrics} from "./fontMetrics";
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import symbols from "./symbols";
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import utils from "./utils";
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import {makeEm} from "./units";
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import fontMetricsData from "./fontMetricsData";
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import type Options from "./Options";
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import type {CharacterMetrics} from "./fontMetrics";
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import type {HtmlDomNode, DomSpan, SvgSpan} from "./domTree";
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import type {Mode} from "./types";
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import type {StyleInterface} from "./Style";
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import type {VListElem} from "./buildCommon";
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/**
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* Get the metrics for a given symbol and font, after transformation (i.e.
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* after following replacement from symbols.js)
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*/
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const getMetrics = function(
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symbol: string,
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font: string,
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mode: Mode,
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): CharacterMetrics {
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const replace = symbols.math[symbol] && symbols.math[symbol].replace;
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const metrics =
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getCharacterMetrics(replace || symbol, font, mode);
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if (!metrics) {
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throw new Error(`Unsupported symbol ${symbol} and font size ${font}.`);
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}
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return metrics;
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};
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/**
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* Puts a delimiter span in a given style, and adds appropriate height, depth,
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* and maxFontSizes.
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*/
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const styleWrap = function(
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delim: HtmlDomNode,
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toStyle: StyleInterface,
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options: Options,
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classes: string[],
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): DomSpan {
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const newOptions = options.havingBaseStyle(toStyle);
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const span = buildCommon.makeSpan(
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classes.concat(newOptions.sizingClasses(options)),
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[delim], options);
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const delimSizeMultiplier =
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newOptions.sizeMultiplier / options.sizeMultiplier;
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span.height *= delimSizeMultiplier;
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span.depth *= delimSizeMultiplier;
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span.maxFontSize = newOptions.sizeMultiplier;
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return span;
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};
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const centerSpan = function(
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span: DomSpan,
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options: Options,
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style: StyleInterface,
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) {
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const newOptions = options.havingBaseStyle(style);
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const shift =
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(1 - options.sizeMultiplier / newOptions.sizeMultiplier) *
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options.fontMetrics().axisHeight;
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span.classes.push("delimcenter");
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span.style.top = makeEm(shift);
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span.height -= shift;
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span.depth += shift;
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};
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/**
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* Makes a small delimiter. This is a delimiter that comes in the Main-Regular
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* font, but is restyled to either be in textstyle, scriptstyle, or
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* scriptscriptstyle.
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*/
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const makeSmallDelim = function(
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delim: string,
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style: StyleInterface,
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center: boolean,
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options: Options,
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mode: Mode,
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classes: string[],
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): DomSpan {
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const text = buildCommon.makeSymbol(delim, "Main-Regular", mode, options);
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const span = styleWrap(text, style, options, classes);
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if (center) {
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centerSpan(span, options, style);
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}
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return span;
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};
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/**
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* Builds a symbol in the given font size (note size is an integer)
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*/
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const mathrmSize = function(
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value: string,
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size: number,
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mode: Mode,
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options: Options,
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): SymbolNode {
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return buildCommon.makeSymbol(value, "Size" + size + "-Regular",
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mode, options);
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};
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/**
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* Makes a large delimiter. This is a delimiter that comes in the Size1, Size2,
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* Size3, or Size4 fonts. It is always rendered in textstyle.
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*/
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const makeLargeDelim = function(delim,
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size: number,
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center: boolean,
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options: Options,
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mode: Mode,
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classes: string[],
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): DomSpan {
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const inner = mathrmSize(delim, size, mode, options);
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const span = styleWrap(
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buildCommon.makeSpan(["delimsizing", "size" + size], [inner], options),
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Style.TEXT, options, classes);
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if (center) {
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centerSpan(span, options, Style.TEXT);
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}
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return span;
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};
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/**
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* Make a span from a font glyph with the given offset and in the given font.
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* This is used in makeStackedDelim to make the stacking pieces for the delimiter.
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*/
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const makeGlyphSpan = function(
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symbol: string,
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font: "Size1-Regular" | "Size4-Regular",
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mode: Mode,
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): VListElem {
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let sizeClass;
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// Apply the correct CSS class to choose the right font.
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if (font === "Size1-Regular") {
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sizeClass = "delim-size1";
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} else /* if (font === "Size4-Regular") */ {
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sizeClass = "delim-size4";
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}
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const corner = buildCommon.makeSpan(
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["delimsizinginner", sizeClass],
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[buildCommon.makeSpan([], [buildCommon.makeSymbol(symbol, font, mode)])]);
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// Since this will be passed into `makeVList` in the end, wrap the element
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// in the appropriate tag that VList uses.
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return {type: "elem", elem: corner};
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};
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const makeInner = function(
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ch: string,
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height: number,
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options: Options
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): VListElem {
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// Create a span with inline SVG for the inner part of a tall stacked delimiter.
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const width = fontMetricsData['Size4-Regular'][ch.charCodeAt(0)]
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? fontMetricsData['Size4-Regular'][ch.charCodeAt(0)][4]
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: fontMetricsData['Size1-Regular'][ch.charCodeAt(0)][4];
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const path = new PathNode("inner", innerPath(ch, Math.round(1000 * height)));
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const svgNode = new SvgNode([path], {
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"width": makeEm(width),
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"height": makeEm(height),
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// Override CSS rule `.katex svg { width: 100% }`
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"style": "width:" + makeEm(width),
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"viewBox": "0 0 " + 1000 * width + " " + Math.round(1000 * height),
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"preserveAspectRatio": "xMinYMin",
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});
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const span = buildCommon.makeSvgSpan([], [svgNode], options);
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span.height = height;
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span.style.height = makeEm(height);
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span.style.width = makeEm(width);
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return {type: "elem", elem: span};
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};
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// Helpers for makeStackedDelim
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const lapInEms = 0.008;
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const lap = {type: "kern", size: -1 * lapInEms};
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const verts = ["|", "\\lvert", "\\rvert", "\\vert"];
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const doubleVerts = ["\\|", "\\lVert", "\\rVert", "\\Vert"];
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/**
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* Make a stacked delimiter out of a given delimiter, with the total height at
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* least `heightTotal`. This routine is mentioned on page 442 of the TeXbook.
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*/
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const makeStackedDelim = function(
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delim: string,
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heightTotal: number,
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center: boolean,
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options: Options,
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mode: Mode,
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classes: string[],
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): DomSpan {
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// There are four parts, the top, an optional middle, a repeated part, and a
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// bottom.
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let top;
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let middle;
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let repeat;
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let bottom;
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let svgLabel = "";
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let viewBoxWidth = 0;
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top = repeat = bottom = delim;
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middle = null;
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// Also keep track of what font the delimiters are in
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let font = "Size1-Regular";
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// We set the parts and font based on the symbol. Note that we use
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// '\u23d0' instead of '|' and '\u2016' instead of '\\|' for the
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// repeats of the arrows
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if (delim === "\\uparrow") {
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repeat = bottom = "\u23d0";
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} else if (delim === "\\Uparrow") {
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repeat = bottom = "\u2016";
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} else if (delim === "\\downarrow") {
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top = repeat = "\u23d0";
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} else if (delim === "\\Downarrow") {
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top = repeat = "\u2016";
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} else if (delim === "\\updownarrow") {
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top = "\\uparrow";
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repeat = "\u23d0";
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bottom = "\\downarrow";
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} else if (delim === "\\Updownarrow") {
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top = "\\Uparrow";
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repeat = "\u2016";
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bottom = "\\Downarrow";
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} else if (utils.contains(verts, delim)) {
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repeat = "\u2223";
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svgLabel = "vert";
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viewBoxWidth = 333;
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} else if (utils.contains(doubleVerts, delim)) {
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repeat = "\u2225";
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svgLabel = "doublevert";
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viewBoxWidth = 556;
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} else if (delim === "[" || delim === "\\lbrack") {
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top = "\u23a1";
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repeat = "\u23a2";
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bottom = "\u23a3";
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font = "Size4-Regular";
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svgLabel = "lbrack";
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viewBoxWidth = 667;
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} else if (delim === "]" || delim === "\\rbrack") {
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top = "\u23a4";
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repeat = "\u23a5";
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bottom = "\u23a6";
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font = "Size4-Regular";
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svgLabel = "rbrack";
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viewBoxWidth = 667;
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} else if (delim === "\\lfloor" || delim === "\u230a") {
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repeat = top = "\u23a2";
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bottom = "\u23a3";
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font = "Size4-Regular";
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svgLabel = "lfloor";
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viewBoxWidth = 667;
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} else if (delim === "\\lceil" || delim === "\u2308") {
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top = "\u23a1";
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repeat = bottom = "\u23a2";
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font = "Size4-Regular";
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svgLabel = "lceil";
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viewBoxWidth = 667;
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} else if (delim === "\\rfloor" || delim === "\u230b") {
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repeat = top = "\u23a5";
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bottom = "\u23a6";
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font = "Size4-Regular";
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svgLabel = "rfloor";
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viewBoxWidth = 667;
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} else if (delim === "\\rceil" || delim === "\u2309") {
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top = "\u23a4";
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repeat = bottom = "\u23a5";
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font = "Size4-Regular";
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svgLabel = "rceil";
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viewBoxWidth = 667;
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} else if (delim === "(" || delim === "\\lparen") {
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top = "\u239b";
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repeat = "\u239c";
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bottom = "\u239d";
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font = "Size4-Regular";
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svgLabel = "lparen";
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viewBoxWidth = 875;
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} else if (delim === ")" || delim === "\\rparen") {
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top = "\u239e";
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repeat = "\u239f";
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bottom = "\u23a0";
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font = "Size4-Regular";
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svgLabel = "rparen";
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viewBoxWidth = 875;
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} else if (delim === "\\{" || delim === "\\lbrace") {
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top = "\u23a7";
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middle = "\u23a8";
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bottom = "\u23a9";
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repeat = "\u23aa";
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font = "Size4-Regular";
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} else if (delim === "\\}" || delim === "\\rbrace") {
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top = "\u23ab";
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middle = "\u23ac";
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bottom = "\u23ad";
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repeat = "\u23aa";
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font = "Size4-Regular";
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} else if (delim === "\\lgroup" || delim === "\u27ee") {
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top = "\u23a7";
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bottom = "\u23a9";
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repeat = "\u23aa";
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font = "Size4-Regular";
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} else if (delim === "\\rgroup" || delim === "\u27ef") {
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top = "\u23ab";
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bottom = "\u23ad";
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repeat = "\u23aa";
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font = "Size4-Regular";
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} else if (delim === "\\lmoustache" || delim === "\u23b0") {
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top = "\u23a7";
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bottom = "\u23ad";
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repeat = "\u23aa";
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font = "Size4-Regular";
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} else if (delim === "\\rmoustache" || delim === "\u23b1") {
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top = "\u23ab";
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bottom = "\u23a9";
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repeat = "\u23aa";
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font = "Size4-Regular";
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}
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// Get the metrics of the four sections
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const topMetrics = getMetrics(top, font, mode);
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const topHeightTotal = topMetrics.height + topMetrics.depth;
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const repeatMetrics = getMetrics(repeat, font, mode);
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const repeatHeightTotal = repeatMetrics.height + repeatMetrics.depth;
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const bottomMetrics = getMetrics(bottom, font, mode);
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const bottomHeightTotal = bottomMetrics.height + bottomMetrics.depth;
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let middleHeightTotal = 0;
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let middleFactor = 1;
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if (middle !== null) {
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const middleMetrics = getMetrics(middle, font, mode);
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middleHeightTotal = middleMetrics.height + middleMetrics.depth;
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middleFactor = 2; // repeat symmetrically above and below middle
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}
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// Calculate the minimal height that the delimiter can have.
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// It is at least the size of the top, bottom, and optional middle combined.
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const minHeight = topHeightTotal + bottomHeightTotal + middleHeightTotal;
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// Compute the number of copies of the repeat symbol we will need
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const repeatCount = Math.max(0, Math.ceil(
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(heightTotal - minHeight) / (middleFactor * repeatHeightTotal)));
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// Compute the total height of the delimiter including all the symbols
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const realHeightTotal =
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minHeight + repeatCount * middleFactor * repeatHeightTotal;
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// The center of the delimiter is placed at the center of the axis. Note
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// that in this context, "center" means that the delimiter should be
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// centered around the axis in the current style, while normally it is
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// centered around the axis in textstyle.
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let axisHeight = options.fontMetrics().axisHeight;
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if (center) {
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axisHeight *= options.sizeMultiplier;
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}
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// Calculate the depth
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const depth = realHeightTotal / 2 - axisHeight;
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// Now, we start building the pieces that will go into the vlist
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// Keep a list of the pieces of the stacked delimiter
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const stack = [];
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if (svgLabel.length > 0) {
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// Instead of stacking glyphs, create a single SVG.
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// This evades browser problems with imprecise positioning of spans.
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const midHeight = realHeightTotal - topHeightTotal - bottomHeightTotal;
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const viewBoxHeight = Math.round(realHeightTotal * 1000);
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const pathStr = tallDelim(svgLabel, Math.round(midHeight * 1000));
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const path = new PathNode(svgLabel, pathStr);
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const width = (viewBoxWidth / 1000).toFixed(3) + "em";
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const height = (viewBoxHeight / 1000).toFixed(3) + "em";
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const svg = new SvgNode([path], {
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"width": width,
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"height": height,
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"viewBox": `0 0 ${viewBoxWidth} ${viewBoxHeight}`,
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});
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const wrapper = buildCommon.makeSvgSpan([], [svg], options);
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wrapper.height = viewBoxHeight / 1000;
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wrapper.style.width = width;
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wrapper.style.height = height;
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stack.push({type: "elem", elem: wrapper});
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} else {
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// Stack glyphs
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// Start by adding the bottom symbol
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stack.push(makeGlyphSpan(bottom, font, mode));
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stack.push(lap); // overlap
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if (middle === null) {
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// The middle section will be an SVG. Make it an extra 0.016em tall.
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// We'll overlap by 0.008em at top and bottom.
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const innerHeight = realHeightTotal - topHeightTotal - bottomHeightTotal
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+ 2 * lapInEms;
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stack.push(makeInner(repeat, innerHeight, options));
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} else {
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// When there is a middle bit, we need the middle part and two repeated
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// sections
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const innerHeight = (realHeightTotal - topHeightTotal -
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bottomHeightTotal - middleHeightTotal) / 2 + 2 * lapInEms;
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stack.push(makeInner(repeat, innerHeight, options));
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// Now insert the middle of the brace.
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stack.push(lap);
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stack.push(makeGlyphSpan(middle, font, mode));
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stack.push(lap);
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stack.push(makeInner(repeat, innerHeight, options));
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}
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// Add the top symbol
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stack.push(lap);
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stack.push(makeGlyphSpan(top, font, mode));
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}
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// Finally, build the vlist
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const newOptions = options.havingBaseStyle(Style.TEXT);
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const inner = buildCommon.makeVList({
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positionType: "bottom",
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positionData: depth,
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children: stack,
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}, newOptions);
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return styleWrap(
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buildCommon.makeSpan(["delimsizing", "mult"], [inner], newOptions),
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Style.TEXT, options, classes);
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};
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// All surds have 0.08em padding above the vinculum inside the SVG.
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// That keeps browser span height rounding error from pinching the line.
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const vbPad = 80; // padding above the surd, measured inside the viewBox.
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const emPad = 0.08; // padding, in ems, measured in the document.
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const sqrtSvg = function(
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sqrtName: string,
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height: number,
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viewBoxHeight: number,
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extraVinculum: number,
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options: Options,
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): SvgSpan {
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const path = sqrtPath(sqrtName, extraVinculum, viewBoxHeight);
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const pathNode = new PathNode(sqrtName, path);
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const svg = new SvgNode([pathNode], {
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// Note: 1000:1 ratio of viewBox to document em width.
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"width": "400em",
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"height": makeEm(height),
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"viewBox": "0 0 400000 " + viewBoxHeight,
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"preserveAspectRatio": "xMinYMin slice",
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});
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return buildCommon.makeSvgSpan(["hide-tail"], [svg], options);
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};
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|
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/**
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|
* Make a sqrt image of the given height,
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*/
|
|
const makeSqrtImage = function(
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height: number,
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options: Options,
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|
): {
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span: SvgSpan,
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ruleWidth: number,
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|
advanceWidth: number,
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|
} {
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// Define a newOptions that removes the effect of size changes such as \Huge.
|
|
// We don't pick different a height surd for \Huge. For it, we scale up.
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|
const newOptions = options.havingBaseSizing();
|
|
|
|
// Pick the desired surd glyph from a sequence of surds.
|
|
const delim = traverseSequence("\\surd", height * newOptions.sizeMultiplier,
|
|
stackLargeDelimiterSequence, newOptions);
|
|
|
|
let sizeMultiplier = newOptions.sizeMultiplier; // default
|
|
|
|
// The standard sqrt SVGs each have a 0.04em thick vinculum.
|
|
// If Settings.minRuleThickness is larger than that, we add extraVinculum.
|
|
const extraVinculum = Math.max(0,
|
|
options.minRuleThickness - options.fontMetrics().sqrtRuleThickness);
|
|
|
|
// Create a span containing an SVG image of a sqrt symbol.
|
|
let span;
|
|
let spanHeight = 0;
|
|
let texHeight = 0;
|
|
let viewBoxHeight = 0;
|
|
let advanceWidth;
|
|
|
|
// We create viewBoxes with 80 units of "padding" above each surd.
|
|
// Then browser rounding error on the parent span height will not
|
|
// encroach on the ink of the vinculum. But that padding is not
|
|
// included in the TeX-like `height` used for calculation of
|
|
// vertical alignment. So texHeight = span.height < span.style.height.
|
|
|
|
if (delim.type === "small") {
|
|
// Get an SVG that is derived from glyph U+221A in font KaTeX-Main.
|
|
// 1000 unit normal glyph height.
|
|
viewBoxHeight = 1000 + 1000 * extraVinculum + vbPad;
|
|
if (height < 1.0) {
|
|
sizeMultiplier = 1.0; // mimic a \textfont radical
|
|
} else if (height < 1.4) {
|
|
sizeMultiplier = 0.7; // mimic a \scriptfont radical
|
|
}
|
|
spanHeight = (1.0 + extraVinculum + emPad) / sizeMultiplier;
|
|
texHeight = (1.00 + extraVinculum) / sizeMultiplier;
|
|
span = sqrtSvg("sqrtMain", spanHeight, viewBoxHeight, extraVinculum,
|
|
options);
|
|
span.style.minWidth = "0.853em";
|
|
advanceWidth = 0.833 / sizeMultiplier; // from the font.
|
|
|
|
} else if (delim.type === "large") {
|
|
// These SVGs come from fonts: KaTeX_Size1, _Size2, etc.
|
|
viewBoxHeight = (1000 + vbPad) * sizeToMaxHeight[delim.size];
|
|
texHeight = (sizeToMaxHeight[delim.size] + extraVinculum) / sizeMultiplier;
|
|
spanHeight = (sizeToMaxHeight[delim.size] + extraVinculum + emPad)
|
|
/ sizeMultiplier;
|
|
span = sqrtSvg("sqrtSize" + delim.size, spanHeight, viewBoxHeight,
|
|
extraVinculum, options);
|
|
span.style.minWidth = "1.02em";
|
|
advanceWidth = 1.0 / sizeMultiplier; // 1.0 from the font.
|
|
|
|
} else {
|
|
// Tall sqrt. In TeX, this would be stacked using multiple glyphs.
|
|
// We'll use a single SVG to accomplish the same thing.
|
|
spanHeight = height + extraVinculum + emPad;
|
|
texHeight = height + extraVinculum;
|
|
viewBoxHeight = Math.floor(1000 * height + extraVinculum) + vbPad;
|
|
span = sqrtSvg("sqrtTall", spanHeight, viewBoxHeight, extraVinculum,
|
|
options);
|
|
span.style.minWidth = "0.742em";
|
|
advanceWidth = 1.056;
|
|
}
|
|
|
|
span.height = texHeight;
|
|
span.style.height = makeEm(spanHeight);
|
|
|
|
return {
|
|
span,
|
|
advanceWidth,
|
|
// 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.
|
|
ruleWidth: (options.fontMetrics().sqrtRuleThickness + extraVinculum)
|
|
* sizeMultiplier,
|
|
};
|
|
};
|
|
|
|
// There are three kinds of delimiters, delimiters that stack when they become
|
|
// too large
|
|
const stackLargeDelimiters = [
|
|
"(", "\\lparen", ")", "\\rparen",
|
|
"[", "\\lbrack", "]", "\\rbrack",
|
|
"\\{", "\\lbrace", "\\}", "\\rbrace",
|
|
"\\lfloor", "\\rfloor", "\u230a", "\u230b",
|
|
"\\lceil", "\\rceil", "\u2308", "\u2309",
|
|
"\\surd",
|
|
];
|
|
|
|
// delimiters that always stack
|
|
const stackAlwaysDelimiters = [
|
|
"\\uparrow", "\\downarrow", "\\updownarrow",
|
|
"\\Uparrow", "\\Downarrow", "\\Updownarrow",
|
|
"|", "\\|", "\\vert", "\\Vert",
|
|
"\\lvert", "\\rvert", "\\lVert", "\\rVert",
|
|
"\\lgroup", "\\rgroup", "\u27ee", "\u27ef",
|
|
"\\lmoustache", "\\rmoustache", "\u23b0", "\u23b1",
|
|
];
|
|
|
|
// and delimiters that never stack
|
|
const stackNeverDelimiters = [
|
|
"<", ">", "\\langle", "\\rangle", "/", "\\backslash", "\\lt", "\\gt",
|
|
];
|
|
|
|
// Metrics of the different sizes. Found by looking at TeX's output of
|
|
// $\bigl| // \Bigl| \biggl| \Biggl| \showlists$
|
|
// Used to create stacked delimiters of appropriate sizes in makeSizedDelim.
|
|
const sizeToMaxHeight = [0, 1.2, 1.8, 2.4, 3.0];
|
|
|
|
/**
|
|
* Used to create a delimiter of a specific size, where `size` is 1, 2, 3, or 4.
|
|
*/
|
|
const makeSizedDelim = function(
|
|
delim: string,
|
|
size: number,
|
|
options: Options,
|
|
mode: Mode,
|
|
classes: string[],
|
|
): DomSpan {
|
|
// < and > turn into \langle and \rangle in delimiters
|
|
if (delim === "<" || delim === "\\lt" || delim === "\u27e8") {
|
|
delim = "\\langle";
|
|
} else if (delim === ">" || delim === "\\gt" || delim === "\u27e9") {
|
|
delim = "\\rangle";
|
|
}
|
|
|
|
// Sized delimiters are never centered.
|
|
if (utils.contains(stackLargeDelimiters, delim) ||
|
|
utils.contains(stackNeverDelimiters, delim)) {
|
|
return makeLargeDelim(delim, size, false, options, mode, classes);
|
|
} else if (utils.contains(stackAlwaysDelimiters, delim)) {
|
|
return makeStackedDelim(
|
|
delim, sizeToMaxHeight[size], false, options, mode, classes);
|
|
} else {
|
|
throw new ParseError("Illegal delimiter: '" + delim + "'");
|
|
}
|
|
};
|
|
|
|
/**
|
|
* There are three different sequences of delimiter sizes that the delimiters
|
|
* follow depending on the kind of delimiter. This is used when creating custom
|
|
* sized delimiters to decide whether to create a small, large, or stacked
|
|
* delimiter.
|
|
*
|
|
* In real TeX, these sequences aren't explicitly defined, but are instead
|
|
* defined inside the font metrics. Since there are only three sequences that
|
|
* are possible for the delimiters that TeX defines, it is easier to just encode
|
|
* them explicitly here.
|
|
*/
|
|
|
|
type Delimiter =
|
|
{type: "small", style: StyleInterface} |
|
|
{type: "large", size: 1 | 2 | 3 | 4} |
|
|
{type: "stack"};
|
|
|
|
// Delimiters that never stack try small delimiters and large delimiters only
|
|
const stackNeverDelimiterSequence = [
|
|
{type: "small", style: Style.SCRIPTSCRIPT},
|
|
{type: "small", style: Style.SCRIPT},
|
|
{type: "small", style: Style.TEXT},
|
|
{type: "large", size: 1},
|
|
{type: "large", size: 2},
|
|
{type: "large", size: 3},
|
|
{type: "large", size: 4},
|
|
];
|
|
|
|
// Delimiters that always stack try the small delimiters first, then stack
|
|
const stackAlwaysDelimiterSequence = [
|
|
{type: "small", style: Style.SCRIPTSCRIPT},
|
|
{type: "small", style: Style.SCRIPT},
|
|
{type: "small", style: Style.TEXT},
|
|
{type: "stack"},
|
|
];
|
|
|
|
// Delimiters that stack when large try the small and then large delimiters, and
|
|
// stack afterwards
|
|
const stackLargeDelimiterSequence = [
|
|
{type: "small", style: Style.SCRIPTSCRIPT},
|
|
{type: "small", style: Style.SCRIPT},
|
|
{type: "small", style: Style.TEXT},
|
|
{type: "large", size: 1},
|
|
{type: "large", size: 2},
|
|
{type: "large", size: 3},
|
|
{type: "large", size: 4},
|
|
{type: "stack"},
|
|
];
|
|
|
|
/**
|
|
* Get the font used in a delimiter based on what kind of delimiter it is.
|
|
* TODO(#963) Use more specific font family return type once that is introduced.
|
|
*/
|
|
const delimTypeToFont = function(type: Delimiter): string {
|
|
if (type.type === "small") {
|
|
return "Main-Regular";
|
|
} else if (type.type === "large") {
|
|
return "Size" + type.size + "-Regular";
|
|
} else if (type.type === "stack") {
|
|
return "Size4-Regular";
|
|
} else {
|
|
throw new Error(`Add support for delim type '${type.type}' here.`);
|
|
}
|
|
};
|
|
|
|
/**
|
|
* Traverse a sequence of types of delimiters to decide what kind of delimiter
|
|
* should be used to create a delimiter of the given height+depth.
|
|
*/
|
|
const traverseSequence = function(
|
|
delim: string,
|
|
height: number,
|
|
sequence: Delimiter[],
|
|
options: Options,
|
|
): Delimiter {
|
|
// Here, we choose the index we should start at in the sequences. In smaller
|
|
// sizes (which correspond to larger numbers in style.size) we start earlier
|
|
// in the sequence. Thus, scriptscript starts at index 3-3=0, script starts
|
|
// at index 3-2=1, text starts at 3-1=2, and display starts at min(2,3-0)=2
|
|
const start = Math.min(2, 3 - options.style.size);
|
|
for (let i = start; i < sequence.length; i++) {
|
|
if (sequence[i].type === "stack") {
|
|
// This is always the last delimiter, so we just break the loop now.
|
|
break;
|
|
}
|
|
|
|
const metrics = getMetrics(delim, delimTypeToFont(sequence[i]), "math");
|
|
let heightDepth = metrics.height + metrics.depth;
|
|
|
|
// Small delimiters are scaled down versions of the same font, so we
|
|
// account for the style change size.
|
|
|
|
if (sequence[i].type === "small") {
|
|
const newOptions = options.havingBaseStyle(sequence[i].style);
|
|
heightDepth *= newOptions.sizeMultiplier;
|
|
}
|
|
|
|
// Check if the delimiter at this size works for the given height.
|
|
if (heightDepth > height) {
|
|
return sequence[i];
|
|
}
|
|
}
|
|
|
|
// If we reached the end of the sequence, return the last sequence element.
|
|
return sequence[sequence.length - 1];
|
|
};
|
|
|
|
/**
|
|
* Make a delimiter of a given height+depth, with optional centering. Here, we
|
|
* traverse the sequences, and create a delimiter that the sequence tells us to.
|
|
*/
|
|
const makeCustomSizedDelim = function(
|
|
delim: string,
|
|
height: number,
|
|
center: boolean,
|
|
options: Options,
|
|
mode: Mode,
|
|
classes: string[],
|
|
): DomSpan {
|
|
if (delim === "<" || delim === "\\lt" || delim === "\u27e8") {
|
|
delim = "\\langle";
|
|
} else if (delim === ">" || delim === "\\gt" || delim === "\u27e9") {
|
|
delim = "\\rangle";
|
|
}
|
|
|
|
// Decide what sequence to use
|
|
let sequence;
|
|
if (utils.contains(stackNeverDelimiters, delim)) {
|
|
sequence = stackNeverDelimiterSequence;
|
|
} else if (utils.contains(stackLargeDelimiters, delim)) {
|
|
sequence = stackLargeDelimiterSequence;
|
|
} else {
|
|
sequence = stackAlwaysDelimiterSequence;
|
|
}
|
|
|
|
// Look through the sequence
|
|
const delimType = traverseSequence(delim, height, sequence, options);
|
|
|
|
// Get the delimiter from font glyphs.
|
|
// Depending on the sequence element we decided on, call the
|
|
// appropriate function.
|
|
if (delimType.type === "small") {
|
|
return makeSmallDelim(delim, delimType.style, center, options,
|
|
mode, classes);
|
|
} else if (delimType.type === "large") {
|
|
return makeLargeDelim(delim, delimType.size, center, options, mode,
|
|
classes);
|
|
} else /* if (delimType.type === "stack") */ {
|
|
return makeStackedDelim(delim, height, center, options, mode,
|
|
classes);
|
|
}
|
|
};
|
|
|
|
/**
|
|
* Make a delimiter for use with `\left` and `\right`, given a height and depth
|
|
* of an expression that the delimiters surround.
|
|
*/
|
|
const makeLeftRightDelim = function(
|
|
delim: string,
|
|
height: number,
|
|
depth: number,
|
|
options: Options,
|
|
mode: Mode,
|
|
classes: string[],
|
|
): DomSpan {
|
|
// We always center \left/\right delimiters, so the axis is always shifted
|
|
const axisHeight =
|
|
options.fontMetrics().axisHeight * options.sizeMultiplier;
|
|
|
|
// Taken from TeX source, tex.web, function make_left_right
|
|
const delimiterFactor = 901;
|
|
const delimiterExtend = 5.0 / options.fontMetrics().ptPerEm;
|
|
|
|
const maxDistFromAxis = Math.max(
|
|
height - axisHeight, depth + axisHeight);
|
|
|
|
const totalHeight = Math.max(
|
|
// In real TeX, calculations are done using integral values which are
|
|
// 65536 per pt, or 655360 per em. So, the division here truncates in
|
|
// TeX but doesn't here, producing different results. If we wanted to
|
|
// exactly match TeX's calculation, we could do
|
|
// Math.floor(655360 * maxDistFromAxis / 500) *
|
|
// delimiterFactor / 655360
|
|
// (To see the difference, compare
|
|
// x^{x^{\left(\rule{0.1em}{0.68em}\right)}}
|
|
// in TeX and KaTeX)
|
|
maxDistFromAxis / 500 * delimiterFactor,
|
|
2 * maxDistFromAxis - delimiterExtend);
|
|
|
|
// Finally, we defer to `makeCustomSizedDelim` with our calculated total
|
|
// height
|
|
return makeCustomSizedDelim(delim, totalHeight, true, options, mode, classes);
|
|
};
|
|
|
|
export default {
|
|
sqrtImage: makeSqrtImage,
|
|
sizedDelim: makeSizedDelim,
|
|
sizeToMaxHeight: sizeToMaxHeight,
|
|
customSizedDelim: makeCustomSizedDelim,
|
|
leftRightDelim: makeLeftRightDelim,
|
|
};
|