fix: round dimensions to 4 places (#2460)

* Round distances to 4 places

* Revert numbers in mathMLTree.js

* Update Jest test

* fix: round dimension to 4 places via makeEm

* test: update screenshots

* docs: add link to this PR

Co-authored-by: ylemkimon <y@ylem.kim>

src/buildCommon.js

@@ -9,7 +9,7 @@ import {SymbolNode, Anchor, Span, PathNode, SvgNode, createClass} from "./domTre
 import {getCharacterMetrics} from "./fontMetrics";
 import symbols, {ligatures} from "./symbols";
 import {wideCharacterFont} from "./wide-character";
-import {calculateSize} from "./units";
+import {calculateSize, makeEm} from "./units";
 import {DocumentFragment} from "./tree";
 
 import type Options from "./Options";
@@ -364,7 +364,7 @@ const makeLineSpan = function(
         thickness || options.fontMetrics().defaultRuleThickness,
         options.minRuleThickness,
     );
-    line.style.borderBottomWidth = line.height + "em";
+    line.style.borderBottomWidth = makeEm(line.height);
     line.maxFontSize = 1.0;
     return line;
 };
@@ -550,7 +550,7 @@ const makeVList = function(params: VListParam, options: Options): DomSpan {
     }
     pstrutSize += 2;
     const pstrut = makeSpan(["pstrut"], []);
-    pstrut.style.height = pstrutSize + "em";
+    pstrut.style.height = makeEm(pstrutSize);
 
     // Create a new list of actual children at the correct offsets
     const realChildren = [];
@@ -567,7 +567,7 @@ const makeVList = function(params: VListParam, options: Options): DomSpan {
             const style = child.wrapperStyle || {};
 
             const childWrap = makeSpan(classes, [pstrut, elem], undefined, style);
-            childWrap.style.top = (-pstrutSize - currPos - elem.depth) + "em";
+            childWrap.style.top = makeEm(-pstrutSize - currPos - elem.depth);
             if (child.marginLeft) {
                 childWrap.style.marginLeft = child.marginLeft;
             }
@@ -586,7 +586,7 @@ const makeVList = function(params: VListParam, options: Options): DomSpan {
     // This cell's bottom edge will determine the containing table's baseline
     // without overly expanding the containing line-box.
     const vlist = makeSpan(["vlist"], realChildren);
-    vlist.style.height = maxPos + "em";
+    vlist.style.height = makeEm(maxPos);
 
     // A second row is used if necessary to represent the vlist's depth.
     let rows;
@@ -598,7 +598,7 @@ const makeVList = function(params: VListParam, options: Options): DomSpan {
         // So we put another empty span inside the depth strut span.
         const emptySpan = makeSpan([], []);
         const depthStrut = makeSpan(["vlist"], [emptySpan]);
-        depthStrut.style.height = -minPos + "em";
+        depthStrut.style.height = makeEm(-minPos);
 
         // Safari wants the first row to have inline content; otherwise it
         // puts the bottom of the *second* row on the baseline.
@@ -626,7 +626,7 @@ const makeGlue = (measurement: Measurement, options: Options): DomSpan => {
     // Make an empty span for the space
     const rule = makeSpan(["mspace"], [], options);
     const size = calculateSize(measurement, options);
-    rule.style.marginRight = `${size}em`;
+    rule.style.marginRight = makeEm(size);
     return rule;
 };
 
@@ -744,17 +744,17 @@ const staticSvg = function(value: string, options: Options): SvgSpan {
     const [pathName, width, height] = svgData[value];
     const path = new PathNode(pathName);
     const svgNode = new SvgNode([path], {
-        "width": width + "em",
-        "height": height + "em",
+        "width": makeEm(width),
+        "height": makeEm(height),
         // Override CSS rule `.katex svg { width: 100% }`
-        "style": "width:" + width + "em",
+        "style": "width:" + makeEm(width),
         "viewBox": "0 0 " + 1000 * width + " " + 1000 * height,
         "preserveAspectRatio": "xMinYMin",
     });
     const span = makeSvgSpan(["overlay"], [svgNode], options);
     span.height = height;
-    span.style.height = height + "em";
-    span.style.width = width + "em";
+    span.style.height = makeEm(height);
+    span.style.width = makeEm(width);
     return span;
 };
 

src/buildHTML.js

@@ -11,6 +11,7 @@ import Style from "./Style";
 import buildCommon from "./buildCommon";
 import {Span, Anchor} from "./domTree";
 import utils from "./utils";
+import {makeEm} from "./units";
 import {spacings, tightSpacings} from "./spacingData";
 import {_htmlGroupBuilders as groupBuilders} from "./defineFunction";
 import {DocumentFragment} from "./tree";
@@ -299,9 +300,9 @@ function buildHTMLUnbreakable(children, options) {
     // the height of the expression, and the bottom of the HTML element
     // falls at the depth of the expression.
     const strut = makeSpan(["strut"]);
-    strut.style.height = (body.height + body.depth) + "em";
+    strut.style.height = makeEm(body.height + body.depth);
     if (body.depth) {
-        strut.style.verticalAlign = -body.depth + "em";
+        strut.style.verticalAlign = makeEm(-body.depth);
     }
     body.children.unshift(strut);
 
@@ -395,9 +396,9 @@ export default function buildHTML(tree: AnyParseNode[], options: Options): DomSp
     // (the height of the enclosing htmlNode) for proper vertical alignment.
     if (tagChild) {
         const strut = tagChild.children[0];
-        strut.style.height = (htmlNode.height + htmlNode.depth) + "em";
+        strut.style.height = makeEm(htmlNode.height + htmlNode.depth);
         if (htmlNode.depth) {
-            strut.style.verticalAlign = (-htmlNode.depth) + "em";
+            strut.style.verticalAlign = makeEm(-htmlNode.depth);
         }
     }
 

src/delimiter.js

@@ -30,6 +30,7 @@ import buildCommon from "./buildCommon";
 import {getCharacterMetrics} from "./fontMetrics";
 import symbols from "./symbols";
 import utils from "./utils";
+import {makeEm} from "./units";
 import fontMetricsData from "./fontMetricsData";
 
 import type Options from "./Options";
@@ -93,7 +94,7 @@ const centerSpan = function(
         options.fontMetrics().axisHeight;
 
     span.classes.push("delimcenter");
-    span.style.top = shift + "em";
+    span.style.top = makeEm(shift);
     span.height -= shift;
     span.depth += shift;
 };
@@ -186,21 +187,21 @@ const makeInner = function(
 ): VListElem {
     // Create a span with inline SVG for the inner part of a tall stacked delimiter.
     const width = fontMetricsData['Size4-Regular'][ch.charCodeAt(0)]
-        ? fontMetricsData['Size4-Regular'][ch.charCodeAt(0)][4].toFixed(3)
-        : fontMetricsData['Size1-Regular'][ch.charCodeAt(0)][4].toFixed(3);
+        ? fontMetricsData['Size4-Regular'][ch.charCodeAt(0)][4]
+        : fontMetricsData['Size1-Regular'][ch.charCodeAt(0)][4];
     const path = new PathNode("inner", innerPath(ch,  Math.round(1000 * height)));
     const svgNode = new SvgNode([path], {
-        "width": width + "em",
-        "height": height + "em",
+        "width": makeEm(width),
+        "height": makeEm(height),
         // Override CSS rule `.katex svg { width: 100% }`
-        "style": "width:" + width + "em",
+        "style": "width:" + makeEm(width),
         "viewBox": "0 0 " + 1000 * width + " " + Math.round(1000 * height),
         "preserveAspectRatio": "xMinYMin",
     });
     const span = buildCommon.makeSvgSpan([], [svgNode], options);
     span.height = height;
-    span.style.height = height + "em";
-    span.style.width = width + "em";
+    span.style.height = makeEm(height);
+    span.style.width = makeEm(width);
     return {type: "elem", elem: span};
 };
 
@@ -427,7 +428,7 @@ const sqrtSvg = function(
     const svg =  new SvgNode([pathNode], {
         // Note: 1000:1 ratio of viewBox to document em width.
         "width": "400em",
-        "height": height + "em",
+        "height": makeEm(height),
         "viewBox": "0 0 400000 " + viewBoxHeight,
         "preserveAspectRatio": "xMinYMin slice",
     });
@@ -514,7 +515,7 @@ const makeSqrtImage = function(
     }
 
     span.height = texHeight;
-    span.style.height = spanHeight + "em";
+    span.style.height = makeEm(spanHeight);
 
     return {
         span,

src/domTree.js

@@ -16,6 +16,7 @@ import utils from "./utils";
 import {path} from "./svgGeometry";
 import type Options from "./Options";
 import {DocumentFragment} from "./tree";
+import {makeEm} from "./units";
 
 import type {VirtualNode} from "./tree";
 
@@ -406,7 +407,7 @@ export class SymbolNode implements HtmlDomNode {
 
         if (this.italic > 0) {
             span = document.createElement("span");
-            span.style.marginRight = this.italic + "em";
+            span.style.marginRight = makeEm(this.italic);
         }
 
         if (this.classes.length > 0) {

src/environments/array.js

@@ -8,7 +8,7 @@ import mathMLTree from "../mathMLTree";
 import ParseError from "../ParseError";
 import {assertNodeType, assertSymbolNodeType} from "../parseNode";
 import {checkSymbolNodeType} from "../parseNode";
-import {calculateSize} from "../units";
+import {calculateSize, makeEm} from "../units";
 import utils from "../utils";
 
 import * as html from "../buildHTML";
@@ -368,7 +368,7 @@ const htmlBuilder: HtmlBuilder<"array"> = function(group, options) {
             if (!firstSeparator) {
                 colSep = buildCommon.makeSpan(["arraycolsep"], []);
                 colSep.style.width =
-                    options.fontMetrics().doubleRuleSep + "em";
+                    makeEm(options.fontMetrics().doubleRuleSep);
                 cols.push(colSep);
             }
 
@@ -377,13 +377,13 @@ const htmlBuilder: HtmlBuilder<"array"> = function(group, options) {
                 const separator = buildCommon.makeSpan(
                     ["vertical-separator"], [], options
                 );
-                separator.style.height = totalHeight + "em";
-                separator.style.borderRightWidth = `${ruleThickness}em`;
+                separator.style.height = makeEm(totalHeight);
+                separator.style.borderRightWidth = makeEm(ruleThickness);
                 separator.style.borderRightStyle = lineType;
-                separator.style.margin = `0 -${ruleThickness / 2}em`;
+                separator.style.margin = `0 ${makeEm(-ruleThickness / 2)}`;
                 const shift = totalHeight - offset;
                 if (shift) {
-                    separator.style.verticalAlign = -shift + "em";
+                    separator.style.verticalAlign = makeEm(-shift);
                 }
 
                 cols.push(separator);
@@ -406,7 +406,7 @@ const htmlBuilder: HtmlBuilder<"array"> = function(group, options) {
             sepwidth = utils.deflt(colDescr.pregap, arraycolsep);
             if (sepwidth !== 0) {
                 colSep = buildCommon.makeSpan(["arraycolsep"], []);
-                colSep.style.width = sepwidth + "em";
+                colSep.style.width = makeEm(sepwidth);
                 cols.push(colSep);
             }
         }
@@ -437,7 +437,7 @@ const htmlBuilder: HtmlBuilder<"array"> = function(group, options) {
             sepwidth = utils.deflt(colDescr.postgap, arraycolsep);
             if (sepwidth !== 0) {
                 colSep = buildCommon.makeSpan(["arraycolsep"], []);
-                colSep.style.width = sepwidth + "em";
+                colSep.style.width = makeEm(sepwidth);
                 cols.push(colSep);
             }
         }
@@ -523,7 +523,7 @@ const mathmlBuilder: MathMLBuilder<"array"> = function(group, options) {
     const gap = (group.arraystretch === 0.5)
         ? 0.1  // {smallmatrix}, {subarray}
         : 0.16 + group.arraystretch - 1 + (group.addJot ? 0.09 : 0);
-    table.setAttribute("rowspacing", gap.toFixed(4) + "em");
+    table.setAttribute("rowspacing", makeEm(gap));
 
     // MathML table lines go only between cells.
     // To place a line on an edge we'll use <menclose>, if necessary.

src/environments/cd.js

@@ -6,6 +6,7 @@ import * as html from "../buildHTML";
 import * as mml from "../buildMathML";
 import {assertSymbolNodeType} from "../parseNode";
 import ParseError from "../ParseError";
+import {makeEm} from "../units";
 
 import type Parser from "../Parser";
 import type {ParseNode, AnyParseNode} from "../parseNode";
@@ -257,7 +258,7 @@ defineFunction({
         const label = buildCommon.wrapFragment(
             html.buildGroup(group.label, newOptions, options), options);
         label.classes.push("cd-label-" + group.side);
-        label.style.bottom = (0.8 - label.depth) + "em";
+        label.style.bottom = makeEm(0.8 - label.depth);
         // Zero out label height & depth, so vertical align of arrow is set
         // by the arrow height, not by the label.
         label.height = 0;

src/functions/accent.js

@@ -6,6 +6,7 @@ import utils from "../utils";
 import stretchy from "../stretchy";
 import {assertNodeType} from "../parseNode";
 import {assertSpan, assertSymbolDomNode} from "../domTree";
+import {makeEm} from "../units";
 
 import * as html from "../buildHTML";
 import * as mml from "../buildMathML";
@@ -131,7 +132,7 @@ export const htmlBuilder: HtmlBuilderSupSub<"accent"> = (grp, options) => {
             left -= width / 2;
         }
 
-        accentBody.style.left = left + "em";
+        accentBody.style.left = makeEm(left);
 
         // \textcircled uses the \bigcirc glyph, so it needs some
         // vertical adjustment to match LaTeX.
@@ -161,8 +162,8 @@ export const htmlBuilder: HtmlBuilderSupSub<"accent"> = (grp, options) => {
                     wrapperClasses: ["svg-align"],
                     wrapperStyle: skew > 0
                         ? {
-                            width: `calc(100% - ${2 * skew}em)`,
-                            marginLeft: `${(2 * skew)}em`,
+                            width: `calc(100% - ${makeEm(2 * skew)})`,
+                            marginLeft: makeEm(2 * skew),
                         }
                         : undefined,
                 },

src/functions/cr.js

@@ -4,7 +4,7 @@
 import defineFunction from "../defineFunction";
 import buildCommon from "../buildCommon";
 import mathMLTree from "../mathMLTree";
-import {calculateSize} from "../units";
+import {calculateSize, makeEm} from "../units";
 import {assertNodeType} from "../parseNode";
 
 // \DeclareRobustCommand\\{...\@xnewline}
@@ -41,7 +41,7 @@ defineFunction({
             span.classes.push("newline");
             if (group.size) {
                 span.style.marginTop =
-                    calculateSize(group.size, options) + "em";
+                    makeEm(calculateSize(group.size, options));
             }
         }
         return span;
@@ -53,7 +53,7 @@ defineFunction({
             node.setAttribute("linebreak", "newline");
             if (group.size) {
                 node.setAttribute("height",
-                    calculateSize(group.size, options) + "em");
+                    makeEm(calculateSize(group.size, options)));
             }
         }
         return node;

src/functions/delimsizing.js

@@ -6,6 +6,7 @@ import mathMLTree from "../mathMLTree";
 import ParseError from "../ParseError";
 import utils from "../utils";
 import {assertNodeType, checkSymbolNodeType} from "../parseNode";
+import {makeEm} from "../units";
 
 import * as html from "../buildHTML";
 import * as mml from "../buildMathML";
@@ -126,8 +127,9 @@ defineFunction({
         }
 
         node.setAttribute("stretchy", "true");
-        node.setAttribute("minsize", delimiter.sizeToMaxHeight[group.size] + "em");
-        node.setAttribute("maxsize", delimiter.sizeToMaxHeight[group.size] + "em");
+        const size = makeEm(delimiter.sizeToMaxHeight[group.size]);
+        node.setAttribute("minsize", size);
+        node.setAttribute("maxsize", size);
 
         return node;
     },

src/functions/enclose.js

@@ -6,7 +6,7 @@ import utils from "../utils";
 import stretchy from "../stretchy";
 import {phasePath} from "../svgGeometry";
 import {PathNode, SvgNode} from "../domTree";
-import {calculateSize} from "../units";
+import {calculateSize, makeEm} from "../units";
 import {assertNodeType} from "../parseNode";
 
 import * as html from "../buildHTML";
@@ -48,20 +48,20 @@ const htmlBuilder = (group, options) => {
 
         const angleHeight = inner.height + inner.depth + lineWeight + clearance;
         // Reserve a left pad for the angle.
-        inner.style.paddingLeft = (angleHeight / 2 + lineWeight) + "em";
+        inner.style.paddingLeft = makeEm(angleHeight / 2 + lineWeight);
 
         // Create an SVG
         const viewBoxHeight = Math.floor(1000 * angleHeight * scale);
         const path = phasePath(viewBoxHeight);
         const svgNode = new SvgNode([new PathNode("phase", path)], {
             "width": "400em",
-            "height": `${viewBoxHeight / 1000}em`,
+            "height": makeEm(viewBoxHeight / 1000),
             "viewBox": `0 0 400000 ${viewBoxHeight}`,
             "preserveAspectRatio": "xMinYMin slice",
         });
         // Wrap it in a span with overflow: hidden.
         img = buildCommon.makeSvgSpan(["hide-tail"], [svgNode], options);
-        img.style.height = angleHeight + "em";
+        img.style.height = makeEm(angleHeight);
         imgShift = inner.depth + lineWeight + clearance;
 
     } else {
@@ -104,10 +104,10 @@ const htmlBuilder = (group, options) => {
         img = stretchy.encloseSpan(inner, label, topPad, bottomPad, options);
         if (/fbox|boxed|fcolorbox/.test(label)) {
             img.style.borderStyle = "solid";
-            img.style.borderWidth = `${ruleThickness}em`;
+            img.style.borderWidth = makeEm(ruleThickness);
         } else if (label === "angl" && ruleThickness !== 0.049) {
-            img.style.borderTopWidth = `${ruleThickness}em`;
-            img.style.borderRightWidth = `${ruleThickness}em`;
+            img.style.borderTopWidth = makeEm(ruleThickness);
+            img.style.borderRightWidth = makeEm(ruleThickness);
         }
         imgShift = inner.depth + bottomPad;
 

src/functions/genfrac.js

@@ -9,7 +9,7 @@ import {assert} from "../utils";
 
 import * as html from "../buildHTML";
 import * as mml from "../buildMathML";
-import {calculateSize} from "../units";
+import {calculateSize, makeEm} from "../units";
 
 const adjustStyle = (size, originalStyle) => {
     // Figure out what style this fraction should be in based on the
@@ -196,7 +196,7 @@ const mathmlBuilder = (group, options) => {
         node.setAttribute("linethickness", "0px");
     } else if (group.barSize) {
         const ruleWidth = calculateSize(group.barSize, options);
-        node.setAttribute("linethickness", ruleWidth + "em");
+        node.setAttribute("linethickness", makeEm(ruleWidth));
     }
 
     const style = adjustStyle(group.size, options.style);

src/functions/includegraphics.js

@@ -1,7 +1,7 @@
 // @flow
 import defineFunction from "../defineFunction";
 import type {Measurement} from "../units";
-import {calculateSize, validUnit} from "../units";
+import {calculateSize, validUnit, makeEm} from "../units";
 import ParseError from "../ParseError";
 import {Img} from "../domTree";
 import mathMLTree from "../mathMLTree";
@@ -108,7 +108,6 @@ defineFunction({
 
         if (group.totalheight.number > 0) {
             depth = calculateSize(group.totalheight, options) - height;
-            depth = Number(depth.toFixed(2));
         }
 
         let width = 0;
@@ -116,12 +115,12 @@ defineFunction({
             width = calculateSize(group.width, options);
         }
 
-        const style: CssStyle = {height: height + depth + "em"};
+        const style: CssStyle = {height: makeEm(height + depth)};
         if (width > 0) {
-            style.width = width + "em";
+            style.width = makeEm(width);
         }
         if (depth > 0) {
-            style.verticalAlign = -depth + "em";
+            style.verticalAlign = makeEm(-depth);
         }
 
         const node = new Img(group.src, group.alt, style);
@@ -138,14 +137,13 @@ defineFunction({
         let depth = 0;
         if (group.totalheight.number > 0) {
             depth = calculateSize(group.totalheight, options) - height;
-            depth = depth.toFixed(2);
-            node.setAttribute("valign", "-" + depth + "em");
+            node.setAttribute("valign", makeEm(-depth));
         }
-        node.setAttribute("height", height + depth + "em");
+        node.setAttribute("height", makeEm(height + depth));
 
         if (group.width.number > 0) {
             const width = calculateSize(group.width, options);
-            node.setAttribute("width", width + "em");
+            node.setAttribute("width", makeEm(width));
         }
         node.setAttribute("src", group.src);
         return node;

src/functions/lap.js

@@ -3,6 +3,7 @@
 import defineFunction from "../defineFunction";
 import buildCommon from "../buildCommon";
 import mathMLTree from "../mathMLTree";
+import {makeEm} from "../units";
 
 import * as html from "../buildHTML";
 import * as mml from "../buildMathML";
@@ -46,9 +47,9 @@ defineFunction({
         // Otherwise, a tall argument may be misplaced.
         // This code resolved issue #1153
         const strut = buildCommon.makeSpan(["strut"]);
-        strut.style.height = (node.height + node.depth) + "em";
+        strut.style.height = makeEm(node.height + node.depth);
         if (node.depth) {
-            strut.style.verticalAlign = -node.depth + "em";
+            strut.style.verticalAlign = makeEm(-node.depth);
         }
         node.children.unshift(strut);
 

src/functions/op.js

@@ -8,6 +8,7 @@ import utils from "../utils";
 import Style from "../Style";
 import {assembleSupSub} from "./utils/assembleSupSub";
 import {assertNodeType} from "../parseNode";
+import {makeEm} from "../units";
 
 import * as html from "../buildHTML";
 import * as mml from "../buildMathML";
@@ -132,7 +133,7 @@ export const htmlBuilder: HtmlBuilderSupSub<"op"> = (grp, options) => {
     } else {
         if (baseShift) {
             base.style.position = "relative";
-            base.style.top = baseShift + "em";
+            base.style.top = makeEm(baseShift);
         }
 
         return base;

src/functions/rule.js

@@ -3,7 +3,7 @@ import buildCommon from "../buildCommon";
 import defineFunction from "../defineFunction";
 import mathMLTree from "../mathMLTree";
 import {assertNodeType} from "../parseNode";
-import {calculateSize} from "../units";
+import {calculateSize, makeEm} from "../units";
 
 defineFunction({
     type: "rule",
@@ -35,9 +35,9 @@ defineFunction({
         const shift = (group.shift) ? calculateSize(group.shift, options) : 0;
 
         // Style the rule to the right size
-        rule.style.borderRightWidth = width + "em";
-        rule.style.borderTopWidth = height + "em";
-        rule.style.bottom = shift + "em";
+        rule.style.borderRightWidth = makeEm(width);
+        rule.style.borderTopWidth = makeEm(height);
+        rule.style.bottom = makeEm(shift);
 
         // Record the height and width
         rule.width = width;
@@ -58,17 +58,17 @@ defineFunction({
 
         const rule = new mathMLTree.MathNode("mspace");
         rule.setAttribute("mathbackground", color);
-        rule.setAttribute("width", width + "em");
-        rule.setAttribute("height", height + "em");
+        rule.setAttribute("width", makeEm(width));
+        rule.setAttribute("height", makeEm(height));
 
         const wrapper = new mathMLTree.MathNode("mpadded", [rule]);
         if (shift >= 0) {
-            wrapper.setAttribute("height", "+" + shift + "em");
+            wrapper.setAttribute("height", makeEm(shift));
         } else {
-            wrapper.setAttribute("height", shift + "em");
-            wrapper.setAttribute("depth", "+" + (-shift) + "em");
+            wrapper.setAttribute("height", makeEm(shift));
+            wrapper.setAttribute("depth", makeEm(-shift));
         }
-        wrapper.setAttribute("voffset", shift + "em");
+        wrapper.setAttribute("voffset", makeEm(shift));
 
         return wrapper;
     },

src/functions/sizing.js

@@ -2,6 +2,7 @@
 import buildCommon from "../buildCommon";
 import defineFunction from "../defineFunction";
 import mathMLTree from "../mathMLTree";
+import {makeEm} from "../units";
 
 import * as html from "../buildHTML";
 import * as mml from "../buildMathML";
@@ -83,7 +84,7 @@ defineFunction({
         // in, so we can't reset the size to normal before changing it.  Now
         // that we're passing an options parameter we should be able to fix
         // this.
-        node.setAttribute("mathsize", newOptions.sizeMultiplier + "em");
+        node.setAttribute("mathsize", makeEm(newOptions.sizeMultiplier));
 
         return node;
     },

src/functions/sqrt.js

@@ -4,6 +4,7 @@ import buildCommon from "../buildCommon";
 import mathMLTree from "../mathMLTree";
 import delimiter from "../delimiter";
 import Style from "../Style";
+import {makeEm} from "../units";
 
 import * as html from "../buildHTML";
 import * as mml from "../buildMathML";
@@ -70,7 +71,7 @@ defineFunction({
         // Shift the sqrt image
         const imgShift = img.height - inner.height - lineClearance - ruleWidth;
 
-        inner.style.paddingLeft = advanceWidth + "em";
+        inner.style.paddingLeft = makeEm(advanceWidth);
 
         // Overlay the image and the argument.
         const body = buildCommon.makeVList({

src/functions/supsub.js

@@ -4,6 +4,7 @@ import buildCommon from "../buildCommon";
 import {SymbolNode} from "../domTree";
 import mathMLTree from "../mathMLTree";
 import utils from "../utils";
+import {makeEm} from "../units";
 import Style from "../Style";
 
 import * as html from "../buildHTML";
@@ -111,7 +112,7 @@ defineFunctionBuilders({
         // scriptspace is a font-size-independent size, so scale it
         // appropriately for use as the marginRight.
         const multiplier = options.sizeMultiplier;
-        const marginRight = (0.5 / metrics.ptPerEm) / multiplier + "em";
+        const marginRight = makeEm((0.5 / metrics.ptPerEm) / multiplier);
 
         let marginLeft = null;
         if (subm) {
@@ -123,7 +124,7 @@ defineFunctionBuilders({
                 (group.base.name === "\\oiint" || group.base.name === "\\oiiint");
             if (base instanceof SymbolNode || isOiint) {
                 // $FlowFixMe
-                marginLeft = -base.italic + "em";
+                marginLeft = makeEm(-base.italic);
             }
         }
 

src/functions/utils/assembleSupSub.js

@@ -6,6 +6,7 @@ import type {StyleInterface} from "../../Style";
 import type Options from "../../Options";
 import type {DomSpan, SymbolNode} from "../../domTree";
 import type {AnyParseNode} from "../../parseNode";
+import {makeEm} from "../../units";
 
 // For an operator with limits, assemble the base, sup, and sub into a span.
 
@@ -62,11 +63,11 @@ export const assembleSupSub = (
             positionData: bottom,
             children: [
                 {type: "kern", size: options.fontMetrics().bigOpSpacing5},
-                {type: "elem", elem: sub.elem, marginLeft: -slant + "em"},
+                {type: "elem", elem: sub.elem, marginLeft: makeEm(-slant)},
                 {type: "kern", size: sub.kern},
                 {type: "elem", elem: base},
                 {type: "kern", size: sup.kern},
-                {type: "elem", elem: sup.elem, marginLeft: slant + "em"},
+                {type: "elem", elem: sup.elem, marginLeft: makeEm(slant)},
                 {type: "kern", size: options.fontMetrics().bigOpSpacing5},
             ],
         }, options);
@@ -82,7 +83,7 @@ export const assembleSupSub = (
             positionData: top,
             children: [
                 {type: "kern", size: options.fontMetrics().bigOpSpacing5},
-                {type: "elem", elem: sub.elem, marginLeft: -slant + "em"},
+                {type: "elem", elem: sub.elem, marginLeft: makeEm(-slant)},
                 {type: "kern", size: sub.kern},
                 {type: "elem", elem: base},
             ],
@@ -96,7 +97,7 @@ export const assembleSupSub = (
             children: [
                 {type: "elem", elem: base},
                 {type: "kern", size: sup.kern},
-                {type: "elem", elem: sup.elem, marginLeft: slant + "em"},
+                {type: "elem", elem: sup.elem, marginLeft: makeEm(slant)},
                 {type: "kern", size: options.fontMetrics().bigOpSpacing5},
             ],
         }, options);
@@ -112,7 +113,7 @@ export const assembleSupSub = (
         // A negative margin-left was applied to the lower limit.
         // Avoid an overlap by placing a spacer on the left on the group.
         const spacer = buildCommon.makeSpan(["mspace"], [], options);
-        spacer.style.marginRight = `${slant}em`;
+        spacer.style.marginRight = makeEm(slant);
         parts.unshift(spacer);
     }
     return buildCommon.makeSpan(["mop", "op-limits"], parts, options);

src/macros.js

@@ -13,6 +13,7 @@ import fontMetricsData from "./fontMetricsData";
 import functions from "./functions";
 import symbols from "./symbols";
 import utils from "./utils";
+import {makeEm} from "./units";
 import ParseError from "./ParseError";
 
 
@@ -634,8 +635,8 @@ defineMacro("\\TeX", "\\textrm{\\html@mathml{" +
 // boxes, though visually the A appears to extend above slightly).
 // We compute the corresponding \raisebox when A is rendered in \normalsize
 // \scriptstyle, which has a scale factor of 0.7 (see Options.js).
-const latexRaiseA = fontMetricsData['Main-Regular']["T".charCodeAt(0)][1] -
-    0.7 * fontMetricsData['Main-Regular']["A".charCodeAt(0)][1] + "em";
+const latexRaiseA = makeEm(fontMetricsData['Main-Regular']["T".charCodeAt(0)][1] -
+    0.7 * fontMetricsData['Main-Regular']["A".charCodeAt(0)][1]);
 defineMacro("\\LaTeX", "\\textrm{\\html@mathml{" +
     `L\\kern-.36em\\raisebox{${latexRaiseA}}{\\scriptstyle A}` +
     "\\kern-.15em\\TeX}{LaTeX}}");

src/mathMLTree.js

@@ -12,6 +12,7 @@
 import utils from "./utils";
 import {DocumentFragment} from "./tree";
 import {createClass} from "./domTree";
+import {makeEm} from "./units";
 
 import type {VirtualNode} from "./tree";
 
@@ -219,7 +220,7 @@ class SpaceNode implements MathDomNode {
         } else {
             const node = document.createElementNS(
                 "http://www.w3.org/1998/Math/MathML", "mspace");
-            node.setAttribute("width", this.width + "em");
+            node.setAttribute("width", makeEm(this.width));
             return node;
         }
     }
@@ -231,7 +232,7 @@ class SpaceNode implements MathDomNode {
         if (this.character) {
             return `<mtext>${this.character}</mtext>`;
         } else {
-            return `<mspace width="${this.width}em"/>`;
+            return `<mspace width="${makeEm(this.width)}"/>`;
         }
     }
 

src/stretchy.js

@@ -9,6 +9,7 @@ import {LineNode, PathNode, SvgNode} from "./domTree";
 import buildCommon from "./buildCommon";
 import mathMLTree from "./mathMLTree";
 import utils from "./utils";
+import {makeEm} from "./units";
 
 import type Options from "./Options";
 import type {ParseNode, AnyParseNode} from "./parseNode";
@@ -233,7 +234,7 @@ const svgSpan = function(
             const path = new PathNode(pathName);
             const svgNode = new SvgNode([path], {
                 "width": "100%",
-                "height": height + "em",
+                "height": makeEm(height),
                 "viewBox": `0 0 ${viewBoxWidth} ${viewBoxHeight}`,
                 "preserveAspectRatio": "none",
             });
@@ -274,7 +275,7 @@ const svgSpan = function(
 
                 const svgNode = new SvgNode([path], {
                     "width": "400em",
-                    "height": height + "em",
+                    "height": makeEm(height),
                     "viewBox": `0 0 ${viewBoxWidth} ${viewBoxHeight}`,
                     "preserveAspectRatio": aligns[i] + " slice",
                 });
@@ -284,7 +285,7 @@ const svgSpan = function(
                 if (numSvgChildren === 1) {
                     return {span, minWidth, height};
                 } else {
-                    span.style.height = height + "em";
+                    span.style.height = makeEm(height);
                     spans.push(span);
                 }
             }
@@ -301,9 +302,9 @@ const svgSpan = function(
     // Note that we are returning span.depth = 0.
     // Any adjustments relative to the baseline must be done in buildHTML.
     span.height = height;
-    span.style.height = height + "em";
+    span.style.height = makeEm(height);
     if (minWidth > 0) {
-        span.style.minWidth = minWidth + "em";
+        span.style.minWidth = makeEm(minWidth);
     }
 
     return span;
@@ -358,14 +359,14 @@ const encloseSpan = function(
 
         const svgNode = new SvgNode(lines, {
             "width": "100%",
-            "height": totalHeight + "em",
+            "height": makeEm(totalHeight),
         });
 
         img = buildCommon.makeSvgSpan([], [svgNode], options);
     }
 
     img.height = totalHeight;
-    img.style.height = totalHeight + "em";
+    img.style.height = makeEm(totalHeight);
 
     return img;
 };

src/units.js

@@ -96,3 +96,11 @@ export const calculateSize = function(
     }
     return Math.min(sizeValue.number * scale, options.maxSize);
 };
+
+/**
+ * Round `n` to 4 decimal places, or to the nearest 1/10,000th em. See
+ * https://github.com/KaTeX/KaTeX/pull/2460.
+ */
+export const makeEm = function(n: number): string {
+    return +n.toFixed(4) + "em";
+};

test/__snapshots__/katex-spec.js.snap

@@ -214,7 +214,7 @@ exports[`A font parser \\boldsymbol should inherit mbin/mrel from argument 1`] =
     "height": 0,
     "maxFontSize": 0,
     "style": {
-      "marginRight": "0.2777777777777778em"
+      "marginRight": "0.2778em"
     }
   },
   {
@@ -272,7 +272,7 @@ exports[`A font parser \\boldsymbol should inherit mbin/mrel from argument 1`] =
     "height": 0,
     "maxFontSize": 0,
     "style": {
-      "marginRight": "0.2777777777777778em"
+      "marginRight": "0.2778em"
     }
   },
   {
@@ -302,7 +302,7 @@ exports[`A font parser \\boldsymbol should inherit mbin/mrel from argument 1`] =
     "height": 0,
     "maxFontSize": 0,
     "style": {
-      "marginRight": "0.2222222222222222em"
+      "marginRight": "0.2222em"
     }
   },
   {
@@ -360,7 +360,7 @@ exports[`A font parser \\boldsymbol should inherit mbin/mrel from argument 1`] =
     "height": 0,
     "maxFontSize": 0,
     "style": {
-      "marginRight": "0.2222222222222222em"
+      "marginRight": "0.2222em"
     }
   },
   {
@@ -390,7 +390,7 @@ exports[`A font parser \\boldsymbol should inherit mbin/mrel from argument 1`] =
     "height": 0,
     "maxFontSize": 0,
     "style": {
-      "marginRight": "0.2222222222222222em"
+      "marginRight": "0.2222em"
     }
   },
   {
@@ -448,7 +448,7 @@ exports[`A font parser \\boldsymbol should inherit mbin/mrel from argument 1`] =
     "height": 0,
     "maxFontSize": 0,
     "style": {
-      "marginRight": "0.2222222222222222em"
+      "marginRight": "0.2222em"
     }
   },
   {
@@ -657,7 +657,7 @@ exports[`An HTML extension builder should not affect spacing 1`] = `
         "height": 0,
         "maxFontSize": 0,
         "style": {
-          "marginRight": "0.2222222222222222em"
+          "marginRight": "0.2222em"
         }
       },
       {
@@ -686,7 +686,7 @@ exports[`An HTML extension builder should not affect spacing 1`] = `
         "height": 0,
         "maxFontSize": 0,
         "style": {
-          "marginRight": "0.2222222222222222em"
+          "marginRight": "0.2222em"
         }
       }
     ],
@@ -1089,7 +1089,7 @@ exports[`Extending katex by new fonts and symbols Add new font class to new exte
   >
     <span class="base">
       <span class="strut"
-            style="height:0.84425em;"
+            style="height:0.8442em;"
       >
       </span>
       <span class="mord mockEasternArabicFont-Regular">
@@ -1103,7 +1103,7 @@ exports[`Extending katex by new fonts and symbols Add new font class to new exte
           <span class="vlist-t">
             <span class="vlist-r">
               <span class="vlist"
-                    style="height:0.84425em;"
+                    style="height:0.8442em;"
               >
                 <span style="top:-3.063em;margin-right:0.05em;">
                   <span class="pstrut"
@@ -1170,7 +1170,7 @@ exports[`Newlines via \\\\ and \\newline \\\\ causes newline, even after mrel an
   >
     <span class="base">
       <span class="strut"
-            style="height:0.68333em;"
+            style="height:0.6833em;"
       >
       </span>
       <span class="mord mathnormal"
@@ -1179,7 +1179,7 @@ exports[`Newlines via \\\\ and \\newline \\\\ causes newline, even after mrel an
         M
       </span>
       <span class="mspace"
-            style="margin-right:0.2777777777777778em;"
+            style="margin-right:0.2778em;"
       >
       </span>
       <span class="mrel">
@@ -1190,14 +1190,14 @@ exports[`Newlines via \\\\ and \\newline \\\\ causes newline, even after mrel an
     </span>
     <span class="base">
       <span class="strut"
-            style="height:0.66666em;vertical-align:-0.08333em;"
+            style="height:0.6667em;vertical-align:-0.0833em;"
       >
       </span>
       <span class="mord mathnormal">
         a
       </span>
       <span class="mspace"
-            style="margin-right:0.2222222222222222em;"
+            style="margin-right:0.2222em;"
       >
       </span>
       <span class="mbin">
@@ -1208,7 +1208,7 @@ exports[`Newlines via \\\\ and \\newline \\\\ causes newline, even after mrel an
     </span>
     <span class="base">
       <span class="strut"
-            style="height:0.69444em;"
+            style="height:0.6944em;"
       >
       </span>
       <span class="mord mathnormal">
@@ -1219,7 +1219,7 @@ exports[`Newlines via \\\\ and \\newline \\\\ causes newline, even after mrel an
     </span>
     <span class="base">
       <span class="strut"
-            style="height:0.43056em;"
+            style="height:0.4306em;"
       >
       </span>
       <span class="mord mathnormal">
@@ -1404,7 +1404,7 @@ exports[`href and url commands should not affect spacing around 1`] = `
     "height": 0,
     "maxFontSize": 0,
     "style": {
-      "marginRight": "0.2222222222222222em"
+      "marginRight": "0.2222em"
     }
   },
   {
@@ -1438,7 +1438,7 @@ exports[`href and url commands should not affect spacing around 1`] = `
         "height": 0,
         "maxFontSize": 0,
         "style": {
-          "marginRight": "0.2222222222222222em"
+          "marginRight": "0.2222em"
         }
       },
       {

test/__snapshots__/mathml-spec.js.snap

@@ -209,7 +209,7 @@ exports[`A MathML builder should build the CD environment properly 1`] = `
       display="block"
 >
   <semantics>
-    <mtable rowspacing="0.2500em"
+    <mtable rowspacing="0.25em"
             columnalign="center center center"
             columnspacing="0.5em"
     >