Support for \raisebox (#685)

* Rough support for \raisebox

* Fix bounding box thanks to @kevinbarash and @ronkok

* Use calculateSize to support all currently supported units (ex, em, mu).
* Shift height and depth in all cases.

* Add screenshot test

* Rename transform -> raisebox

* Switch to normalsize in raisebox

* Attempt at using makeVList

* Significant rewrite, now working well

* rename textFunctionStyles to textFunctionFonts

src/buildHTML.js

@@ -304,7 +304,7 @@ groupTypes.ordgroup = function(group, options) {
 };
 
 groupTypes.text = function(group, options) {
-    const newOptions = options.withFont(group.value.style);
+    const newOptions = options.withFont(group.value.font);
     const inner = buildExpression(group.value.body, newOptions, true);
     for (let i = 0; i < inner.length - 1; i++) {
         if (inner[i].tryCombine(inner[i + 1])) {
@@ -1631,6 +1631,24 @@ groupTypes.mclass = function(group, options) {
     return makeSpan([group.value.mclass], elements, options);
 };
 
+groupTypes.raisebox = function(group, options) {
+    const body = groupTypes.sizing({value: {
+        value: [{
+            type: "text",
+            value: {
+                body: group.value.body,
+                font: "mathrm", // simulate \textrm
+            },
+        }],
+        size: 6,                // simulate \normalsize
+    }}, options);
+    const dy = units.calculateSize(group.value.dy.value, options);
+    return buildCommon.makeVList([{
+        type: "elem",
+        elem: body,
+    }], "shift", -dy, 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

src/buildMathML.js

@@ -601,6 +601,10 @@ groupTypes.mclass = function(group, options) {
     return new mathMLTree.MathNode("mstyle", inner);
 };
 
+// Transforms (translation/rotation) don't seem to have a representation
+// in MathML, so just treat them like \text{...}
+groupTypes.raisebox = groupTypes.text;
+
 /**
  * Takes a list of nodes, builds them, and returns a list of the generated
  * MathML nodes. A little simpler than the HTML version because we don't do any

src/functions.js

@@ -32,7 +32,7 @@ defineFunction("\\sqrt", {
 });
 
 // Non-mathy text, possibly in a font
-const textFunctionStyles = {
+const textFunctionFonts = {
     "\\text": undefined, "\\textrm": "mathrm", "\\textsf": "mathsf",
     "\\texttt": "mathtt", "\\textnormal": "mathrm", "\\textbf": "mathbf",
     "\\textit": "textit",
@@ -51,7 +51,7 @@ defineFunction([
     return {
         type: "text",
         body: ordargument(body),
-        style: textFunctionStyles[context.funcName],
+        font: textFunctionFonts[context.funcName],
     };
 });
 
@@ -650,3 +650,18 @@ defineFunction(["\\begin", "\\end"], {
         nameGroup: nameGroup,
     };
 });
+
+// Box manipulation
+defineFunction(["\\raisebox"], {
+    numArgs: 2,
+    argTypes: ["size", "text"],
+    allowedInText: true,
+}, function(context, args) {
+    const amount = args[0];
+    const body = args[1];
+    return {
+        type: "raisebox",
+        dy: amount,
+        body: ordargument(body),
+    };
+});

test/screenshotter/ss_data.yaml

@@ -186,6 +186,7 @@ OverUnderset: |
 Phantom: \dfrac{1+\phantom{x^{\blue{2}}} = x}{1+x^{\blue{2}} = x} \left(\vphantom{\int_t} zzz \right) \left( X \hphantom{\frac{\frac X X}{X}} \right)
 PrimeSpacing: f'+f_2'+f^{f'}
 PrimeSuper: x'^2+x'''^2+x'^2_3+x_3'^2
+Raisebox: \frac{a}{a\raisebox{0.5em}{b}} \cdot \frac{a\raisebox{-0.5em}{b}}{a} \cdot \sqrt{a\raisebox{0.5em}{b}} \cdot \sqrt{a\raisebox{-0.5em}{b}} \cdot \sqrt{a\raisebox{0.5em}{b}\raisebox{-0.5em}{b}}
 RelativeUnits: |
     \begin{array}{ll}
         a\kern1emb^{a\kern1emb^{a\kern1emb}} &