Highlight text then press [ALT+X] to convert LaTeX commands to their unicode equivalent (ex. \pi → π)
// ==UserScript==
// @name LaTeX Unicode Shortcuts
// @namespace http://tampermonkey.net/
// @version 1.1
// @description Highlight text then press [ALT+X] to convert LaTeX commands to their unicode equivalent (ex. \pi → π)
// @author eyl327
// @match *://*/*
// @grant none
// ==/UserScript==
(function () {
'use strict';
var convert;
var dictLoaded = false;
/* source url for shortcut file */
var dictionarySource = "https://raw.githubusercontent.com/eyl327/LaTeX-Gboard-Dictionary/master/dictionary.txt";
/* fetch text file when requested */
function loadAsset(url, callback) {
var xhr = new XMLHttpRequest();
xhr.open("GET", url, false);
xhr.onreadystatechange = function () {
if (xhr.readyState === 4) {
if (xhr.status === 200 || xhr.status === 0) {
callback(xhr.responseText);
}
}
}
xhr.send();
}
/* on dictionary loaded callback */
function loaded(response) {
console.log("LaTeX Unicode Shortcuts has been loaded.");
/* generate dictionary from text file */
var dictArr = response.split("\n").slice(1);
var dictionary = {};
for (var i = 0, len = dictArr.length; i < len; ++i) {
var kvp = dictArr[i].split("\t");
dictionary[kvp[0]] = kvp[1];
}
/* conversion function */
convert = function (text) {
var result = text.replace(/{([A-Za-z0-9])}/g, '$1'); // {R} => R
for (var key in dictionary) {
var pattern = new RegExp(key.replace(/([[^$.|\\?*+(){}])/g, '\\$1') + "\\b", 'g'); // clean and escape key
var replaced = result.replace(pattern, dictionary[key]);
if (replaced.length < result.length) {
result = replaced;
}
}
return result;
};
dictLoaded = true;
}
/* get caret position within input box */
function getCaretPositionInputBox(el) {
if ("selectionStart" in el && document.activeElement == el) {
return {
start: el.selectionStart,
end: el.selectionEnd
};
}
else if (el.createTextRange) {
var sel = document.selection.createRange();
if (sel.parentElement() === el) {
var range = el.createTextRange();
range.moveToBookmark(sel.getBookmark());
for (var len = 0;
range.compareEndPoints("EndToStart", range) > 0;
range.moveEnd("character", -1)) {
len++;
}
range.setEndPoint("StartToStart", el.createTextRange());
for (var pos = { start: 0, end: len };
range.compareEndPoints("EndToStart", range) > 0;
range.moveEnd("character", -1)) {
pos.start++;
pos.end++;
}
return pos;
}
}
return -1;
}
/* set caret position within input box */
function setCaretPosition(el, pos) {
if (el.setSelectionRange) {
el.focus();
el.setSelectionRange(pos, pos);
}
else if (el.createTextRange) {
var range = el.createTextRange();
range.collapse(true);
range.moveEnd('character', pos);
range.moveStart('character', pos);
range.select();
}
}
function overwriteInputBoxText(activeEl, before, convertedText, after) {
// overwrite text
activeEl.value = before + convertedText + after;
// set cursor to be at end of selection
setCaretPosition(activeEl, before.length + convertedText.length);
}
function replaceConversionInElement(activeEl, fullText, start, end) {
var textToConvert = fullText.substring(start, end);
var before = fullText.substring(0, start);
var after = fullText.substring(end, fullText.length);
// convert selection
var convertedText = convert(textToConvert);
if ("value" in activeEl) {
overwriteInputBoxText(activeEl, before, convertedText, after);
}
}
/* convert hilighted text in active element */
function convertSelectionInputBox(activeEl) {
var caretRange = getCaretPositionInputBox(activeEl);
var selStart = caretRange.start;
var selEnd = caretRange.end;
var fullText = activeEl.value;
/* if selection is empty, find word at caret */
if (selStart == selEnd) {
// Find beginning and end of word
var left = fullText.slice(0, selStart + 1).search(/\S+$/);
var right = fullText.slice(selStart).search(/(\s|$)/);
/* convert the word at the caret selection */
replaceConversionInElement(activeEl, fullText, left, right + selStart)
}
/* else convert the selection */
else {
replaceConversionInElement(activeEl, fullText, selStart, selEnd);
}
}
/* convert hilighted text in active element */
function convertSelectionContentEditable(element) {
var NodeTree = {
// Used to find all DOM nodes in window.getSelection()
getInnerNodes: function (anchor, focus) {
var ancestor = NodeTree.lowestCommonAncestor(anchor, focus);
var childList = NodeTree.findChildrenList(ancestor);
var [i, j] = [childList.indexOf(anchor), childList.indexOf(focus)].sort();
return childList.slice(i, j + 1);
},
getNodeChain: function (node) {
var chain = [];
chain.push(node);
while (node.parentNode) {
node = node.parentNode;
chain.push(node);
}
return chain.reverse();
},
lowestCommonAncestor: function (anchor, focus) {
var uChain = NodeTree.getNodeChain(anchor);
var vChain = NodeTree.getNodeChain(focus);
var i;
for (i = 0; i < uChain.length; i++) {
if (uChain[i] !== vChain[i]) {
break
}
}
return uChain[i - 1]
},
findChildrenList: function (node) {
var list = []
var find = function (n) {
if (!n) {
return;
}
list.push(n);
for (var child of Array.from(n.childNodes || [])) {
find(child);
}
}
find(node);
return list;
}
}
var sel = element.ownerDocument.getSelection();
var selAN = sel.anchorNode;
var selFN = sel.focusNode;
var nodesBetweenNodes = NodeTree.getInnerNodes(selAN, selFN);
var startNode = nodesBetweenNodes[0];
var endNode = nodesBetweenNodes[nodesBetweenNodes.length - 1];
var selAO = sel.anchorOffset;
var selFO = sel.focusOffset;
var [startCursor, endCursor] = (startNode === selAN && selAO <= selFO) ? [selAO, selFO] : [selFO, selAO];
var cursor;
for (var node of nodesBetweenNodes) {
if (node.nodeType === 3) { // 3 = text type
var selStart = (node === nodesBetweenNodes[0]) ? startCursor : 0;
var selEnd = (node === nodesBetweenNodes[nodesBetweenNodes.length - 1]) ? endCursor : node.nodeValue.length;
var text = node.nodeValue;
selEnd = Math.min(text.length, selEnd);
var convertStart = selStart;
var convertEnd = selEnd;
// cursor is not a hilighted selection
if (selStart == selEnd) {
// Find beginning and end of word
convertStart = text.slice(0, selStart + 1).search(/\S+$/);
convertEnd = text.slice(selEnd).search(/(\s|$)/) + selStart;
}
/* convert the word at the caret selection */
var textToConvert = text.substring(convertStart, convertEnd);
var before = text.substring(0, convertStart);
var after = text.substring(convertEnd, text.length);
var convertedText = convert(textToConvert);
// replace in element
var result = before + convertedText + after;
cursor = Math.min(result.length, before.length + convertedText.length);
node.nodeValue = result;
}
}
sel.collapse(endNode, cursor)
}
/* detect ALT+X keyboard shortcut */
function enableLaTeXShortcuts(event) {
if (event.altKey && event.keyCode == 88) { // ALT+X
// load dictionary when first pressed
if (!dictLoaded) {
loadAsset(dictionarySource, loaded);
}
// convert selection
var activeEl = document.activeElement;
var activeElTag = activeEl.tagName.toLowerCase();
if (activeElTag == "textarea" || activeElTag == "input") {
convertSelectionInputBox(activeEl);
}
else if (activeEl.contentEditable) {
convertSelectionContentEditable(activeEl);
}
}
}
document.addEventListener('keydown', enableLaTeXShortcuts, true);
})();