Added in a custom menubar

This is a copy of the ProseMirror/prosemirror-menu repo files
which suggest working from a fork of this.

These changes include the ability to select callouts
from the menubar.

resources/js/editor/menu/icons.js

@@ -0,0 +1,53 @@
+/**
+ * This file originates from https://github.com/ProseMirror/prosemirror-menu
+ * and is hence subject to the MIT license found here:
+ * https://github.com/ProseMirror/prosemirror-menu/blob/master/LICENSE
+ * @copyright Marijn Haverbeke and others
+ */
+
+const SVG = "http://www.w3.org/2000/svg"
+const XLINK = "http://www.w3.org/1999/xlink"
+
+const prefix = "ProseMirror-icon"
+
+function hashPath(path) {
+  let hash = 0
+  for (let i = 0; i < path.length; i++)
+    hash = (((hash << 5) - hash) + path.charCodeAt(i)) | 0
+  return hash
+}
+
+export function getIcon(icon) {
+  let node = document.createElement("div")
+  node.className = prefix
+  if (icon.path) {
+    let name = "pm-icon-" + hashPath(icon.path).toString(16)
+    if (!document.getElementById(name)) buildSVG(name, icon)
+    let svg = node.appendChild(document.createElementNS(SVG, "svg"))
+    svg.style.width = (icon.width / icon.height) + "em"
+    let use = svg.appendChild(document.createElementNS(SVG, "use"))
+    use.setAttributeNS(XLINK, "href", /([^#]*)/.exec(document.location)[1] + "#" + name)
+  } else if (icon.dom) {
+    node.appendChild(icon.dom.cloneNode(true))
+  } else {
+    node.appendChild(document.createElement("span")).textContent = icon.text || ''
+    if (icon.css) node.firstChild.style.cssText = icon.css
+  }
+  return node
+}
+
+function buildSVG(name, data) {
+  let collection = document.getElementById(prefix + "-collection")
+  if (!collection) {
+    collection = document.createElementNS(SVG, "svg")
+    collection.id = prefix + "-collection"
+    collection.style.display = "none"
+    document.body.insertBefore(collection, document.body.firstChild)
+  }
+  let sym = document.createElementNS(SVG, "symbol")
+  sym.id = name
+  sym.setAttribute("viewBox", "0 0 " + data.width + " " + data.height)
+  let path = sym.appendChild(document.createElementNS(SVG, "path"))
+  path.setAttribute("d", data.path)
+  collection.appendChild(sym)
+}