Function textHeight

static/editor.md/lib/codemirror/lib/codemirror.js:2841–2858

(display)

  var measureText;
  // Compute the default text height.
  function textHeight(display) {
    if (display.cachedTextHeight != null) return display.cachedTextHeight;
    if (measureText == null) {
      measureText = elt("pre");
      // Measure a bunch of lines, for browsers that compute
      // fractional heights.
      for (var i = 0; i < 49; ++i) {
        measureText.appendChild(document.createTextNode("x"));
        measureText.appendChild(elt("br"));
      }
      measureText.appendChild(document.createTextNode("x"));
    }
    removeChildrenAndAdd(display.measure, measureText);
    var height = measureText.offsetHeight / 50;
    if (height > 3) display.cachedTextHeight = height;
    removeChildren(display.measure);
    return height || 1;
  }

  // Compute the default character width.
  function charWidth(display) {