Function coordsChar

static/editor.md/lib/codemirror/lib/codemirror.js:2778–2797

(cm, x, y)

  // Compute the character position closest to the given coordinates.
  // Input must be lineSpace-local ("div" coordinate system).
  function coordsChar(cm, x, y) {
    var doc = cm.doc;
    y += cm.display.viewOffset;
    if (y < 0) return PosWithInfo(doc.first, 0, true, -1);
    var lineN = lineAtHeight(doc, y), last = doc.first + doc.size - 1;
    if (lineN > last)
      return PosWithInfo(doc.first + doc.size - 1, getLine(doc, last).text.length, true, 1);
    if (x < 0) x = 0;

    var lineObj = getLine(doc, lineN);
    for (;;) {
      var found = coordsCharInner(cm, lineObj, lineN, x, y);
      var merged = collapsedSpanAtEnd(lineObj);
      var mergedPos = merged && merged.find(0, true);
      if (merged && (found.ch > mergedPos.from.ch || found.ch == mergedPos.from.ch && found.xRel > 0))
        lineN = lineNo(lineObj = mergedPos.to.line);
      else
        return found;
    }
  }

  function coordsCharInner(cm, lineObj, lineNo, x, y) {
    var innerOff = y - heightAtLine(lineObj);