Function lineAtHeight

external/.scrollLibs.js:1046–1071

(chunk, h)

  // Find the line at the given vertical position, using the height
  // information in the document tree.
  function lineAtHeight(chunk, h) {
    var n = chunk.first
    outer: do {
      for (var i$1 = 0; i$1 < chunk.children.length; ++i$1) {
        var child = chunk.children[i$1],
          ch = child.height
        if (h < ch) {
          chunk = child
          continue outer
        }
        h -= ch
        n += child.chunkSize()
      }
      return n
    } while (!chunk.lines)
    var i = 0
    for (; i < chunk.lines.length; ++i) {
      var line = chunk.lines[i],
        lh = line.height
      if (h < lh) {
        break
      }
      h -= lh
    }
    return n + i
  }

  function isLine(doc, l) {
    return l >= doc.first && l < doc.first + doc.size