private int yPositionToOffset(int y, boolean beginLine) {
    if (myEditorScrollbarTop == -1 || myEditorTargetHeight == -1) {
      recalcEditorDimensions();
    }
    final int safeY = Math.max(0, y - myEditorScrollbarTop);
    VisualPosition visual;
    if (myEditorSourceHeight < myEditorTargetHeight) {
      visual = myEditor.xyToVisualPosition(new Point(0, safeY));
    } else {
      float fraction = Math.max(0, Math.min(1, safeY / (float) myEditorTargetHeight));
      final int lineCount = myEditorSourceHeight / myEditor.getLineHeight();
      visual = new VisualPosition((int) (fraction * lineCount), 0);
    }
    int line = myEditor.visualToLogicalPosition(visual).line;
    Document document = myEditor.getDocument();
    if (line < 0) return 0;
    if (line >= document.getLineCount()) return document.getTextLength();

    return beginLine ? document.getLineStartOffset(line) : document.getLineEndOffset(line);
  }