startTimer method

Implementation

void startTimer() {
  if (_key.currentContext != null) {
    final double widgetWidth = _key.currentContext!.findRenderObject()!.paintBounds.size.width;
    final double widgetHeight = _key.currentContext!.findRenderObject()!.paintBounds.size.height;

    timer = Timer.periodic(Duration(milliseconds: _timerRest), (final Timer timer) {
      final double maxScrollExtent = scrollController.position.maxScrollExtent;
      final double pixels = scrollController.position.pixels;
      if (pixels + _moveDistance >= maxScrollExtent) {
        if (widget.scrollAxis == Axis.horizontal) {
          position = (maxScrollExtent - screenWidth! * widget.ratioOfBlankToScreen + widgetWidth) / 2 - widgetWidth + pixels - maxScrollExtent;
        } else {
          position = (maxScrollExtent - screenHeight! * widget.ratioOfBlankToScreen + widgetHeight) / 2 - widgetHeight + pixels - maxScrollExtent;
        }
        scrollController.jumpTo(position);
      }
      position += _moveDistance;
      scrollController.animateTo(position, duration: Duration(milliseconds: _timerRest), curve: Curves.linear);
    });
  }
}