How do I clear drawn curves using chart?

My lvgl version is 8.1.1
The platform is F1C200S
I created a curve using chart and set it in lv_chart_set_update_mode so that when the maximum number of data I set is reached, it circulates the data curve. Now I have the following requirements:

  1. Every time I start to draw a curve, I want to draw it again after clearing the curve, so that I can ensure that the curve starts from the left side each time, instead of drawing at the end of the last time. What function should I call for implementation?
  2. I want to display the scale value of the Y-axis, I called lv_chart_set_axis_tick(chart, LV_CHART_AXIS_PRIMARY_Y, 10, 5, 6, 5, true, 20), but it doesn’t do anything.