iOS-Charts-Candle:chartView.yAxis's max and min mum auto change

When scrolling xAxis, how to make yAxix data full fill screen and yAxis max min data auto scale?

First, use Obj-C instead of Swift
I want to create a candle chartView with 200 data,but show 50 data per screen (maxVisibleCount=50). the total data of 200 may have the maximum like 2000 and minimum 1000,

BUT:may be the first 50 datas just range in 1000-1100.

When I set chartView.rightAxis.axisMaximum and axisMinimum after i get data from http request. all of the candle stick have been drawed on the chartView.
and the candle cannot change its height when i zooming chartView.

I did yAxis.axisMaximum and yAxis.axisMinimum in

"- (void)chartTranslated:(ChartViewBase *)chartView dX:(CGFloat)dX dY:(CGFloat)dY"

as yAxis’s max and min value changed by zoom,but the candle stick don’t change

so how can i change the height of candle sticks when my yAxis reset max and min value?
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