Negative Bar animation is gone if axis.inverted=true

[liuxuan30]

Negative Bar animation is gone if axis.inverted=true

The issue is found while reviewing #3650

What did you expect to happen?

negative bar animation should be fine when inverted is enabled

Charts Environment

Charts version/Branch/Commit Number:
Xcode version: 10
Swift version: 4.2
Platform(s) running Charts: iOS
macOS version running Xcode: 10.14

Demo Project

Just use below data set:

    func setDataCount(_ count: Int, range: Double) {
        let yVals = [
            BarChartDataEntry(x: 0, y: -10),
            BarChartDataEntry(x: 1, y: 20),
            BarChartDataEntry(x: 2, y: -30),
            BarChartDataEntry(x: 3, y: 15)
        ]
        
        var set1: BarChartDataSet! = nil

and add a breakpoint or code

chartView.leftAxis.inverted = true   // false

You will see the animation for pos. bars is fine, but the animation for neg. bars is gone if inverted = true. animation for neg. bars is fine when inverted = false