BarChart Didn't Show Correctly When Replacing Point in BarDataSet

[owenzhao]

    if let barChartData = barChartData {
        BarChart(chartData: barChartData)
            .touchOverlay(chartData: barChartData)
            .xAxisLabels(chartData: barChartData)
            .yAxisLabels(chartData: barChartData)
            .floatingInfoBox(chartData: barChartData)
    }

    private func appendBarChartData(_ log:DTLog, limit: Int) {
        let xAxisLabel = DateFormatter.localizedString(from: log.startTime, dateStyle: .none, timeStyle: .medium)
        let color = ColourStyle(colour: log.connected ? .green : .red)
        let point = BarChartDataPoint(value: Double(log.delay), xAxisLabel: xAxisLabel, colour: color)
        let style = BarStyle(barWidth: 1, cornerRadius: CornerRadius(topLeft: 5, topRight: 5, bottomLeft: 5, bottomRight: 5),
                             colourFrom: .barStyle, colour: color)

        if barChartData == nil {
            let points = (1...limit).map { _ in getEmptyBarChartDataPoint() }
            barChartData = BarChartData(dataSets: BarDataSet(dataPoints: points),
                                        barStyle: style)
        }

        if let barChartData = barChartData {
            if let zeroIndex = barChartData.dataSets.dataPoints.firstIndex(where: { $0.value == 0 }) {
                barChartData.dataSets.dataPoints[zeroIndex] = point
            } else {
                barChartData.dataSets.dataPoints.removeFirst()
                barChartData.dataSets.dataPoints.append(point)
            }
        }
    }

    private func getEmptyBarChartDataPoint() -> BarChartDataPoint {
        return BarChartDataPoint(value: 0, colour: .init(colour: .yellow))
    }

When the app ran, the bar chart didn't show properly. The overlay and info box were correct. But the bar didn't draw.

https://user-images.githubusercontent.com/2182896/165194101-6a525950-dfe9-40ef-9dc6-cc7417bd7e0e.mov

[owenzhao]

A Workaround I found was to recreate BarChartData each time.

private func appendBarChartData(_ log:DTLog, limit: Int) {
        let xAxisLabel = DateFormatter.localizedString(from: log.startTime, dateStyle: .none, timeStyle: .medium)
        let color = ColourStyle(colour: log.connected ? .green : .red)
        let point = BarChartDataPoint(value: Double(log.delay), xAxisLabel: xAxisLabel, colour: color)
        let style = BarStyle(barWidth: 1, cornerRadius: CornerRadius(topLeft: 5, topRight: 5, bottomLeft: 5, bottomRight: 5),
                             colourFrom: .barStyle, colour: color)

        if barChartData == nil {
            let points = (1...limit).map { _ in getEmptyBarChartDataPoint() }
            barChartData = BarChartData(dataSets: BarDataSet(dataPoints: points),
                                        barStyle: style)
        }

        if let barChartData = barChartData {
            var points = barChartData.dataSets.dataPoints
            points.removeFirst()
            points.append(point)
            self.barChartData = BarChartData(dataSets: BarDataSet(dataPoints: points),
                                        barStyle: style)
        }
    }

[willdale]

v2.10.0 should fix this.

[owenzhao]

I forked this project and I thought for a period updated bar chart, my new animation was fitter.

https://github.com/owenzhao/SwiftUICharts