Charts: Animated update

[EvgeniyGT]

Hi!
Is there a way to update LineChartView data (ChartData) and redraw LineChartView animated from current position.
Like in appFigures application.
Thanks.

[danielgindi]

This is actually a feature that I thought about already, and planning to implement.
We have a lot on our plate right now - so in the meantime if this is really important to you - you could do this:

Create a function that takes dataset _A_, dataset _B_, and a _phase_ value between 0 and 1.
This function will:

1. Define a new dataset _C_
2. Iterate on each value in _A_, and set C[i] = (B[i] - A[i]) * phase + A[i]
3. Return _C_ as the new dataset

Now you should animate a simple number from 0 to 1, and pass it to the function along with the "from" dataset and "to" dataset. The result should be passed to the chart view :-)

You can also use the animation util in Charts, that can animate a number for you already, including easing and stuff.

So it's pretty much a peach of cake, and as soon as I can I'm planning on adding this to the library. But at least you have a solution for the meanwhile ;-)

[AlexEdunov]

Hi! Is it feature already implemented?

[AlexEdunov]

I need to animate adding new value to data set and changing position of limit line.

[apiejh]

Hi, I'm trying to apply the animation of data change in a pie chart. I already have the function you've mentioned but am struggling to find a way to "animate a simple number from 0 to 1". Any thoughts on this? Thanks!

[mlorenzeCDS]

Hello! The feature is already implemented?

[Salvar]

Adding my support for this feature, and also looking for a good way to interpolate a simple value according to some easing function (for the workaround). All the animation libraries seem to operate on views or properties, but I just want to "animate" the value of a simple number. Feels like it should be simple, maybe I'm looking in the wrong places?

[apiejh]

You might want to have a look at the post below where I've shared my solution. I'm aware that it is far from perfect but it seems to be working, which is nice. http://stackoverflow.com/questions/34730917/animating-a-double-from-0-to-1-in-swift-over-a-specified-interval/34774113#34774113

[Salvar]

Thanks for the quick reply @apiejh, really appreciate it. I managed to get this working with a timer function. Hacky, but works! At least until a better approach is available.

[anfriis]

Any updates or possible solutions for this ?

[4np]

+1, I have a chart with data and when some asynchronous process completes I would like to add either one or more new datasets and/or extend a dataset's datapoints (e.g. _live data_). It would be much more eye-pleasing if the chart would be able to animate those new datasets instead of rebuilding from scratch.

[gray419]

@kevinjtchen just put a PR out for this https://github.com/danielgindi/Charts/pull/2889

[kditraglia]

"You can also use the animation util in Charts, that can animate a number for you already, including easing and stuff."

I don't see any option to animate a single data-set only the whole chart. Am I missing something?

[delox]

It's been over two years, does anyone know how to implement this?

[nathan-fiscaletti]

Is this ever going to be implemented? I would love to be able to do something as simple as

lineChart.animate(to: newDataSet, duration: 1.0);

[nikoagge]

Just clear the array of old values and fill it with the new ones before calling again the setupChart()

[MihaelIsaev]

It is 2019 already and is there a solution for animate data changes without redrawing the whole chart from scratch? 🙂

[nathan-fiscaletti]

It's been over two years, does anyone know how to implement this?

It's been over four years now, something tells me we're never going to get this :(

[mrjko]

not sure why the PR #2889 is closed, but for those that still want some quick code snippets for danielgindis implementation: https://github.com/mrjko/testCharts/blob/master/chartsTest/BarChartViewController/BarChartViewController.swift

[vittorionapoli]

Does anyone know a way to do this for lineChart, I have to change dot position smoothly without redraw the whole chart.

[SSenocico]

@vittorionapoli You can use the same as @mrjko posted above, but replace it with LineChartDataSet

func partialResults(setA: LineChartDataSet, setB: LineChartDataSet, phase: Double) -> LineChartDataSet {
    let newSet = LineChartDataSet()

    for index in 0..<setA.entries.count {
        let currA = setA.entries[index].y
        let currB = setB.entries[index].y

        let newValue = (currB - currA) * phase + currA
        newSet.append(BarChartDataEntry(x: Double(index), y: newValue))
    }

    return newSet
}

@mrjko How the above method will work for an array of yValues for Stacked Bar Chart?
BarChartDataEntry(x: Double(index), yValues: [anArrayOfyValues])

[Skornos]

Updating the presented solution with LineChartDataSet and also it adds/removes new values from the dataSet if the size of the setA and setB is different.

    func partialResults(setA: LineChartDataSet, setB: LineChartDataSet, phase: Double) -> LineChartDataSet {
        let newSet = LineChartDataSet()
        let setACount = setA.entries.count
        let setBCount = setB.entries.count

        for index in 0..<min(setACount, setBCount) {
            let currA = setA.entries[index].y
            let currB = setB.entries[index].y

            let newValue = (currB - currA) * phase + currA
            newSet.append(ChartDataEntry(x: Double(index), y: newValue))
        }

        let diff = abs(setACount - setBCount)
        if setACount < setBCount {
            for index in setBCount - diff..<setBCount {
                let currB = setB.entries[index].y
                let newValue = currB
                newSet.append(ChartDataEntry(x: Double(index), y: newValue))
            }
        } else if setACount > setBCount {
            for index in setACount - diff..<setACount {
                let currA = setA.entries[index].y
                let newValue = currA
                newSet.append(ChartDataEntry(x: Double(index), y: newValue))
            }
        }

        return newSet
    }