Charts: Bar width

[zykis]

Any way i can force bar width to be wider?

Yet, dataset with 1 entity works pretty well:

[hernanarber]

Hi @zykis:

First of All Set your barWidth for the BarChartDataSet:

chartData.barWidth = defaultbarwidth // I Put is as 0.4

Then what you can do is make an Outlet for the Width of the Chart Constraint like this:
(Drag from Storyboard)
@IBOutlet weak var layoutBarChartWidth: NSLayoutConstraint!

Then you can Set the Width of the Chart According to the Amount of Data you have

            let dataBars = <YOUR DATA OBJECTS>
            let realBarWidth = 20.0
            // Chart Width:
            let fullWidth = CGFloat(realBarWidth*Double(dataBars.count))
            layoutBarChartWidth.constant = max(fullWidth, view.frame.size.width)

Hope this Helps :-)

[zykis]

Thanks, @hernanarber !
I'll try it this evening, but still got some quesitons:
1) I can't find barWidth property in BarChartDataSet class. Even inspecting IBarChartDataSet.swift file shows only "barBorderWidth", "barBorderColor" etc. May be it was removed from new API?
2) I did declare IBOutlets of different UI objects in my Storyboard, but as for NSLayoutConstraint. How it can be actually ctrl-dragged from Storyboard, if it's not an UIView inheritor? I mean, if i ctrl-drag any point of BarChartView, IB will suggest me to create BarChartView outlet only

[hernanarber]

The .barWidth Property is not part of the ChartDataSet, but of the BarChartData :-)
let chartData = BarChartData(dataSet: chartDataSet)
Try it

[hernanarber]

For the constraint Go to the EXPLORER in the Storyboard so you can Ctrl+Drag the Constraint

[zykis]

@hernanarber oh, man!
Thank you a lot!!
I'll try this solution today

[aelam]

setting the visible range is what you want
checkout the BarLineChartViewBase.swift

     open func setVisibleXRange(minXRange: Double, maxXRange: Double)

[zykis]

@aelam Oh, thanks! I'll try that.
Though this method internally evaluating minScale and maxScale for viewportHandler.
I think the best way to handle this behavior is to understand, where these values (barWidth) are evaluating.

[hernanarber]

@aelam Can you explain me more about this?

I think this is what we need....

Thanks :-)

[zykis]

@hernanarber
/// Limits the maximum and minimum value count that can be visible by pinching and zooming. /// /// e.g. minRange=10, maxRange=100 no less than 10 values and no more that 100 values can be viewed /// at once without scrolling. /// /// If you call this method, chart must have data or it has no effect. open func setVisibleXRange(minXRange: Double, maxXRange: Double) { let minScale = _xAxis.axisRange / maxXRange let maxScale = _xAxis.axisRange / minXRange _viewPortHandler.setMinMaxScaleX( minScaleX: CGFloat(minScale), maxScaleX: CGFloat(maxScale)) }

That's what source tells us

[liuxuan30]

can be closed now

[zykis]

Well, BarChartData.barWidth not helps here.
Manipulations with setXVisibleRange can't change situation neither. I believe, it's connected with huge timestamps x-values. Any idea, where it's calculated in sources?
Timestamps are used since 1970

[liuxuan30]

Played with ChartsDemo, it's working:

        BarChartData *data = [[BarChartData alloc] initWithDataSets:dataSets];
        [data setValueFont:[UIFont fontWithName:@"HelveticaNeue-Light" size:10.f]];

        data.barWidth = 1.0f;

        _chartView.data = data;

[zykis]

You have a full-width entity just because your X-axis width is equal to 1.0. Just a coincidence.
The thing is ChartBarData.barWidth is POINT-BASED value, where X-axis width = [dataSet xMax] - [dataSet xMin]. You can test it out by setting entities values with e1(x=0, y=1) and e2(x=1000,y=0.7) and barWidth = 1;

[aelam]

@zykis
I don't think it's a good solution,
The bar width is a percentage,
What you need to do is handle the visible range of xAxis.
For example,
If xAxis visible range is 0,100, and bar width is 0.8
Then AN entry full pixel width is chartWidth / 100 , and the bar pixel width is chartWidth /100 * barWidth.

I don't think it's good that you change the barWidth dynamically. The dataSet part once is set, then done. Then take care of the view. The view handles how wide a full bar width is. To approach that, set an appropriate visibleRange.

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在 2017年5月6日，上午6:36，zykis [e-mail] 写道：

You have a full-width entity just because your X-axis width is equal to 1.0. Just a coincidence.
The thing is ChartBarData.barWidth is POINT-BASED value, where X-axis width = [dataSet xMax] - [dataSet xMin]. You can test it out by setting entities values with e1(x=0, y=1) and e2(x=1000,y=0.7) and barWidth = 1;

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[aelam]

I think you have got two issues,
One is get the bar wider,
One is get bar narrow .

If you you want the bar narrow. You can try set the barWidth = 0 , and borderwidth = 3

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在 2017年5月4日，上午4:34，zykis [e-mail] 写道：

Any way i can prevent bar width to be wider?

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[hernanarber]

I Tried Setting the Visible Range:
barChartView.setVisibleXRange(minXRange: 0.0, maxXRange: 5.0)

But as a Result the BarWidth is Changing depending on the amount of bars, What I Wanted was a CONSTANT Bar Width regardless of how much data was on the Chart :-(

[zykis]

@aelam
Well, actually the bar width is not in PERCENTAGES, but in POINTS.
BarChartRenderer.swift:71 prepareBuffer()

let barWidthHalf = barData.barWidth / 2.0
let left = CGFloat(x - barWidthHalf)
let right = CGFloat(x + barWidthHalf)
barRect.origin.x = left
barRect.size.width = right - left
barRect.origin.y = top
barRect.size.height = bottom - top

CGRect is sizing elements in points, not in percentages. So it's just a misleading.

But since renderer calculating left and right as mentioned above, now i have first and last bars cutted half:

Guess, i need to dig into viewport offsets and set them equal or more, then the half of the bar width

[billylo1]

I ran into the exact same issue with first/last bar cutted in half and barWidth problems (I also have timeIntervalSince1970 as xValues.)

Eventually got what my desired effect by storing # of days since the first bar as xValues; and use my custom formatter to translate xValue back to a String.

Hope this helps.

[aelam]

@zykis set the xAxisMin to -0.5 if you current minXValue is 0, then it wouldn't be cut, same as maxValue
and the unit of these -0.5, 0 , 0.5 are based on point not pixel, I said percentage before. But now I think you know what I mean now.

[aelam]

@zykis maybe you can try to keep every POINT in same pixels each time, then you can have a constant result that's what I meant

[zykis]

@billylo1 That's a nice point. I need to cut off some decades from my start value for sure :D
double ti = [date timeIntervalSince1970];
@aelam It worked fine for me. But i can't remember, when this solution was broken and by what circumstances.
My final solution fixed problem, by manipulating values of the bar:

BarChartData* data = [[BarChartData alloc] initWithDataSet:dataSet];

double xMin = [dataSet xMin]; // seconds since 1970x
double xMax = [dataSet xMax]; // seconds since 1970 + few days
double w = MAX(1, xMax - xMin); // if we have 7 days in xaxis, then its 7 * 24 * 60 * 60
double spacing = 0.05; // 5% of barWidth
double barWidth = w / [dataSet values].count - (spacing * w / ([dataSet values].count + 1)); // actual bar width
data.barWidth = barWidth;
[_chartView setFitBars:YES];

xaxis.spaceMin = barWidth / 10.0;
xaxis.spaceMax = barWidth / 10
xaxis.xOffset = barWidth;

_chartView.data = data;