Nevron Open Vision Documentation
Bar Series

Bar charts display a sequence of horizontal or vertical bars of lengths proportional to the value that they represent. Bar charts are used to compare two or more values. The following image shows a typical bar and cluster bar charts:

Creating a Bar Series

Bar series are represented by the NBarSeries type. An instance of this type must be added to the series collection of a Cartesian chart:

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NBarSeries bar = new NBarSeries();

chart.Series.Add(bar);

Passing Data

Bar series accept data points of type NBarDataPoint. The following code snippet shows how to add several data points to a bar series:

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bar.DataPoints.Add(new NBarDataPoint(10));

bar.DataPoints.Add(new NBarDataPoint(20));

bar.DataPoints.Add(new NBarDataPoint(30));

Controlling the bars origin

By default the bars use 0 as origin. You can modify this behavior by setting the OriginMode property. The following table lists the available options:

ENSeriesOriginMode Description
CustomOrigin The series origin value is specified by the Origin property.
MinValue The series min value is used as a series origin.
MaxValue The series max value is used as a series origin.
ScaleMin The min scale value is used as a series origin.
ScaleMax The max scale value is used as a series origin.

 

 The following code snippet changes the area origin to 10:

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bar.OriginMode = ENSeriesOriginMode.CustomOrigin;

bar.CustomOrigin = 10;

Controlling the bars width

The width of the bars in the bar series is controlled from the WidthMode property accepting values from the ENBarWidthMode enum. The following table lists the available options:

ENBarWidthMode Description
FixedWidth The width of the bar is fixed to the value of Width property specified in dips.
ScaleWidth The width of the bar is computed as the scaled value of the Width property.
MinGap The width of the bar is dynamically computed based on the smallest distance between two adjacent bars multipled by (1 - GapFactor).

Following are some examples showing how to modify the bar width:

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// bar width is 20 dips

bar.WidthMode = ENBarWidthMode.FixedWidth;

bar.Width = 20;

// bar width is 1 category unit

bar.WidthMode = ENBarWidthMode.ScaleWidth;

bar.Width = 1;

// bar width is 50 of the minimum gap between two adjacent bars

bar.WidthMode = ENBarWidthMode.MinGap;

bar.GapFactor = 0.5;

 

Creating a Stacked Bar Chart

A stacked bar chart displays several series stacked so that there is a single column for each category. The height of each column is determined by the total of all series values for the category. Stacked bar charts are displayed with several NBarSeries objects. The MultiBarMode property of the first bar series must be set to ENMultiBarMode.Series. The MultiBarMode property of the subsequent bar series must be set to ENMultiBarMode.Stacked or ENMultiBarMode.StackedPercent. The following example demonstrates how to create a stack bar chart with two stacks:

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NBarSeries bar1 = new NBarSeries();

NBarSeries bar2 = new NBarSeries();

bar1.MultiBarMode = ENMultiBarMode.Series;

bar2.MultiBarMode = ENMultiBarMode.Stacked;

When a bar series is stacked it is always displayed with origin 0.

Stacked bar charts support negative values, which means that if you insert negative values in the Values data series the respective stacks will be piled below the zero. In this case since the values for a certain category can be both positive and negative the chart will display two piles for each category - one for the positive values which grows above the zero and another one for the negative values which grows below the zero.

Creating a Cluster Bar Chart

Cluster Bar charts are composed of several bar series. The data points from the same category are displayed side-by-side, forming "clusters" along the X axis. This representation is convenient when you need to compare the Y values for a given category or X value. Cluster bar charts are displayed with several NBarSeries or objects. The MultiBarMode property of the first bar series must be set to ENMultiBarMode.Series. For the subsequent series the MultiBarMode property must be set to ENMultiBarMode.Clustered. The following example demonstrates how to a create cluster with two series:

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NBarSeries bar1 = new NBarSeries();

chart.Series.Add(bar1);

NBarSeries bar2 = new NBarSeries();

chart.Series.Add(bar2);

bar1.MultiBarMode = ENMultiBarMode.Series;

bar2.MultiBarMode = ENMultiBarMode.Clustered;

Creating a Cluster Stack Bar Chart

You can also create a cluster stack bar chart. In this case each bar series which must be part of a cluster must have the MultiBarMode property set to ENMultiBarMode.Cluster and each stacked bar series inside the cluster must have the MultiBarMode property set to ENMultiBarMode.Stacked:

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NBarSeries bar1 = new NBarSeries();

chart.Series.Add(bar1);

NBarSeries bar2 = new NBarSeries();

chart.Series.Add(bar2);

NBarSeries bar3 = new NBarSeries();

chart.Series.Add(bar3);

bar1.MultiBarMode = ENMultiBarMode.Series;

bar2.MultiBarMode = ENMultiBarMode.Clustered;

bar3.MultiBarMode = ENMultiBarMode.Stacked;

Palette

The bar series can have an associated palette, in which case the Fill properties of the series / data points is discarded. The following code snippet shows how to apply a palette filling:

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bar.Palette = new NTwoColorPalette(NColor.Red, NColor.Green);

Formatting Commands

The bar series supports the following formatting commands in addition to the standard (per data point) formatting commands:

<total> - displays the absolute sum of the values in the current stack.
<cumulative> - displays the sum of the values up to the current stack value.
<percent> - displays the percent contribution of the value to the total pile sum.

 

See Also

Charts

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