Area chart

Version: 5.8

(quoted from Area chart definition in Wikipedia)

A area chart displays graphically quantitative data. It is based on the area chart. The area between axis and area are commonly emphasized with colors, textures and hatchings. Commonly one compares two or more quantities with an area chart.

Programmatically, you could use a area chart as following:

// creates the chart    
AreaChart chart = new AreaChart();
// adds to DOM
component.add(chart);
...
// example for Elemental2
// gets the chart instance as DOM element
Element element = chart.getChartElement().as();
// adds to DOM
DomGlobal.document.body.appendChild(element);

By UIBinder (ONLY for GWT), you could use a area chart as following:

<ui:UiBinder xmlns:ui="urn:ui:com.google.gwt.uibinder"
   xmlns:g="urn:import:com.google.gwt.user.client.ui"
   xmlns:c="urn:import:org.pepstock.charba.client.gwt.widgets">

   <g:HTMLPanel  width="100%">
      ....
      <c:AreaChartWidget ui:field="chart"/>
      ...
   </g:HTMLPanel>
</ui:UiBinder> 

Dataset

The area chart allows to define the data and a number of properties, used to display the data, by a area dataset.

Every chart has got a method to create a typed dataset accordingly with the chart type. The dataset can be also created instantiating the constructor.

// creates the chart
AreaChart chart = new AreaChart();
// creates the dataset
AreaDataset dataset = chart.newDataset();
// sets the option
dataset.setBackgroundColor(HtmlColor.RED);
...
// creates the dataset
AreaDataset datasetNew = new AreaDataset();
// sets the option
datasetNew.setBackgroundColor(HtmlColor.RED);
...
// sets the datasets to the chart
chart.getData().setDatasets(dataset, datasetNew);

The following are the attributes that you can set:

Name	Type	Scriptable	Description
backgroundColor	String - IsColor - Pattern - Gradient	Yes	The fill color/pattern under the area.
borderCapStyle	CapStyle	Yes	Cap style of the area. See MDN.
borderColor	String - IsColor - Gradient	Yes	The color of the area.
borderDash	int[]	Yes	Length and spacing of dashes. See MDN.
borderDashOffset	double	Yes	Offset for area dashes. See MDN.
borderJoinStyle	JoinStyle	Yes	Area joint style. See MDN.
borderWidth	int	Yes	The width of the area in pixels.
cubicInterpolationMode	CubicInterpolationMode	Yes	Algorithm used to interpolate a smooth curve from the discrete data points.
clip	boolean - double - Clip	-	How to clip relative to chart area. Positive value allows overflow, negative value clips that many pixels inside chart area.
drawActiveElementsOnTop	boolean	Yes	Draw the active points of a dataset over the other points of the dataset.
hoverBackgroundColor	String - IsColor - Pattern - Gradient	Yes	The fill color/pattern under the area, when hovered.
hoverBorderCapStyle	CapStyle	Yes	Cap style of the area, when hovered. See MDN.
hoverBorderColor	String - IsColor - Gradient	Yes	The color of the area, when hovered.
hoverBorderDash	int[]	Yes	Length and spacing of dashes, when hovered. See MDN.
hoverBorderDashOffset	int	Yes	Offset for area dashes, when hovered. See MDN.
hoverBorderJoinStyle	JoinStyle	Yes	Area joint style, when hovered. See MDN.
hoverBorderWidth	int	Yes	The width of the area in pixels, when hovered.
indexAxis	IndexAxis	-	The base axis of the dataset. 'IndexAxis.X' for horizontal areas and 'IndexAxis.Y' for vertical areas.
label	String	-	The label for the dataset which appears in the legend and tooltips.
normalized	boolean	-	If `true`, you provide data with indices that are unique, sorted, and consistent across data sets and provide the normalized.
order	int	-	The drawing order of dataset. Also affects order for stacking, tooltip, and legend.
parsing	boolean	-	If `false`, the data set parsing is disable. If parsing is disabled, data must be sorted and in the formats the associated chart type and scales use internally.
pointBackgroundColor	String[] - IsColor[] - Gradient[]	Yes	The fill color for points.
pointBorderColor	String[] - IsColor[] - Gradient[]	Yes	The border color for points.
pointBorderWidth	int[]	Yes	The width of the point border in pixels.
pointHitRadius	double[]	Yes	The pixel size of the non-displayed point that reacts to mouse events.
pointHoverBackgroundColor	String[] - IsColor[] - Gradient[]	Yes	Point background color when hovered.
pointHoverBorderColor	String[] - IsColor[] - Gradient[]	Yes	Point border color when hovered.
pointHoverBorderWidth	int[]	Yes	Border width of point when hovered.
pointHoverRadius	double[]	Yes	The radius of the point when hovered.
pointRadius	double[]	Yes	The radius of the point shape. If set to 0, the point is not rendered.
pointRotation	double[]	Yes	The rotation of the point in degrees.
pointStyle	PointStyle[] - Img[] - Canvas[]	Yes	Style of the point.
showArea	boolean	-	If `false`, the area is not drawn for this dataset.
spanGaps	boolean - double	-	If `true`, areas will be drawn between points with no or null data. If `false`, points with `NaN` data will create a break in the area. Can also be a number specifying the maximum gap length to span. The unit of the value depends on the scale used.
stepped	boolean - Stepped	Yes	If the area is shown as a stepped area.
tension	double	-	Bezier curve tension of the area. Set to 0 to draw straight areas. This option is ignored if monotone cubic interpolation is used.
xAxisID	String	-	The ID of the x axis to plot this dataset on.
yAxisID	String	-	The ID of the y axis to plot this dataset on.

General

The general options for a area dataset can control behaviors not related to styling or interactions and they are the following:

Name	Defaults	Description
clip	Undefined.DOUBLE	How to clip relative to chart area.
drawActiveElementsOnTop	`true`	Draw the active points of a dataset over the other points of the dataset.
indexAxis	IndexAxis.X	The base axis of the dataset.
label	`null`	The label for the dataset which appears in the legend and tooltips.
normalized	`false`	If `true`, you provide data with indices that are unique, sorted, and consistent across data sets and provide the normalized.
order	0	The drawing order of dataset. Also affects order for stacking, tooltip, and legend.
parsing	`true`	If `false`, the data set parsing is disable. If parsing is disabled, data must be sorted and in the formats the associated chart type and scales use internally.
xAxisID	DefaultScaleId.X	The ID of the x axis to plot this dataset on.
yAxisID	DefaultScaleId.Y	The ID of the y axis to plot this dataset on.

Point styling

The style of each point of the dataset can be configured by the following properties:

Name	Description
pointBackgroundColor	The fill color for points.
pointBorderColor	The border color for points.
pointBorderWidth	The width of the point border in pixels.
pointHitRadius	The pixel size of the non-displayed point that reacts to mouse events.
pointRadius	The radius of the point shape.
pointRotation	The rotation of the point in degrees.
pointStyle	Style of the point.

All above options have got the fallback to the associated Point elements, retrievable by the following statements:

// from chart instance
Point point = chart.getOptions().getElements().getPoint();
// sets options for all area datasets of the chart
point.setRadius(6);
...
// from defaults
Point defaultPoint  = Defaults.get().getGlobal().getElements().getPoint();
// sets options for all area datasets of all charts
defaultPoint.setRadius(6);

Area styling

The style of each area of the dataset can be configured by the following properties:

Name	Description
backgroundColor	The fill color under the area.
borderCapStyle	Cap style of the area.
borderColor	The color of the area.
borderDash	Length and spacing of dashes.
borderDashOffset	Offset for area dashes.
borderJoinStyle	Area joint style
borderWidth	The width of the area in pixels.
cubicInterpolationMode	Algorithm used to interpolate a smooth curve from the discrete data points.
stepped	If the area is shown as a stepped area.
tension	Bezier curve tension of the area.

All above options have got the fallback to the associated Area elements, retrievable by the following statements:

// from chart instance
Area area = chart.getOptions().getElements().getArea();
// sets options for all area datasets of the chart
area.setBorderWidth(6);
...
// from defaults
Area defaultArea  = Defaults.get().getGlobal().getElements().getArea();
// sets options for all area datasets of all charts
defaultArea.setBorderWidth(6);

Point interactions

The interaction with each point can be controlled with the following properties:

Name	Description
pointHoverBackgroundColor	Point background color when hovered.
pointHoverBorderColor	Point border color when hovered.
pointHoverBorderWidth	Border width of point when hovered.
pointHoverRadius	The radius of the point when hovered.

All above options have got the fallback to the associated Point elements, retrievable by the following statements:

// from chart instance
Point point = chart.getOptions().getElements().getPoint();
// sets options for all area datasets of the chart
point.setRadius(6);
...
// from defaults
Point defaultPoint  = Defaults.get().getGlobal().getElements().getPoint();
// sets options for all area datasets of all charts
defaultPoint.setRadius(6);

Area interactions

The interaction with each area can be controlled with the following properties:

Name	Description
hoverBackgroundColor	The fill color under the area, when hovered.
hoverBorderCapStyle	Cap style of the area, when hovered.
hoverBorderColor	The color of the area, when hovered.
hoverBorderDash	Length and spacing of dashes, when hovered.
hoverBorderDashOffset	Offset for area dashes, when hovered.
hoverBorderJoinStyle	Area joint style, when hovered.
hoverBorderWidth	The width of the area in pixels, when hovered.

All above options have got the fallback to the associated Area elements, retrievable by the following statements:

// from chart instance
Area area = chart.getOptions().getElements().getArea();
// sets options for all area datasets of the chart
area.setBorderWidth(6);
...
// from defaults
Area defaultArea  = Defaults.get().getGlobal().getElements().getArea();
// sets options for all area datasets of all charts
defaultArea.setBorderWidth(6);

Scriptable

Scriptable options at dataset level accept a callback which is called for each of the underlying data values. See more details in Configuring charts section.

// creates chart
AreaChart chart = new AreaChart();
// creates dataset
AreaDataset dataset = chart.newDataset();
// sets the option by a callback 
dataset.setBackgroundColor(new ColorCallback<DatasetContext>(){

   @Override
   public IsColor invoke(DatasetContext context){
      // logic
      return color;
   }
});

The following options can be set by a callback:

Name	Callback	Returned types
backgroundColor	ColorCallback<DatasetContext>	String - IsColor - Pattern - Gradient
borderCapStyle	CapStyleCallback<DatasetContext>	CapStyle
borderColor	ColorCallback<DatasetContext>	String - IsColor - Gradient
borderDash	BorderDashCallback<DatasetContext>	List<Integer>
borderDashOffset	BorderDashOffsetCallback<DatasetContext>	double
borderJoinStyle	JoinStyleCallback<DatasetContext>	JoinStyle
borderWidth	WidthCallback<DatasetContext>	int
cubicInterpolationMode	CubicInterpolationModeCallback	CubicInterpolationMode
drawActiveElementsOnTop	DrawActiveElementsOnTopCallback	boolean
hoverBackgroundColor	ColorCallback<DatasetContext>	String - IsColor - Pattern - Gradient
hoverBorderCapStyle	CapStyleCallback<DatasetContext>	CapStyle
hoverBorderColor	ColorCallback<DatasetContext>	String - IsColor - Gradient
hoverBorderDash	BorderDashCallback<DatasetContext>	List<Integer>
hoverBorderDashOffset	BorderDashOffsetCallback<DatasetContext>	int
hoverBorderJoinStyle	JoinStyleCallback<DatasetContext>	JoinStyle
hoverBorderWidth	WidthCallback<DatasetContext>	int
pointBackgroundColor	ColorCallback<DatasetContext>	String - IsColor - Gradient
pointBorderColor	ColorCallback<DatasetContext>	String - IsColor - Gradient
pointBorderWidth	WidthCallback<DatasetContext>	int
pointHitRadius	RadiusCallback<DatasetContext>	double
pointHoverBackgroundColor	ColorCallback<DatasetContext>	String - IsColor - Gradient
pointHoverBorderColor	ColorCallback<DatasetContext>	String - IsColor - Gradient
pointHoverBorderWidth	WidthCallback<DatasetContext>	int
pointHoverRadius	RadiusCallback<DatasetContext>	double
pointRadius	RadiusCallback<DatasetContext>	double
pointRotation	RotationCallback<DatasetContext>	double
pointStyle	PointStyleCallback<DatasetContext>	PointStyle - Img - Canvas
stepped	SteppedCallback	Stepped

Data structure

When the data is an array or list of doubles, the x axis is generally a category. The points are placed onto the axis using their position in the array. When a area chart is created with a category axis, the labels property of the data object must be specified.

// sets data as an array of doubles
dataset.setData(1,2,3,4,6);

// sets data as a list of double
List<Double> list = new LinkedList<>();
list.add(1);
list.add(2);
list.add(3);
dataset.setData(list);

Options

The area chart defines specific options implementation to be configured. These options are merged with the global chart configuration options to form the options passed to the chart.

// creates chart
AreaChart chart = new AreaChart();
// gets the chart options
AreaOptions options = chart.getOptions();
// sets options
options.setResponsive(true);
options.setShowLine(false);

These are the options specific to area charts:

Name	Type	Default	Description
showLine	boolean	`true`	If `false`, the lines between points are not drawn.
spanGaps	boolean - double	`false`	If `true`, areas will be drawn between points with no or null data. If `false`, points with `NaN` data will create a break in the area. Can also be a number specifying the maximum gap length to span. The unit of the value depends on the scale used.

Area chart​

Dataset​

General​

Point styling​

Area styling​

Point interactions​

Area interactions​

Scriptable​

Data structure​

Options​