User interaction in TypeScript Chart control

18 Nov 20184 minutes to read

Tooltip

Chart will display details about the points through tooltip, when the mouse is moved over the point.

Enable Tooltip for Data Point

By default, tooltip is not visible. Enable the tooltip by setting enable property to true and by injecting Tooltip module using Chart.Inject(Tooltip).

Format the Tooltip

By default, tooltip shows information of x and y value in points. In addition to that, you can show more information in tooltip. For example the format ${series.name} ${point.x} shows series name and point x value.

Tooltip Template

Any HTML elements can be displayed in the tooltip by using the ‘template’ property of the tooltip. You can use the ${x} and ${y} as place holders in the HTML element to display the x and y values of the corresponding data point.

Customize the Appearance of Tooltip

The fill and border properties are used to customize the background color and border of the tooltip respectively. The textStyle property in the tooltip is used to customize the font of the tooltip text.

Zooming and Panning

Enable Zooming

Chart can be zoomed in three ways.

  • Selection - By setting enableSelectionZooming property to true in zoomSettings, you can zoom the chart by using the rubber band selection.
  • Mousewheel - By setting enableMouseWheelZooming property to true in zoomSettings, you can zoomin and zoomout the chart by scrolling the mouse wheel.
  • Pinch - By setting enablePinchZooming property to true in zoomSettings, you can zoom the chart through pinch gesture in touch enabled devices.

Pinch zooming is supported only in browsers that support multi-touch gestures. Currently IE11, Chrome and Opera browsers support multi-touch in desktop devices.

After zooming the chart, a zooming toolbar will appear with zoom,zoomin, zoomout, pan and reset buttons. Selecting the Pan option will allow to pan the chart and selecting the Reset option will reset the zoomed chart.

Modes of Zooming

The mode property in zoomSettings specifies whether the chart is allowed to scale along the horizontal axis or vertical axis. The default value of the mode is XY (both axis).

There are three types of mode.

  • X- Allows us to zoom the chart horizontally.
  • Y - Allows us to zoom the chart vertically.
  • XY – Allows us to zoom the chart both vertically and horizontally.

Customizing Zooming Toolbar

By default, zoomin, zoomout, pan and reset buttons will be displayed for zoomed chart. You can customize to show your desire tools in the toolbar using toolbarItems property.

Note: To use zooming feature, we need to inject Zoom module Chart.Inject(Zoom) method.

Crosshair

Crosshair has a vertical and horizontal line to view the value of the axis at mouse or touch position.

Enable Crosshair

Crosshair lines can be enabled by using enable property in the crosshair. Likewise tooltip label for an axis can be enabled by using enable property of crosshairTooltip in the corresponding axis.

Customization

The fill and textStyle prop property of the crosshairTooltip is used to customize the background color and font style of the crosshair label respectively. Color and width of the crosshair line can be customized by using the line property in the crosshair.

Note: To use crosshair feature, we need to inject Crosshair module Chart.Inject(Crosshair) method.

Trackball

Trackball is used to track a data point closest to the mouse or touch position. Trackball marker indicates the closest point and trackball tooltip displays the information about the point. To use trackball feature, we need to inject Crosshair module and Tooltip module using
Chart.Inject(Crosshair, Tooltip).

Trackball can be enabled by setting the enable property of the crosshair to true and
shared property in tooltip to true in chart.

Selection

Chart provides selection support for the series and its data points on mouse click.

When Mouse is clicked on the data points, the corresponding series legend also will be selected.

We have different types of selection mode for selecting a data.

  • None
  • Point
  • Series
  • Cluster
  • DragXY
  • DragX
  • DragY

Point

You can select a point, by setting selectionMode to point.

Series

You can select a series, by setting selectionMode to series.

Cluster

You can select the points that corresponds to the same index in all the series, by setting selectionMode to cluster.

DragXY, DragX and DragY

To fetch a collection of data under a particular region, you have to set selectionMode as DragXY.

  • DragXY - Allow us to select data with respect to both horizontal and vertical axis.
  • DragX - Allow us to select data with respect to horizontal axis.
  • DragY - Allow us to select data with respect to vertical axis.

The selected data’s are returned as an array collection in the dragComplete event.

Selection Type

You can select multiple points or series, by enabling the isMultiSelect
property.

Customizing Selection Style

You can apply custom style to selected points or series with selectionStyle property.

Selection on Load

You can able to select a point or series programmatically on a chart using selectedDataIndexes property.