Selection-Tool plugin & Selection API

In light of a new build (v2.5.1) being released today, we have a new feature that deserves a post of its own. We have released the selection tool. This module will allow you to drag and highlight nodes on your chart. Because it's a module, it won't take up any KB on your page unless you are using it. Let's get to why you came here and tell you how it all works.

How To Include The Module

There are two ways to include the module:

1. You must first point the MODULES directory path, in the zingchart global object, to the appropriate modules folder.

<script src="cdn.zingchart.com/zingchart.min.js"></script>
<script> zingchart.MODULESDIR = "https://cdn.zingchart.com/modules/";</script>

Load the module using zingchart.loadModules([],fnc). The callback function will be executed upon the script request arriving.

// Load the selection-tool and render the chart once it's loaded
zingchart.loadModules('selection-tool', function() {
    zingchart.render({
        id : 'myChart',
        data : myConfig,
        height: 400,
        width: '100%',
        modules:'selection-tool'
    });
});

2. The alternative is to include the script tag directly in the DOM.

<script src= "cdn.zingchart.com/zingchart.min.js"></script>
<script src= "cdn.zingchart.com/modules/zingchart-selection-tool.min.js"></script>

How To Select Nodes

If you don't know much about selecting nodes in ZingChart, you should probably read up on the selected-state attribute first. You must apply some sort of selection styling to your chart for the selection tool to work.

For bar charts, you would style something similar to this:

plot: {
  selectedState: {
    backgroundColor: 'red'
  }
}

For line charts, you would style something similar to this:

plot: {
  selectedState: {
    lineColor: 'red'
  },
  selectedMarker: { // for line marker (nodes)
    backgroundColor: 'red'
  }
}

• Click + Drag to create rectangular selections
• (Ctrl/Cmnd) + (Click & Drag) to create free form selections.

Styling

You can style the mask of the selection area itself with the following attributes.

selectionTool: {
  mask: {
    borderWidth: 2,
    borderColor: "red", // works for (ctrl/cmnd + click) line color
    backgroundColor: "yellow",
    alpha: 0.5
  }
}

Other Attributes

If you don't want to include a certain plot in your selection tool, use the data-ignore-selection attribute on that plot.

{
  values: ...
  dataIgnoreSelection: true // 'data-ignore-selection'
}

Hello World Demo

How To Use The API

You must register the following code to receive the callback:

zingchart.bind('myChart', 'zingchart.plugins.selection-tool.selection', function(e) {
  ...
});

The API callback parameter e returns the following object:

{
  ev:MouseEvent
  graphid:"myChart-graph-id0"
  id:"myChart"
  nodes:Array[115] // selected node objects
  plotarea:true
  selection:Array[2] // selected noded indices by plot
  target:"none"
  targetid:"myChart-text-top"
  touch:false
  x:957
  y:248
}

1) Display Selected Values

You can use this information to display say, minValue, maxValue, sumtotal etc., to your users.

• demo

2) Change Tooltip

Additionally, the tooltip of the selected nodes can be changed to display various information. The appropriate syntax is:

tooltip:{
  selectedState:{
    text: series1Text
  }
}

In the following example, I aggregate each plot to display the sum of all values selected in that plot.

• demo

3) Selection Drilldown

You can display a new chart based on the data you have selected from your current chart. I'm using the zingchart API to update values on the second chart.

// update the second chart
zingchart.exec('selectionChart', 'setseriesdata', {
  data: newSeriesData
});

4) Render A Grid

You can even render a grid based on the selection you have made. In this example, I created a bootstrap table based on this documentation.

How To Clear Selection

It's very easy. Make a call to the clearselection API method. Now let's incorporate this into the chart by adding the function to the context menu. Let's create a place to store our function. Typically, it is not recommended to modify the zingchart object. This is for advanced users. It is good practice to keep all your charting stuff together, in this case your custom functions within the zingchart object! This will also help with name collisions within the window object.

BE WARNED: you can overwrite stuff in the zingchart object if you are
not careful. This will mess stuff up.

zingchart.insert_company_name_customFncs = {};
zingchart.insert_company_name_customFncs.clearSelection = function(e) {
  zingchart.exec(e.id,'clearselection');
}
 
// Load the selection-tool and render the chart once the module is loaded
zingchart.loadModules('selection-tool', function() {
    zingchart.render({
        id : 'myChart',
        // defined data this way since context menu needs to be defined in root (above graphset)
        data : { 
          gui:{
            contextMenu:{
              customItems: [
                {
                  text: 'Clear Selection',
                  function: 'zingchart.insert_company_name_customFncs.clearSelection()',
                  id: 'clearSelection'
                }
              ]
            }
          },
          graphset:[myConfig]
        },
        height: 400,
        width: '100%',
        modules:'selection-tool'
    });
});

• demo

Chart Types

The selection tool makes a lot of sense for scatter plots, but let's see it in action on a couple other chart types to convince you this plugin works on almost all charts.

Bar Chart

• demo

Radar Chart

• demo

Mixed Chart

If you don't want to include a certain plot in your selection, use the data-ignore-selection attribute on that plot.

• demo