You can add a header element as <div> and customize it to show the population of a particular country or continent on treemap drill-down.
To customize the header for treemap drill-down, follow the given steps:
Step 1:
Initialize the treemap and enable the drill-down option.
// Initialize the tree map control
var treemap = new ej.treemap.TreeMap({
palette: ['#9999ff', '#CCFF99', '#FFFF99', '#FF9999', '#FF99FF', '#FFCC66'],
enableDrillDown: true,
format: 'n',
useGroupingSeparator: true,
dataSource: DrillDown,
weightValuePath: 'Population',
tooltipSettings: {
visible: true,
format: '${Name} : ${Population}'
},
leafItemSettings: {
labelPath: 'Name',
showLabels: false,
labelStyle: { size: '0px' },
border: { color: 'black', width: 0.5 }
},
levels: [
{ groupPath: 'Continent', fill: '#336699', border: { color: 'black', width: 0.5 } },
{ groupPath: 'States', fill: '#336699', border: { color: 'black', width: 0.5 } },
{ groupPath: 'Region', showHeader: false, fill: '#336699', border: { color: 'black', width: 0.5 } },
],
});
// Render the initialized tree map
treemap.appendTo('#container');Step 2:
Show the population of a particular continent in the treemap loaded event. In this event, you can get the header element.
loaded: function (args) {
var header = document.getElementById('header');
var population = 0;
for (var i = 0; i < args.treemap.layout.renderItems[0]['parent'].Continent.length; i++) {
population += +(args.treemap.layout.renderItems[0]['parent'].Continent[i]['data'].Population);
}
header.innerHTML = 'Continent - Population : ' + population
}Step 3:
Customize the population for drilled countries or states in the header element when drill-down the treemap. The drillEnd event will be triggered when treemap is drilled.
var treemap = new ej.treemap.TreeeMap({
palette: ['#9999ff', '#CCFF99', '#FFFF99', '#FF9999', '#FF99FF', '#FFCC66'],
enableDrillDown: true,
format: 'n',
useGroupingSeparator: true,
dataSource: DrillDown,
weightValuePath: 'Population',
tooltipSettings: {
visible: true,
format: '${Name} : ${Population}'
},
leafItemSettings: {
labelPath: 'Name',
showLabels: false,
labelStyle: { size: '0px' },
border: { color: 'black', width: 0.5 }
},
levels: [
{ groupPath: 'Continent', fill: '#336699', border: { color: 'black', width: 0.5 } },
{ groupPath: 'States', fill: '#336699', border: { color: 'black', width: 0.5 } },
{ groupPath: 'Region', showHeader: false, fill: '#336699', border: { color: 'black', width: 0.5 } },
],
loaded: function (args) {
var header = document.getElementById('header');
var population = 0;
for (var i = 0; i < args.treemap.layout.renderItems[0]['parent'].Continent.length; i++) {
population += +(args.treemap.layout.renderItems[0]['parent'].Continent[i]['data'].Population);
}
header.innerHTML = 'Continent - Population : ' + population
},
drillEnd: function (args) {
var header = document.getElementById('header');
var layout = document.getElementById("container_TreeMap_Squarified_Layout");
var population = 0;
if (args.treemap.layout.renderItems[0]['isDrilled']) {
for (var i = 0; i < args.treemap.layout.renderItems.length; i++) {
population += +(args.treemap.layout.renderItems[i]['data'].Population);
}
header.innerHTML = layout.children[0].children[1].innerHTML.split(']')[1] + ' - ' + population;
}
else if (args.treemap.layout.renderItems[0]['parent'].Continent) {
for (var i = 0; i < args.treemap.layout.renderItems[0]['parent'].Continent.length; i++) {
population += +(args.treemap.layout.renderItems[0]['parent'].Continent[i]['data'].Population);
}
header.innerHTML = 'Continent - Population : ' + population;
} else {
population = args.treemap.layout.renderItems[0]['data'].Population;
header.innerHTML = layout.children[0].children[1].innerHTML.split(']')[1] + ' - Population : ' + population;
}
}
}, '#container');<!DOCTYPE html><html lang="en"><head>
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