Google Chart: Labelling Stacked Column Charts

Question

Based on googleAPI documentation: https://developers.google.com/chart/interactive/docs/gallery/columnchart?hl=en

As you can see in "labeling columns" section each column is labeled with a static value. I want to know if it is possible to label a column with a specific value resulting of the sum of all.

// Set chart options
     var options = {

         width: 400,
         height: 300,
         calc:????
     };

Should i set this "calc" field with a specific function?

JSFIDDLE: Total Labeling Column

I can't figure out how can i customize a label with the sum values of each stacked column.

Answer 1

You can use getNumberOfRows(), getNumberOfColumns() and getValue() functions to calculate total and set that value instead of string total:

function drawChart() {
    // Create the data table.
    var data = new google.visualization.arrayToDataTable(array);

    for (var i = 0; i < data.getNumberOfRows(); i++) {
        var total = 0;

        for (var j = 1; j < data.getNumberOfColumns() - 2; j++) {
            // console.log(data.getValue(i, j));
            total += data.getValue(i, j);
        }
        data.setValue(i, data.getNumberOfColumns() - 1, '' + total);
    }
...

You will have to change or size of chart or size of fonts to get values properly displayed on columns. Labels are displayed correctly.