Accessible pie chart

author(s): Torstein Hønsi

by oysteinmoseng

HTML

<script src="https://code.highcharts.com/highcharts.js"></script>
<script src="https://code.highcharts.com/modules/accessibility.js"></script>
<script src="https://code.highcharts.com/modules/pattern-fill.js"></script>
<script src="https://code.highcharts.com/themes/high-contrast-light.js"></script>

<div id="chart-wrap">
    <label id="patterns-enabled-label">
      <input type="checkbox" id="patterns-enabled" checked>
    </label>

    <figure class="highcharts-figure">
        <div id="container"></div>
    </figure>
</div>

CSS

#patterns-enabled {
    width: 17px;
    height: 17px;
    vertical-align: middle;
    margin-top: 0;
    cursor: pointer;
}

#patterns-enabled-label {
    cursor: pointer;
}

#container {
    height: 420px;
}

#chart-wrap {
    min-width: 350px;
    max-width: 650px;
    margin: 1em auto;
    font-family: sans-serif;
}

.highcharts-figure,
.highcharts-data-table table {
    margin: 1em auto;
}

.highcharts-data-table table {
    font-family: Verdana, sans-serif;
    border-collapse: collapse;
    border: 1px solid #ebebeb;
    margin: 10px auto;
    text-align: center;
    width: 100%;
    max-width: 500px;
}

.highcharts-data-table caption {
    padding: 1em 0;
    font-size: 1.2em;
    color: #555;
}

.highcharts-data-table th {
    font-weight: 600;
    padding: 0.5em;
}

.highcharts-data-table td,
.highcharts-data-table th,
.highcharts-data-table caption {
    padding: 0.5em;
}

.highcharts-data-table thead tr,
.highcharts-data-table tr:nth-child(even) {
    background: #f8f8f8;
}

.highcharts-data-table tr:hover {
    background: #f1f7ff;
}

JavaScript

var clrs = Highcharts.getOptions().colors;
var pieColors = [clrs[2], clrs[0], clrs[3], clrs[1], clrs[4]];

// Get a default pattern, but using the pieColors above.
// The i-argument refers to which default pattern to use
function getPattern(i) {
    return {
        pattern: Highcharts.merge(Highcharts.patterns[i], {
            color: pieColors[i]
        })
    };
}

// Get 5 patterns
var patterns = [0, 1, 2, 3, 4].map(getPattern);

var chart = Highcharts.chart('container', {
    chart: {
        type: 'column'
    },

    title: {
        text: 'Primary desktop/laptop screen readers'
    },

    colors: patterns,

	plotOptions: {
    	column: {
	    	groupPadding: 0,
            pointWidth: 50
        }
    },

    series: [{
		name: 'NVDA',
        data: [{
            y: 40.6,
            website: 'https://www.nvaccess.org',
            accessibility: {
                description: 'This is the most used desktop screen reader'
            }
        }]
	    }, {
            name: 'JAWS',
            data: [40.1],
        }, {
            name: 'VoiceOver',
            data: [12.9],
        }, {
            name: 'ZoomText',
            data: [2],
        }, {
            name: 'Other',
            data: [4.4],
        }
    ]
});

// Toggle patterns enabled
document.getElementById('patterns-enabled').onclick = function () {
    chart.update({
        colors: this.checked ? patterns : pieColors
    });
};