Highcharts - Heatmap - Legend remove white "dashes"

Question

I need to remove all of these white lines from the heatmap legend. Does anyone know how I can edit these?

Rendered Chart

Design I'm trying to achieve

Answer 1

You can make it with gridLineColor: 'transparent' option:

colorAxis: {
    min: 0,
    minColor: '#FFFFFF',
    gridLineColor: 'transparent', // <== !!!
    maxColor: Highcharts.getOptions().colors[0]
},

Check the demo below:

function getPointCategoryName(point, dimension) {
    var series = point.series,
        isY = dimension === 'y',
        axis = series[isY ? 'yAxis' : 'xAxis'];
    return axis.categories[point[isY ? 'y' : 'x']];
}

Highcharts.chart('container', {

    chart: {
        type: 'heatmap',
        marginTop: 40,
        marginBottom: 80,
        plotBorderWidth: 1
    },


    title: {
        text: 'Sales per employee per weekday'
    },

    xAxis: {
        categories: ['Alexander', 'Marie', 'Maximilian', 'Sophia', 'Lukas', 'Maria', 'Leon', 'Anna', 'Tim', 'Laura']
    },

    yAxis: {
        categories: ['Monday', 'Tuesday', 'Wednesday', 'Thursday', 'Friday'],
        title: null,
        reversed: true
    },

    accessibility: {
        point: {
            descriptionFormatter: function (point) {
                var ix = point.index + 1,
                    xName = getPointCategoryName(point, 'x'),
                    yName = getPointCategoryName(point, 'y'),
                    val = point.value;
                return ix + '. ' + xName + ' sales ' + yName + ', ' + val + '.';
            }
        }
    },

    colorAxis: {
        min: 0,
        minColor: '#FFFFFF',
        gridLineColor: 'transparent',
        maxColor: Highcharts.getOptions().colors[0]
    },

    legend: {
        align: 'right',
        layout: 'vertical',
        margin: 0,
        verticalAlign: 'top',
        y: 25,
        symbolHeight: 280
    },

    tooltip: {
        formatter: function () {
            return '<b>' + getPointCategoryName(this.point, 'x') + '</b> sold <br><b>' +
                this.point.value + '</b> items on <br><b>' + getPointCategoryName(this.point, 'y') + '</b>';
        }
    },

    series: [{
        name: 'Sales per employee',
        borderWidth: 1,
        data: [[0, 0, 10], [0, 1, 19], [0, 2, 8], [0, 3, 24], [0, 4, 67], [1, 0, 92], [1, 1, 58], [1, 2, 78], [1, 3, 117], [1, 4, 48], [2, 0, 35], [2, 1, 15], [2, 2, 123], [2, 3, 64], [2, 4, 52], [3, 0, 72], [3, 1, 132], [3, 2, 114], [3, 3, 19], [3, 4, 16], [4, 0, 38], [4, 1, 5], [4, 2, 8], [4, 3, 117], [4, 4, 115], [5, 0, 88], [5, 1, 32], [5, 2, 12], [5, 3, 6], [5, 4, 120], [6, 0, 13], [6, 1, 44], [6, 2, 88], [6, 3, 98], [6, 4, 96], [7, 0, 31], [7, 1, 1], [7, 2, 82], [7, 3, 32], [7, 4, 30], [8, 0, 85], [8, 1, 97], [8, 2, 123], [8, 3, 64], [8, 4, 84], [9, 0, 47], [9, 1, 114], [9, 2, 31], [9, 3, 48], [9, 4, 91]],
        dataLabels: {
            enabled: true,
            color: '#000000'
        }
    }],

    responsive: {
        rules: [{
            condition: {
                maxWidth: 500
            },
            chartOptions: {
                yAxis: {
                    labels: {
                        formatter: function () {
                            return this.value.charAt(0);
                        }
                    }
                }
            }
        }]
    }

});

.highcharts-figure, .highcharts-data-table table {
    min-width: 360px; 
    max-width: 800px;
    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;
}

<script src="https://code.highcharts.com/highcharts.js"></script>
<script src="https://code.highcharts.com/modules/heatmap.js"></script>
<script src="https://code.highcharts.com/modules/exporting.js"></script>
<script src="https://code.highcharts.com/modules/export-data.js"></script>
<script src="https://code.highcharts.com/modules/accessibility.js"></script>

<figure class="highcharts-figure">
    <div id="container"></div>
    <p class="highcharts-description">
        Heatmap showing employee data per weekday. Heatmaps are commonly used to
        visualize hot spots within data sets, and to show patterns or correlations.
        Due to their compact nature, they are often used with large sets of data.
    </p>
</figure>