code: function drawHorizontalLegend() {
              let xOffset = markerSize;
  
              svg.select('.legend-group')
                  .selectAll('g')
                  .remove();
  
              // We want a single line
              svg.select('.legend-group')
                .append('g')
                  .classed('legend-line', true);
  
              // And one entry per data item
              entries = svg.select('.legend-line')
                .selectAll('g.legend-entry')
                .data(data);
  
              // Enter
              entries.enter()
                .append('g')
                  .classed('legend-entry', true)
                  .attr('data-item', getId)
                  .attr('transform', function({name}) {
                      let horizontalOffset = xOffset,
                          lineHeight = chartHeight / 2,
                          verticalOffset = lineHeight,
                          labelWidth = textHelper.getTextWidth(name, textSize);
  
                      xOffset += markerSize + 2 * getLineElementMargin() + labelWidth;
  
                      return `translate(${horizontalOffset},${verticalOffset})`;
                  })
                  .merge(entries)
                .append('circle')
                  .classed('legend-circle', true)
                  .attr('cx', markerSize/2)
                  .attr('cy', markerYOffset)
                  .attr('r', markerSize / 2)
                  .style('fill', getCircleFill)
                  .style('stroke-width', 1);
  
              svg.select('.legend-group')
                  .selectAll('g.legend-entry')
                .append('text')
                  .classed('legend-entry-name', true)
                  .text(getName)
                  .attr('x', getLineElementMargin())
                  .style('font-size', `${textSize}px`)
                  .style('letter-spacing', `${textLetterSpacing}px`);
  
              // Exit
              svg.select('.legend-group')
                  .selectAll('g.legend-entry')
                  .exit()
                  .transition()
                  .style('opacity', 0)
                  .remove();
  
              adjustLines();
          }
docs: Draws the entries of the legend within a single line
  @private