自定义Jquery Sparkline条形图的CSS

Question

我想让我的jquery迷你图条形图中的条形四舍五入。如何使条形半径变圆？

$("#tophistorytest").sparkline([$scope.barCort1,$scope.barCort2,$scope.barCort3,$scope.barCort4,$scope.barCort5,$scope.barCort6,$scope.barCort7], {
        type: 'bar',
        width: '100%',
        height: '145',
        barColor: '#ff6600',
        fillColor: '#fff',
        barWidth: 25,
        spotColor: undefined,
        minSpotColor: undefined,
        maxSpotColor: undefined,
        highlightSpotColor: undefined,
        highlightLineColor: undefined,
        barSpacing: 4,
        chartRangeMin :0,
        spotColor: '#ff6600',
        minSpotColor: '#ff6600',
        maxSpotColor: '#ff6600',
    });  



<div id="sparkline"></div>