html2canvas中图表的双重标题

Question

Html2canvas真的很酷但是：

该功能简单＆＃34;：

$scope.generateScreenshot = function () {
    html2canvas($("#screen-shot"), {
        onrendered: function(canvas) {
            // canvas is the final rendered <canvas> element
            var myImage = canvas.toDataURL("image/png");
            window.open(myImage);
        }
    });
}

为什么渲染标题存在问题？