图表转图片

$("#download").click(function() {
    var svg = $('svg')[0];
    var svg_xml = (new XMLSerializer).serializeToString(svg);
    var base64 = btoa(unescape(encodeURIComponent(svg_xml)));
    var data_uri = "data:image/svg+xml;base64," + base64;

    var image = new Image;
    image.src = data_uri;
    image.onload = function(){
        var canvas = document.createElement("canvas");
        canvas.width = image.width;
        canvas.height = image.height;

        var context = canvas.getContext("2d");
        context.clearRect(0, 0, image.width, image.height);
        context.drawImage(image, 0, 0);

        var title = $.trim($('input[name=title]').val());
        if(title.length == 0){
            title = 'charts_udpwork_com';
        }
        var a = document.createElement("a");
        a.download = title + ".png";
        a.href = canvas.toDataURL("image/png");
        a.target = '_blank';
        a.click();
   };
});