将 SVG 转换为 PNG 格式的图像

问题描述

我正在使用 html2canvas 和 canvg 插件将角度 nvd3 图表转换为 svg，但是当我将饼图转换为 png 时，我看起来与图表相同，但是当我转换折线图或面积图时，它的背景变为黑色，一些圆圈被淹没图片.我的代码是

i am converting angular nvd3 chart to svg using html2canvas and canvg plugings but when i convert pie chart to png then i looks same as chart but when i convert line chart or area chart then its background goes to black and some circle drown on image.My code is

var svgElements = $("#container").find('svg');

            //replace all svgs with a temp canvas
            svgElements.each(function () {
                var canvas, xml;

                // canvg doesn't cope very well with em font sizes so find the calculated size in pixels and replace it in the element.
                $.each($(this).find('[style*=em]'), function (index, el) {
                    $(this).css('font-size', getStyle(el, 'font-size'));
                });

                canvas = document.createElement("canvas");
                canvas.className = "screenShotTempCanvas";
                //convert SVG into a XML string
                xml = (new XMLSerializer()).serializeToString(this);

                // Removing the name space as IE throws an error
                xml = xml.replace(/xmlns=\"http:\/\/www\.w3\.org\/2000\/svg\"/, '');

                //draw the SVG onto a canvas
                canvg(canvas, xml);
                $(canvas).insertAfter(this);
                //hide the SVG element
                ////this.className = "tempHide";
                $(this).attr('class', 'tempHide');
                $(this).hide();
            });


            html2canvas($("#container"), {
                onrendered: function (canvas) {
                    var a = document.createElement("a");
                    a.download = "Dashboard.png";
                    a.href = canvas.toDataURL("image/png");
                    a.click();
                    var imgData = canvas.toDataURL('image/png');

                    var doc = new jsPDF('p', 'mm','a4');
                    var width = doc.internal.pageSize.width;
                    var height = doc.internal.pageSize.height;

                    doc.addImage(imgData, 'PNG',  0, 0, width, height);
                    doc.save('Dashboard.pdf');
                }
            });

            $("#container").find('.screenShotTempCanvas').remove();
            $("#container").find('.tempHide').show().removeClass('tempHide');

帮帮我吧.提前致谢

推荐答案

您的 svg 元素由外部样式表 nv.d3.min.css 设置样式.

Your svg elements are being styled by the external stylesheet nv.d3.min.css .

canvg 似乎无法访问外部样式表，因此您需要将其直接附加到您的 svg 节点中.

canvg seems unable to access external style sheets, so you need to append it directly in your svg node.

为此，如果您的样式表与脚本托管在同一域中，您可以执行以下操作:

To do so, if your style sheet is hosted on the same domain as your scripts, you can do something like :

var sheets = document.styleSheets;
var styleStr = '';
Array.prototype.forEach.call(sheets, function(sheet){
    try{ // we need a try-catch block for external stylesheets that could be there...
        styleStr += Array.prototype.reduce.call(sheet.cssRules, function(a, b){
            return a + b.cssText; // just concatenate all our cssRules' text
            }, "");
        }
    catch(e){console.log(e);}
});
// create our svg nodes that will hold all these rules
var defs = document.createElementNS('http://www.w3.org/2000/svg', 'defs');
var style = document.createElementNS('http://www.w3.org/2000/svg', 'style');
style.innerHTML = styleStr;
defs.appendChild(style);
// now append it in your svg node
thesvg[0].insertBefore(defs, thesvg[0].firstElementChild);

所以现在你可以调用 XMLSerializer，canvg 会很高兴.

So now you can call the XMLSerializer, and canvg will be happy.

分叉的 plunkr，我在那里复制了 nv.d3.min.css 的内容到同源 style.css.

Forked plunkr, where I copied the nv.d3.min.css's content to a same-origin style.css.

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