为什么不复制SVG节点/树，然后按标签定义的样式进行处理（您需要原始树，因为如果元素是长树的一部分，则复制可能没有样式）。这确保您只复制CSS文件中设置的相关样式。在将包发送到blob之前，可以轻松地设置导出类型。
var ContainerElements = ["svg","g"];
var RelevantStyles = {"rect":["fill","stroke","stroke-width"],"path":["fill","stroke","stroke-width"],"circle":["fill","stroke","stroke-width"],"line":["stroke","stroke-width"],"text":["fill","font-size","text-anchor"],"polygon":["stroke","fill"]};
function read_Element(ParentNode, OrigData){
var Children = ParentNode.childNodes;
var OrigChildDat = OrigData.childNodes;
for (var cd = 0; cd < Children.length; cd++){
var Child = Children[cd];
var TagName = Child.tagName;
if (ContainerElements.indexOf(TagName) != -1){
read_Element(Child, OrigChildDat[cd])
} else if (TagName in RelevantStyles){
var StyleDef = window.getComputedStyle(OrigChildDat[cd]);
var StyleString = "";
for (var st = 0; st < RelevantStyles[TagName].length; st++){
StyleString += RelevantStyles[TagName][st] + ":" + StyleDef.getPropertyValue(RelevantStyles[TagName][st]) + "; ";
}
Child.setAttribute("style",StyleString);
}
}
}
function export_StyledSVG(SVGElem){
var oDOM = SVGElem.cloneNode(true)
read_Element(oDOM, SVGElem)
var data = new XMLSerializer().serializeToString(oDOM);
var svg = new Blob([data], { type: "image/svg+xml;charset=utf-8" });
var url = URL.createObjectURL(svg);
var link = document.createElement("a");
link.setAttribute("target","_blank");
var Text = document.createTextNode("Export");
link.appendChild(Text);
link.href=url;
document.body.appendChild(link);
}
在保存SVG元素之前，您需要明确将计算出的CSS样式设置为每个SVG元素的SVG DOM样式属性。
以下是一个示例：
<html>
<body>
<!-- in this example the inline svg has black backgroud-->
<svg id="svg" xmlns="http://www.w3.org/2000/svg" version="1.1" height="190">
<polygon id="polygon" points="100,10 40,180 190,60 10,60 160,180" style="stroke:purple;stroke-width:5;">
</svg>
<style>
/* the external svg style makes svg shape background red */
polygon
{
fill:red;
}
</style>
<svg id="emptysvg" xmlns="http://www.w3.org/2000/svg" version="1.1" height="2"/>
<br/>
image original:
<canvas id="canvasOriginal" height="190" width="190" ></canvas>
<br/>
image computed:
<canvas id="canvasComputed" height="190" width="190" ></canvas>
<script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/1.9.0/jquery.min.js"></script>
<script type="text/javascript" src="http://canvg.googlecode.com/svn/trunk/rgbcolor.js"></script>
<script type="text/javascript" src="http://canvg.googlecode.com/svn/trunk/StackBlur.js"></script>
<script type="text/javascript" src="http://canvg.googlecode.com/svn/trunk/canvg.js"></script>
<script src="http://www.nihilogic.dk/labs/canvas2image/canvas2image.js"></script>
<script type="text/javascript">
var svg = $('#svg')[0];
var canvasOriginal = $('#canvasOriginal')[0];
var ctxOriginal = canvasOriginal.getContext('2d');
var canvasComputed=$('#canvasComputed')[0];
var ctxConverted=canvasComputed.getContext("2d");
// this saves the inline svg to canvas without external css
canvg('canvasOriginal', new XMLSerializer().serializeToString(svg));
// we need to calculate the difference between the empty svg and ours
var emptySvgDeclarationComputed = getComputedStyle($('#emptysvg')[0]);
function explicitlySetStyle (element) {
var cSSStyleDeclarationComputed = getComputedStyle(element);
var i, len, key, value;
var computedStyleStr = "";
for (i=0, len=cSSStyleDeclarationComputed.length; i<len; i++) {
key=cSSStyleDeclarationComputed[i];
value=cSSStyleDeclarationComputed.getPropertyValue(key);
if (value!==emptySvgDeclarationComputed.getPropertyValue(key)) {
computedStyleStr+=key+":"+value+";";
}
}
element.setAttribute('style', computedStyleStr);
}
function traverse(obj){
var tree = [];
tree.push(obj);
if (obj.hasChildNodes()) {
var child = obj.firstChild;
while (child) {
if (child.nodeType === 1 && child.nodeName != 'SCRIPT'){
tree.push(child);
}
child = child.nextSibling;
}
}
return tree;
}
// hardcode computed css styles inside svg
var allElements = traverse(svg);
var i = allElements.length;
while (i--){
explicitlySetStyle(allElements[i]);
}
// this saves the inline svg to canvas with computed styles
canvg('canvasComputed', new XMLSerializer().serializeToString(svg));
$("canvas").click(function (event) {
Canvas2Image.saveAsPNG(event.target);
});
</script>
</body>
</html>
explicitlySetStyle 的元素 $('#svg').find("*");。 - CraigRead the .css file, which contains all the css rule. If required, you can use a different css file and put it on the server, which you can only use for this purpose.
function readTextFile(file) {
var rawFile = new XMLHttpRequest();
var allText = '';
rawFile.open("GET", file, false);
rawFile.onreadystatechange = function () {
if(rawFile.readyState === 4) {
if(rawFile.status === 200 || rawFile.status == 0) {
allText = rawFile.responseText;
}
}
};
rawFile.send(null);
return allText;
}
var svg_style = readTextFile(base_url + '/css/svg_sm_dashboard.css');
Now apply the style on all the svg elements
var all_style = svg_style.replace(/\r?\n|\r/g,'').split('}');
all_style.forEach(function(el) {
if (el.trim() != '') {
var full_rule_string = el.split('{');
var selector = full_rule_string[0].trim();
var all_rule = full_rule_string[1].split(';');
all_rule.forEach(function (elem) {
if (elem.trim() != '') {
var attr_value = elem.split(':');
//d3.selectAll(selector).style(attr_value[0].trim() + '', attr_value[1].trim() + '');
var prop = attr_value[0].trim();
var value = attr_value[1].trim();
d3.selectAll(selector).each(function(d, i){
if(!this.getAttribute(prop) && !this.style[prop]){
d3.select(this).style(prop + '', value + '');
}
});
}
});
}
});
Use canvg to convert it
$('body').after('<canvas id="sm_canvas" style="display=none;"></canvas>');
var canvas = document.getElementById('sm_canvas');
canvg(canvas, $("<div>").append($('svg').clone()).html());
Get Image from the canvas
var imgData = canvas.toDataURL('image/jpeg');