如何保存/导出使用CSS从浏览器到图像文件样式的内联SVG

Question

如何保存/导出使用CSS从浏览器到图像文件样式的内联SVG

joh*_*wie 21 javascript browser svg export image

我有一个Web应用程序,它根据用户交互动态在客户端生成内联SVG图形.图形部分由元素属性定义,部分由CSS类和id定义.

我希望能够为客户端提供一个选项,将内联SVG的副本保存为位图或.svg图像文件.从外部CSS样式文件应用所有样式非常重要.我如何提供此功能以保存为.svg或位图(.gif),最好是在浏览器中使用javascript,或者在服务器上使用node.js？

Answer 1

小智 16

为什么不复制SVG节点/树然后采用样式,作为每个标记的defiend(您将需要原始树,因为如果元素是较长树的一部分,副本可能没有样式).这可确保您只复制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);
}

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Answer 2

Ily*_*mov 8

在保存之前,您需要将计算出的css样式显式设置为每个SVG元素的SVG dom样式属性.这是一个例子:

<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>

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那个遍历函数似乎只有一层深,这对我没用.使用jQuery,以下行可以通过`explicitSetStyle`` $('#svg')获取所有准备运行的元素.find("*");` (2认同)

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