我们有一个使用 highchart js 库并将图表呈现为 SVG 的 angular js 应用程序。我们制作了几个显示数据组合的小部件，假设在一些小部件中我们只有 SVG 图表，在一些小部件中我们只有用 Angular Directive(指令)呈现的表格数据，而在一些小部件中我们有两者的组合，即一些图表 + 一些 HTML(它可以是简单的项目符号列表，也可以是用 Angular 呈现的表格数据)。现在我们想要提供功能，以便每个小部件都可以导出为图像。
我们遇到了这个例子 jsfiddle.net/8ypxW/3/，它使用 html2canvas 库并且可以很好地处理纯 HTML 数据，但是 SVG 图表不会用这个导出。
我们想通过 C# 从服务器端生成图像，但是每个小部件都是用 js 库(highchart 和 angular)生成的，所以在这种情况下我们在服务器端没有任何直接支持。
上述情况的解决方案是什么？或者有什么其他方法可以实现类似的效果。
最佳答案
我认为 dom-to-image.js 比 html 到 canvas 更准确一些，这里有一些技巧:
dom-to-image 让你从 html svg 数据 url 格式生成，是的，我知道你为什么要那样做，它更准确，用那个 svg 图像绘制在 Canvas 内(你的情况需要什么，或者更复杂的东西，如果你需要像我的例子一样在图像中打印整个页面)。从该 Canvas 中，您可以拉取图像、调整大小并下载。
版权: http://jsfiddle.net/gregfedorov/Qh9X5/9/ 和 http://jsfiddle.net/christopheviau/v6VMf/
///dom to svg module
document.getElementById('downloadbody').onclick= function(){
var wrapper = document.getElementsByTagName("BODY")[0];
//dom to image
domtoimage.toSvg(wrapper).then(function (svgDataUrl) {
//download function
downloadPNGFromAnyImageSrc(svgDataUrl);
});
}
document.getElementById('downloadcircle').onclick= function(){
var wrapper = document.getElementById('circle');
//dom to image
domtoimage.toSvg(wrapper).then(function (svgDataUrl) {
//download function
downloadPNGFromAnyImageSrc(svgDataUrl);
});
}
document.getElementById('downloadtable').onclick= function(){
var wrapper = document.getElementById('table');
//dom to image
domtoimage.toSvg(wrapper).then(function (svgDataUrl) {
//download function
downloadPNGFromAnyImageSrc(svgDataUrl);
});
}
function downloadPNGFromAnyImageSrc(src)
{
//recreate the image with src recieved
var img = new Image;
//when image loaded (to know width and height)
img.onload = function(){
//drow image inside a canvas
var canvas = convertImageToCanvas(img);
//get image/png from convas
var pngImage = convertCanvasToImage(canvas);
//download
var anchor = document.createElement('a');
anchor.setAttribute('href', pngImage.src);
anchor.setAttribute('download', 'image.png');
anchor.click();
};
img.src = src;
// Converts image to canvas; returns new canvas element
function convertImageToCanvas(image) {
var canvas = document.createElement("canvas");
canvas.width = image.width;
canvas.height = image.height;
canvas.getContext("2d").drawImage(image, 0, 0);
return canvas;
}
// Converts canvas to an image
function convertCanvasToImage(canvas) {
var image = new Image();
image.src = canvas.toDataURL("image/png");
return image;
}
}
////// svg's generations
////CIrcle Modeule///////
var dataset = {
apples: [53245, 28479, 19697, 24037, 40245],
};
var width = 460,
height = 300,
radius = Math.min(width, height) / 2;
var color = d3.scale.category20();
var pie = d3.layout.pie()
.sort(null);
var arc = d3.svg.arc()
.innerRadius(radius - 100)
.outerRadius(radius - 50);
var svg = d3.select("#circle").append("svg")
.attr("width", width)
.attr("height", height)
.append("g")
.attr("transform", "translate(" + width / 2 + "," + height / 2 + ")");
var path = svg.selectAll("path")
.data(pie(dataset.apples))
.enter().append("path")
.attr("fill", function(d, i) { return color(i); })
.attr("d", arc);
// Table module ////////////////////////////////////
var Table = function module() {
var opts = {
width: 200,
height: 200,
margins: {top: 20, right: 20, bottom: 20, left: 20}
};
function exports(selection) {
selection.each(function (dataset) {
//________________________________________________
// Data
//________________________________________________
var columnLabel = dataset.columnLabel;
var rowLabel = dataset.rowLabel;
var value = dataset.value;
//________________________________________________
// DOM preparation
//________________________________________________
// Size
var chartW = Math.max(opts.width - opts.margins.left - opts.margins.right, 0.1);
var chartH = Math.max(opts.height - opts.margins.top - opts.margins.bottom, 0.1);
// SVG
var parentDiv = d3.select(this).html('');
var svg = parentDiv.append('svg').attr('width', opts.width).attr('height', opts.height);
var visSvg = svg.append('g').attr('class', 'vis-group').attr('transform', 'translate(' + opts.margins.left + ',' + opts.margins.top + ')');
var tableBodySvg = visSvg.append('g').attr('class', 'chart-group');
var tableHeaderSvg = visSvg.append('g').attr('class', 'chart-group');
var rowHeaderSvg = tableHeaderSvg.append('g').attr('class', 'row-header');
var colHeaderSvg = tableHeaderSvg.append('g').attr('class', 'col-header');
//________________________________________________
// Table
//________________________________________________
var rowHeaderLevelNum = 1;
var colHeaderLevelNum = 1;
var cellH = chartH / (value.length + rowHeaderLevelNum);
var cellW = chartW / (value[0].length + colHeaderLevelNum);
// Row header
var rowHeaderCell = rowHeaderSvg.selectAll('rect.row-header-cell')
.data(rowLabel);
rowHeaderCell.enter().append('rect')
.attr({
class:'row-header-cell',
width:cellW, height:cellH,
x: 0,
y: function(d, i){return i * cellH + (cellH * colHeaderLevelNum)}
})
.style({fill:'#eee', stroke:'silver'});
// Row header text
rowHeaderCell.enter().append('text')
.attr({
class:'row-header-content',
x: 0,
y: function(d, i){return i * cellH + (cellH * colHeaderLevelNum)},
dx: cellW/2,
dy: cellH/2
})
.style({fill:'black', 'text-anchor':'middle'})
.text(function(d, i){return d;});
// Col header
var colHeaderCell = colHeaderSvg.selectAll('rect.col-header-cell')
.data(columnLabel);
colHeaderCell.enter().append('rect')
.attr({
class:'col-header-cell',
width:cellW, height:cellH,
x: function(d, i){return i * cellW + (cellW * rowHeaderLevelNum)},
y: 0
})
.style({fill:'#eee', stroke:'silver'});
// Col header text
colHeaderCell.enter().append('text')
.attr({
class:'col-header-content',
x: function(d, i){return i * cellW + (cellW * rowHeaderLevelNum)},
y: 0,
dx: cellW/2,
dy: cellH/2
})
.style({fill:'black', 'text-anchor':'middle'})
.text(function(d, i){return d;});
// Body
var row = tableBodySvg.selectAll('g.row')
.data(value);
row.enter().append('g')
.attr('class', 'cell row')
.each(function(pD, pI){
// Cells
var cell = d3.select(this)
.selectAll('rect.cell')
.data(pD);
cell.enter().append('rect')
.attr({
class:'cell', width:cellW, height:cellH,
x: function(d, i){return i * cellW + (cellW * rowHeaderLevelNum)},
y: function(d, i){return pI * cellH + cellH}
})
.style({fill:'white', stroke:'silver'});
// Text
cell.enter().append('text')
.attr({
class:'cell-content', width:cellW, height:cellH,
x: function(d, i){return i * cellW + (cellW * rowHeaderLevelNum)},
y: function(d, i){return pI * cellH + cellH},
dx: cellW/2,
dy: cellH/2
})
.style({fill:'black', 'text-anchor':'middle'})
.text(function(d, i){return d;});
});
});
}
exports.opts = opts;
createAccessors(exports, opts);
return exports;
};
// Helper function ////////////////////////////////////
var createAccessors = function(visExport) {
for (var n in visExport.opts) {
if (!visExport.opts.hasOwnProperty(n)) continue;
visExport[n] = (function(n) {
return function(v) {
return arguments.length ? (visExport.opts[n] = v, this) : visExport.opts[n];
}
})(n);
}
};
// Usage ////////////////////////////////////
var dataset = {
rowLabel: ['A', 'B', 'C', 'D', 'E'],
columnLabel: ['P', 'Q', 'R', 'S'],
value: [[1, 2, 3, 4], [5, 6, 7, 8], [9, 10, 11, 12], [13, 14, 15, 16], [17, 18, 19, 20]]
};
var width = 400;
var height = 300;
var table = Table().width(width).height(height);
d3.select('#table')
.datum(dataset)
.call(table);body {
font-family: "Helvetica Neue", Helvetica, Arial, sans-serif;
margin: auto;
position: relative;
width: 960px;
background-color:blue;
}
text {
font: 10px sans-serif;
}
form {
position: absolute;
right: 10px;
top: 10px;
}<script src="https://mbostock.github.io/d3/d3.js"></script>
<script src="https://rawgit.com/tsayen/dom-to-image/master/src/dom-to-image.js"></script>
<div>
Using dom-to-image.js transform anny given html to a image (svg - no quality loss)<br>
1. tansform html into svg<br>
2. drow svg inside hidden canvas<br>
3. export canvas jpg or png<br>
4. I you like donwload the thing<br>
</div>
<button id='downloadbody'>Download body</button>
<button id='downloadcircle'>Download Circle</button>
<button id='downloadtable'>Download Table</button>
<div id="circle">
</div>
<div id="table">
</div>关于JavaScript - 使用 SVG 图表 + HTML 和图像导出 Div，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/40602732/