我使用d3创建了一个仪表板（一组3个图表），现在我想将三个图形的集合导出到浏览器中的任何可下载格式。 我引用了以下帖子并尝试下载至少一个图表： SVG to Canvas with d3.js
var formatAsPercentage = d3.format("%"),
formatAsPercentage1Dec = d3.format(".1%"),
formatAsInteger = d3.format(","),
fsec = d3.time.format("%S s"),
fmin = d3.time.format("%M m"),
fhou = d3.time.format("%H h"),
fwee = d3.time.format("%a"),
fdat = d3.time.format("%d d"),
fmon = d3.time.format("%b")
;
// Let's create a mock visualization
function dsPieChart(){
var dataset = [
{category: "apple", measure: 0.30},
{category: "mango", measure: 0.25},
{category: "pineapple", measure: 0.18},
{category: "orange", measure: 0.0},
{category: "peach", measure: 0.18}
]
;
var width = 400,
height = 400,
outerRadius = Math.min(width, height) / 2,
innerRadius = outerRadius * .999,
// for animation
innerRadiusFinal = outerRadius * .5,
innerRadiusFinal3 = outerRadius* .45,
color = d3.scale.category20() //builtin range of colors
;
var svg = d3.select("#pie")
.append("svg:svg") //create the SVG element inside the <body>
.data([dataset]) //associate our data with the document
.attr("width", width) //set the width and height of our visualization (these will be attributes of the <svg> tag
.attr("height", height)
.append("svg:g") //make a group to hold our pie chart
.attr("transform", "translate(" + outerRadius + "," + outerRadius + ")") //move the center of the pie chart from 0, 0 to radius, radius
;
var arc = d3.svg.arc() //this will create <path> elements for us using arc data
.outerRadius(outerRadius).innerRadius(innerRadius);
// for animation
var arcFinal = d3.svg.arc().innerRadius(innerRadiusFinal).outerRadius(outerRadius);
var arcFinal3 = d3.svg.arc().innerRadius(innerRadiusFinal3).outerRadius(outerRadius);
var pie = d3.layout.pie() //this will create arc data for us given a list of values
.value(function(d) { return d.measure; }); //we must tell it out to access the value of each element in our data array
var arcs = svg.selectAll("g.slice") //this selects all <g> elements with class slice (there aren't any yet)
.data(pie) //associate the generated pie data (an array of arcs, each having startAngle, endAngle and value properties)
.enter() //this will create <g> elements for every "extra" data element that should be associated with a selection. The result is creating a <g> for every object in the data array
.append("svg:g") //create a group to hold each slice (we will have a <path> and a <text> element associated with each slice)
.attr("class", "slice") //allow us to style things in the slices (like text)
.on("mouseover", mouseover)
.on("mouseout", mouseout)
.on("click", up)
;
arcs.append("svg:path")
.attr("fill", function(d, i) { return color(i); } ) //set the color for each slice to be chosen from the color function defined above
.attr("d", arc) //this creates the actual SVG path using the associated data (pie) with the arc drawing function
.append("svg:title") //mouseover title showing the figures
.text(function(d) { return d.data.category + ": " + formatAsPercentage(d.data.measure); });
d3.selectAll("g.slice").selectAll("path").transition()
.duration(750)
.delay(10)
.attr("d", arcFinal )
;
// Add a label to the larger arcs, translated to the arc centroid and rotated.
// source: http://bl.ocks.org/1305337#index.html
arcs.filter(function(d) { return d.endAngle - d.startAngle > .2; })
.append("svg:text")
.attr("dy", ".35em")
.attr("text-anchor", "middle")
.attr("transform", function(d) { return "translate(" + arcFinal.centroid(d) + ")rotate(" + angle(d) + ")"; })
//.text(function(d) { return formatAsPercentage(d.value); })
.text(function(d) { return d.data.category; })
;
// Computes the label angle of an arc, converting from radians to degrees.
function angle(d) {
var a = (d.startAngle + d.endAngle) * 90 / Math.PI - 90;
return a > 90 ? a - 180 : a;
}
// Pie chart title
svg.append("svg:text")
.attr("dy", ".35em")
.attr("text-anchor", "middle")
.text("Usage Domainwise")
.attr("class","title")
;
function mouseover() {
d3.select(this).select("path").transition()
.duration(750)
//.attr("stroke","red")
//.attr("stroke-width", 1.5)
.attr("d", arcFinal3)
;
}
function mouseout() {
d3.select(this).select("path").transition()
.duration(750)
//.attr("stroke","blue")
//.attr("stroke-width", 1.5)
.attr("d", arcFinal)
;
}
function up(d, i) {
/* update bar chart when user selects piece of the pie chart */
//updateBarChart(dataset[i].category);
updateBarChart(d.data.category, color(i));
updateBarStatusChart(d.data.category, color(i));
}
// Create an export button
d3.select("body")
.append("button")
.html("Export")
.on("click",svgToCanvas);
var w = 100, // or whatever your svg width is
h = 100;
// Create the export function - this will just export
// the first svg element it finds
function svgToCanvas(){
// Select the first svg element
var svg = d3.select("svg")[0][0],
img = new Image(),
serializer = new XMLSerializer(),
svgStr = serializer.serializeToString(svg);
img.src = 'data:image/svg+xml;base64,'+window.btoa(svgStr);
// You could also use the actual string without base64 encoding it:
//img.src = "data:image/svg+xml;utf8," + svgStr;
var canvas = document.createElement("canvas");
document.body.appendChild(canvas);
canvas.width = w;
canvas.height = h;
canvas.getContext("2d").drawImage(img,0,0,w,h);
// Now save as png or whatever
//var myCanvas = document.getElementsByTagName("canvas")[0];
document.write('<img src="'+canvas[0].toDataURL("image/png")+'"/>');
};
}
dsPieChart();
#pie {
position:absolute;
top:50px;
left:10px;
width:400px;
height: 400px;
}<head>
<script src="https://d3js.org/d3.v3.min.js"></script>
</head>
<body>
<div>
<div id="pie"></div>
</div>
</body>
当我点击导出选项时，它无法识别我的画布元素我尝试了在线提供的各种选项，但没有用。 Soebody请让我知道如何做到这一点 我想要的是当我点击导出时我希望它将我的图形下载为图像
答案 0 :(得分：0)
你错过了image.onLoad函数
var formatAsPercentage = d3.format("%"),
formatAsPercentage1Dec = d3.format(".1%"),
formatAsInteger = d3.format(","),
fsec = d3.time.format("%S s"),
fmin = d3.time.format("%M m"),
fhou = d3.time.format("%H h"),
fwee = d3.time.format("%a"),
fdat = d3.time.format("%d d"),
fmon = d3.time.format("%b")
;
// Let's create a mock visualization
function dsPieChart(){
var dataset = [
{category: "apple", measure: 0.30},
{category: "mango", measure: 0.25},
{category: "pineapple", measure: 0.18},
{category: "orange", measure: 0.0},
{category: "peach", measure: 0.18}
]
;
var width = 400,
height = 400,
outerRadius = Math.min(width, height) / 2,
innerRadius = outerRadius * .999,
// for animation
innerRadiusFinal = outerRadius * .5,
innerRadiusFinal3 = outerRadius* .45,
color = d3.scale.category20() //builtin range of colors
;
var svg = d3.select("#pie")
.append("svg:svg") //create the SVG element inside the <body>
.data([dataset]) //associate our data with the document
.attr("width", width) //set the width and height of our visualization (these will be attributes of the <svg> tag
.attr("height", height)
.append("svg:g") //make a group to hold our pie chart
.attr("transform", "translate(" + outerRadius + "," + outerRadius + ")") //move the center of the pie chart from 0, 0 to radius, radius
;
var arc = d3.svg.arc() //this will create <path> elements for us using arc data
.outerRadius(outerRadius).innerRadius(innerRadius);
// for animation
var arcFinal = d3.svg.arc().innerRadius(innerRadiusFinal).outerRadius(outerRadius);
var arcFinal3 = d3.svg.arc().innerRadius(innerRadiusFinal3).outerRadius(outerRadius);
var pie = d3.layout.pie() //this will create arc data for us given a list of values
.value(function(d) { return d.measure; }); //we must tell it out to access the value of each element in our data array
var arcs = svg.selectAll("g.slice") //this selects all <g> elements with class slice (there aren't any yet)
.data(pie) //associate the generated pie data (an array of arcs, each having startAngle, endAngle and value properties)
.enter() //this will create <g> elements for every "extra" data element that should be associated with a selection. The result is creating a <g> for every object in the data array
.append("svg:g") //create a group to hold each slice (we will have a <path> and a <text> element associated with each slice)
.attr("class", "slice") //allow us to style things in the slices (like text)
.on("mouseover", mouseover)
.on("mouseout", mouseout)
.on("click", up)
;
arcs.append("svg:path")
.attr("fill", function(d, i) { return color(i); } ) //set the color for each slice to be chosen from the color function defined above
.attr("d", arc) //this creates the actual SVG path using the associated data (pie) with the arc drawing function
.append("svg:title") //mouseover title showing the figures
.text(function(d) { return d.data.category + ": " + formatAsPercentage(d.data.measure); });
d3.selectAll("g.slice").selectAll("path").transition()
.duration(750)
.delay(10)
.attr("d", arcFinal )
;
// Add a label to the larger arcs, translated to the arc centroid and rotated.
// source: http://bl.ocks.org/1305337#index.html
arcs.filter(function(d) { return d.endAngle - d.startAngle > .2; })
.append("svg:text")
.attr("dy", ".35em")
.attr("text-anchor", "middle")
.attr("transform", function(d) { return "translate(" + arcFinal.centroid(d) + ")rotate(" + angle(d) + ")"; })
//.text(function(d) { return formatAsPercentage(d.value); })
.text(function(d) { return d.data.category; })
;
// Computes the label angle of an arc, converting from radians to degrees.
function angle(d) {
var a = (d.startAngle + d.endAngle) * 90 / Math.PI - 90;
return a > 90 ? a - 180 : a;
}
// Pie chart title
svg.append("svg:text")
.attr("dy", ".35em")
.attr("text-anchor", "middle")
.text("Usage Domainwise")
.attr("class","title")
;
function mouseover() {
d3.select(this).select("path").transition()
.duration(750)
//.attr("stroke","red")
//.attr("stroke-width", 1.5)
.attr("d", arcFinal3)
;
}
function mouseout() {
d3.select(this).select("path").transition()
.duration(750)
//.attr("stroke","blue")
//.attr("stroke-width", 1.5)
.attr("d", arcFinal)
;
}
function up(d, i) {
/* update bar chart when user selects piece of the pie chart */
//updateBarChart(dataset[i].category);
updateBarChart(d.data.category, color(i));
updateBarStatusChart(d.data.category, color(i));
}
// Create an export button
d3.select("body")
.append("button")
.html("Export")
.on("click",svgToCanvas);
var w = 100, // or whatever your svg width is
h = 100;
// Create the export function - this will just export
// the first svg element it finds
function svgToCanvas(){
// Select the first svg element
debugger;
var svg = d3.select("svg")[0][0],
img = new Image(),
serializer = new XMLSerializer(),
svgStr = serializer.serializeToString(svg);
data = 'data:image/svg+xml;base64,'+window.btoa(svgStr);
var canvas = document.createElement("canvas");
canvas.width = 400;
canvas.height = 400;
context = canvas.getContext("2d");
img.src = data;
img.onload = function() {
context.drawImage(img, 0, 0);
var canvasdata = canvas.toDataURL("image/png");
var pngimg = '<img src="'+canvasdata+'">';
var a = document.createElement("a");
a.download = "sample.png";
a.href = canvasdata;
a.click();
};
};
}
dsPieChart();#pie {
position:absolute;
top:50px;
left:10px;
width:400px;
height: 400px;
}<script src="https://d3js.org/d3.v3.min.js"></script>
<div>
<div id="pie"></div>
</div>