I have a matrix of circles that I created like this:
var maxColumn = 6;
graphGroup.selectAll('circle')
.data(data)
.enter()
.append('circle')
.attr('id', function(d,i) {return 'c'+String(i)})
.attr('cx', function(d, i) {
return (i % maxColumn) * 200
})
.attr('cy', function(d, i) {
return ~~((i / maxColumn) % maxColumn) * 180
})
.attr('r', function(d) {return rScale(d.Trust)})
.style('fill', '#003366');
Then I wanted to try and append curved text within each circle with the date corresponding to that circle. I thought all I had to do was reference a curved svg element for the text to curve using .attr("xlink:href",function(d,i){return "#c"+i;})
but actually nothing was appended at all. Here is the text portion:
graphGroup.selectAll('text')
.data(data)
.enter()
.append("text")
.style("font-size",20)
.append("textPath")
.attr("textLength",function(d,i){return 100 ;})
.attr("xlink:href",function(d,i){return "#c"+i;})
.attr("startOffset",function(d,i){return 3/20;})
.attr("dy","-1em")
.text(function(d){return d.date;})
Is there an easier way to add curved text to each of my circles, or what is a sensible way to proceed?
As the name implies, a <textPath>
must be used with a <path>
element. You cannot use it with a <circle>
. If you look at the SVG specifications :
In addition to text drawn in a straight line, SVG also includes the ability to place text along the shape of a 'path' element. To specify that a block of text is to be rendered along the shape of a 'path', include the given text within a 'textPath' element which includes an 'xlink:href' attribute with an IRI reference to a 'path' element.
Note: that's for SVG 1, for SVG 2 see the comment below .
Therefore, you have to create paths. You can convert your circles to paths dealing with the d
attribute. For instance, supposing your cx = 100
, cy = 100
and r = 30
, this would be the d
attribute:
d = "M70,100 a 30,30 0 1,0 60,0 a 30,30 0 1,0 -60,0";
There are several online resources explaining how do you calculate the d
attribute based on cx
, cy
and r
, like this one .
Here is a demo:
const svg = d3.select("svg"); const circle = svg.append("path") .style("fill", "none") .style("stroke", "black") .attr("d", "M70,100 a 30,30 0 1,0 60,0 a 30,30 0 1,0 -60,0");
<script src="https://cdnjs.cloudflare.com/ajax/libs/d3/5.7.0/d3.min.js"></script> <svg></svg>
Now you can append the <textPath>
:
const svg = d3.select("svg"); const circle = svg.append("path") .style("fill", "none") .style("stroke", "black") .attr("d", "M70,100 a 30,30 0 1,0 60,0 a 30,30 0 1,0 -60,0") .attr("id", "myPath"); const textpath = svg.append("text") .append("textPath") .attr("xlink:href", "#myPath") .text("Foo Bar Baz")
<script src="https://cdnjs.cloudflare.com/ajax/libs/d3/5.7.0/d3.min.js"></script> <svg></svg>
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