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| <!DOCTYPE html> | |
| <html> | |
| <head> | |
| <meta http-equiv="Content-type" content="text/html; charset=utf-8"> | |
| <title>Testing Pie Chart</title> | |
| <script type="text/javascript" src="http://mbostock.github.com/d3/d3.js?2.1.3"></script> | |
| <script type="text/javascript" src="http://mbostock.github.com/d3/d3.geom.js?2.1.3"></script> | |
| <script type="text/javascript" src="http://mbostock.github.com/d3/d3.layout.js?2.1.3"></script> | |
| <style type="text/css"> | |
| .slice text { | |
| font-size: 16pt; | |
| font-family: Arial; | |
| } | |
| </style> | |
| </head> | |
| <body> | |
| <script type="text/javascript"> | |
| var w = 300, //width | |
| h = 300, //height | |
| r = 100, //radius | |
| color = d3.scale.category20c(); //builtin range of colors | |
| data = [{"label":"one", "value":20}, | |
| {"label":"two", "value":50}, | |
| {"label":"three", "value":30}]; | |
| var vis = d3.select("body") | |
| .append("svg:svg") //create the SVG element inside the <body> | |
| .data([data]) //associate our data with the document | |
| .attr("width", w) //set the width and height of our visualization (these will be attributes of the <svg> tag | |
| .attr("height", h) | |
| .append("svg:g") //make a group to hold our pie chart | |
| .attr("transform", "translate(" + r + "," + r + ")") //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(r); | |
| var pie = d3.layout.pie() //this will create arc data for us given a list of values | |
| .value(function(d) { return d.value; }); //we must tell it out to access the value of each element in our data array | |
| var arcs = vis.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) | |
| 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 | |
| arcs.append("svg:text") //add a label to each slice | |
| .attr("transform", function(d) { //set the label's origin to the center of the arc | |
| //we have to make sure to set these before calling arc.centroid | |
| d.innerRadius = 0; | |
| d.outerRadius = r; | |
| return "translate(" + arc.centroid(d) + ")"; //this gives us a pair of coordinates like [50, 50] | |
| }) | |
| .attr("text-anchor", "middle") //center the text on it's origin | |
| .text(function(d, i) { return data[i].label; }); //get the label from our original data array | |
| </script> | |
| </body> | |
| </html> |
Thanks makc !
How can you dynamically update the chart in this example? Updating charts is pretty straightforward if it's a basic dataset like [100,200,300], but in this case, since the dataset is more complex, I'm not sure how to update it.
@Jakobud you're gonna want to use a 'key' function: http://bost.ocks.org/mike/constancy/
Hello, is there a way to put the label on multiple lines if it's quite long?
what's that vis stands for?
excellent, thanks!
@kaanozcan vis stands for visual which is short for visualization
Great stuff, thanks OP!
@frostyfrog funny to see you here.
I modified this code a bit, and I'm getting an odd bug that maybe someone can help me out with?
I basically created a new "data" array that has 12 values (instead of the 3 that are in this example), and now the values are being switched around on the pie chart...0 becomes 6, 1 becomes 0, and 6 becomes 1.
Anybody got any ideas on why this would happen?
PS...when I make the array 10 or fewer elements, this value switching doesn't happen at all...
Should there be a semi-colon after .attr("transform", "translate(" + r + "," + r + ")")?
how can i add more slices?
and here is a fork to display the value in the slice: https://gist.github.com/MohamedAlaa/246b7d45e20be8680394
Is there a way to customize the text that shows up in the label? color, font-size, etc?
I was able to answer my own question. Some styles, like font-size you can adjust in the CSS. You can also add the border between the slices with CSS by using stroke (in Less for simplicity):
.slice {
path {
stroke:#fff;
stroke-width:0.5;
}
text {
font-size:0.9em;
}
}
But for the text color, you need to add another attribute called "fill" to the arcs as such:
.attr("fill", "white")
"simple" example? I think not
@stevematdavies The resulting pie chart is quite simple.
How can I get the data from a Backbone model?
Question: why do you have to put [data] in the extra level of array when creating the outer svg element? The code doesn't work if you just pass data to the data() function:
.data(data) // fails
but
.data([data]) // works
I really don't understand this.
How do i assign the code to a function so i can just call it on a different data set later
@bethrobson The current selection only contains 1 element, the svg tag. You want to attach the whole of data so it will be passed on to the child tags of svg. You do this by creating an array with 1 element and bind that to the selection. If you do .data(data) you only bind the first data-point to the svg.
An alternative is not to bind anything to the svg
var vis = d3.select("body")
.append("svg:svg")
.attr("width", w)
.attr("height", h)
.append("svg:g")
.attr("transform", "translate(" + r + "," + r + ")");
and add the data to the call to pie
var arcs = vis.selectAll("g.slice")
.data(pie(data))
.enter()
.append("svg:g")
.attr("class", "slice");
tried running it on jsfiddle - dropping the link here for readers convenience :)