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May 12, 2017 14:44
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update dots on canvas
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| license: mit |
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
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| <!DOCTYPE html> | |
| <head> | |
| <meta charset="utf-8"> | |
| <script src="https://d3js.org/d3.v4.min.js"></script> | |
| <style> | |
| body { margin:0;position:fixed;top:0;right:0;bottom:0;left:0; } | |
| </style> | |
| </head> | |
| <body> | |
| <div id="vis"></div> | |
| <script> | |
| var data = [ | |
| { | |
| label: 'foo', | |
| amount: 8 | |
| }, | |
| { | |
| label: 'bar', | |
| amount: 6 | |
| }, | |
| { | |
| label: 'lol', | |
| amount: 1 | |
| } | |
| ]; | |
| var base = d3.select("#vis"); | |
| var width = 400; | |
| var chart = base.append("canvas") | |
| .attr("width", 400) | |
| .attr("height", 300); | |
| var context = chart.node().getContext("2d"); | |
| // Create an in memory only element of type 'custom' | |
| var detachedContainer = document.createElement("custom"); | |
| // Create a d3 selection for the detached container | |
| var dataContainer = d3.select(detachedContainer); | |
| // Function to create our custom data containers | |
| function drawCustom(data) { | |
| var scale = d3.scaleBand().rangeRound([0, width]) | |
| .domain(data.map(function(d) { | |
| return d.label; | |
| })); | |
| var dataBinding = dataContainer | |
| .selectAll("custom.circle") | |
| .data(data); | |
| dataBinding | |
| .attr("r", 0) | |
| .transition() | |
| .duration(1000) | |
| .attr("r", function(d) {return d.amount*5}) | |
| .attr("fillStyle", "lightblue"); | |
| dataBinding.enter() | |
| .append("custom") | |
| .classed("circle", true) | |
| .attr("cx", function(d) { | |
| return scale(d.label) + 80; | |
| }) | |
| .attr("cy", 100) | |
| .attr("r", function(d) {return d.amount*5}) | |
| .attr("fillStyle", "lightcoral"); | |
| dataBinding.exit() | |
| .attr("r", function(d) {return d.amount*5}) | |
| .transition() | |
| .duration(1000) | |
| .attr("r", 0) | |
| .attr("fillStyle", "lightgrey"); | |
| } | |
| // Function to render out to canvas our custom | |
| // in memory nodes | |
| function drawCanvas() { | |
| // clear canvas | |
| context.fillStyle = "#fff"; | |
| context.rect(0,0,chart.attr("width"),chart.attr("height")); | |
| context.fill(); | |
| // select our dummy nodes and draw the data to canvas. | |
| var elements = dataContainer.selectAll("custom.circle"); | |
| elements.each(function(d) { | |
| var node = d3.select(this); | |
| context.beginPath(); | |
| context.fillStyle = node.attr("fillStyle"); | |
| context.arc(node.attr("cx"), node.attr("cy"), node.attr("r"),0,2*Math.PI); | |
| context.fill(); | |
| context.closePath(); | |
| }) | |
| } | |
| d3.timer(drawCanvas); | |
| drawCustom(data); | |
| setInterval(function() { | |
| function n() {return Math.random() * (10 - 1) + 1} | |
| newdata = [ | |
| { | |
| label: 'con', | |
| amount: 10 | |
| }, | |
| { | |
| label: 'lab', | |
| amount: n() | |
| }, | |
| { | |
| label: 'lib', | |
| amount: n() | |
| }, | |
| { | |
| label: 'lol', | |
| amount: n() | |
| } | |
| ]; | |
| drawCustom(newdata); | |
| }, 1500); | |
| </script> | |
| </body> |
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