Created
October 3, 2012 02:48
Make an element follow a path
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| <!DOCTYPE html> | |
| <html> | |
| <head> | |
| <meta http-equiv="Content-Type" content="text/html;charset=utf-8"/> | |
| <style type="text/css"> | |
| #line{ | |
| width: 100%; | |
| margin: 20px 0; | |
| height: 300px; | |
| background: #eee; | |
| } | |
| path { | |
| stroke: steelblue; | |
| stroke-width: 1; | |
| fill: none; | |
| } | |
| button { | |
| margin: 20px 0 0 20px; | |
| } | |
| </style> | |
| </head> | |
| <body> | |
| <button id="randomize">Create random line</button> | |
| <div id="line"></div> | |
| <script type="text/javascript" src="http://mbostock.github.com/d3/d3.js?2.5.0"></script> | |
| <script type="text/javascript"> | |
| var svg = d3.select("#line").append("svg:svg").attr("width", "100%").attr("height", "100%"); | |
| var data = d3.range(50).map(function(){return Math.random()*10}) | |
| var x = d3.scale.linear().domain([0, 10]).range([0, 700]); | |
| var y = d3.scale.linear().domain([0, 10]).range([10, 290]); | |
| var line = d3.svg.line() | |
| .interpolate("cardinal") | |
| .x(function(d,i) {return x(i);}) | |
| .y(function(d) {return y(d);}) | |
| var path = svg.append("svg:path").attr("d", line(data)); | |
| var circle = | |
| svg.append("circle") | |
| .attr("cx", 100) | |
| .attr("cy", 350) | |
| .attr("r", 3) | |
| .attr("fill", "red"); | |
| var pathEl = path.node(); | |
| var pathLength = pathEl.getTotalLength(); | |
| var BBox = pathEl.getBBox(); | |
| var scale = pathLength/BBox.width; | |
| var offsetLeft = document.getElementById("line").offsetLeft; | |
| var randomizeButton = d3.select("button"); | |
| svg.on("mousemove", function() { | |
| var x = d3.event.pageX - offsetLeft; | |
| var beginning = x, end = pathLength, target; | |
| while (true) { | |
| target = Math.floor((beginning + end) / 2); | |
| pos = pathEl.getPointAtLength(target); | |
| if ((target === end || target === beginning) && pos.x !== x) { | |
| break; | |
| } | |
| if (pos.x > x) end = target; | |
| else if (pos.x < x) beginning = target; | |
| else break; //position found | |
| } | |
| circle | |
| .attr("opacity", 1) | |
| .attr("cx", x) | |
| .attr("cy", pos.y); | |
| }); | |
| randomizeButton.on("click", function(){ | |
| data = d3.range(50).map(function(){return Math.random()*10}); | |
| circle.attr("opacity", 0) | |
| path | |
| .transition() | |
| .duration(300) | |
| .attr("d", line(data)); | |
| }); | |
| </script> | |
| </body> | |
| </html> |
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