svg 要素を canvas でレンダリングするサンプル。
マウスオーバーで出現するアイコンをクリックすると svg 要素を canvas でレンダリングし、png としてダウンロードする。
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March 20, 2016 07:15
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| <!DOCTYPE html> | |
| <meta charset="utf-8"> | |
| <script src="//d3js.org/d3.v3.min.js"></script> | |
| <script src="renderer.js"></script> | |
| <body> | |
| <script> | |
| var width = 960; | |
| var height = 500; | |
| var rt3 = 1.7320508075688772935274463415059; | |
| var svg = d3.select('body') | |
| .append('svg') | |
| .attr('width', width) | |
| .attr('height', height); | |
| var layer = svg.append('g').attr('transform', 'translate('+width/2+',0)'); | |
| var points = [{x:-height/rt3, y:height, seed:true},{x:height/rt3, y:height, seed:false}]; | |
| var step = function(a) | |
| { | |
| var ret = []; | |
| d3.range(a.length).forEach(function(i) | |
| { | |
| var seed = a[i].seed; | |
| a[i].seed = false; | |
| ret.push(a[i]); | |
| if (seed) | |
| { | |
| var dx = (a[i+1].x - a[i].x)/2; | |
| var dy = (a[i+1].y - a[i].y)/2; | |
| ret.push({x: a[i].x+dx, y: a[i].y+dy, seed:true}); | |
| ret.push({x: a[i].x+dx/2+rt3*dy/2, y: a[i].y+dy/2-rt3*dx/2, seed:true}); | |
| ret.push({x: a[i].x+3*dx/2+rt3*dy/2, y: a[i].y+3*dy/2-rt3*dx/2, seed:true}); | |
| ret.push({x: a[i].x+dx, y: a[i].y+dy, seed:false}); | |
| } | |
| }); | |
| return ret; | |
| } | |
| var gasket = function(a) { return 'M0,0 ' + a.map(function(d){return 'L'+d.x+','+d.y;}).join(' ') + ' z'; } | |
| var triangle = layer.append('path').attr('fill', '#CCC').attr('d', gasket(points)); | |
| var tick = function(depth) | |
| { | |
| if (depth > 5) | |
| { | |
| return; | |
| } | |
| points = step(points); | |
| var dummy = []; | |
| var p = null; | |
| points.forEach(function(d) | |
| { | |
| if (d.seed) | |
| { | |
| if (p==null) | |
| { | |
| p = d; | |
| } | |
| dummy.push(p); | |
| } | |
| else | |
| { | |
| dummy.push(d); | |
| p = null; | |
| } | |
| }); | |
| triangle.attr('d', gasket(dummy)) | |
| .transition().duration(10000) | |
| .attr('d', gasket(points)) | |
| .each('end', function(){tick(depth+1)}); | |
| } | |
| tick(0); | |
| var r = renderer() | |
| .source(svg.node()) | |
| .target(d3.select('body').node()) | |
| .cb(function(err,canvas) | |
| { | |
| if (err != null) | |
| { | |
| console.log(err); | |
| return; | |
| } | |
| var tag = d3.select('body').append('a') | |
| .attr('type','application/octet-stream') | |
| .attr('href', canvas.toDataURL('image/png')) | |
| .attr('download','image.png'); | |
| tag.node().click(); | |
| tag.remove(); | |
| canvas.remove(); | |
| }); | |
| var icon = svg.append('image') | |
| .attr('width', 256) | |
| .attr('height', 256) | |
| .attr('x',width/2-128) | |
| .attr('y', height/2-128) | |
| .attr('opacity', 0.8) | |
| .attr('xlink:href','downloadbtn.png') | |
| .on('click', r); | |
| icon.transition().duration(2000).attr('opacity', 0.0); | |
| svg.on('mouseover', function() | |
| { | |
| icon.transition().attr('opacity', 0.8); | |
| }) | |
| .on('mouseout', function() | |
| { | |
| icon.transition().attr('opacity', 0.0); | |
| }) | |
| </script> |
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| !(function() | |
| { | |
| var constant = function(d) | |
| { | |
| return function() | |
| { | |
| return d; | |
| } | |
| } | |
| var renderer = function() | |
| { | |
| var _source = function(d){return this;} | |
| var _target = function(d){return this.parentNode;} | |
| var _cb = function(e,d){} | |
| function _renderer() | |
| { | |
| var source = _source.apply(this, arguments); | |
| var target = _target.apply(this, arguments); | |
| var cb = _cb; | |
| var canvas = document.createElement('canvas'); | |
| try | |
| { | |
| var ns = source.getAttribute('xmlns'); | |
| source.setAttribute('xmlns', 'http://www.w3.org/2000/svg'); | |
| target.appendChild(canvas); | |
| canvas.setAttribute('width', source.clientWidth); | |
| canvas.setAttribute('height', source.clientHeight); | |
| var ctx = canvas.getContext('2d'); | |
| var data = new Blob([source.outerHTML], | |
| {type: 'image/svg+xml; charset=utf-8'}); | |
| var img = new Image(); | |
| var blobReader = new FileReader(); | |
| blobReader.onload = function() | |
| { | |
| img.onload = function() | |
| { | |
| ctx.drawImage(img, 0, 0); | |
| if (ns == null) | |
| { | |
| source.removeAttribute('xmlns'); | |
| } | |
| else | |
| { | |
| source.setAttribute('xmlns', ns) | |
| } | |
| cb(null, canvas); | |
| } | |
| img.src = this.result; | |
| } | |
| blobReader.readAsDataURL(data); | |
| } | |
| catch (e) | |
| { | |
| canvas.remove(); | |
| cb(e, null); | |
| } | |
| } | |
| _renderer.source = function(_) | |
| { | |
| return arguments.length ? (_source = typeof _ === 'function' ? _ : constant(_), _renderer): _source; | |
| } | |
| _renderer.target = function(_) | |
| { | |
| return arguments.length ? (_target = typeof _ === 'function' ? _ : constant(_), _renderer): _target; | |
| } | |
| _renderer.cb = function(_) | |
| { | |
| return arguments.length ? (_cb = typeof _ === 'function' ? _ : constant(_), _renderer): _cb; | |
| } | |
| return _renderer; | |
| } | |
| if (typeof define === "function" && define.amd) define(renderer); | |
| else if (typeof module === "object" && module.exports) module.exports = renderer; | |
| this.renderer = renderer; | |
| }()); |
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