A series of related examples:
- Canvas geometric zooming
- Canvas semantic zooming
- SVG geometric zooming
- SVG semantic zooming
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-
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Canvas Geometric Zooming
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| license: gpl-3.0 |
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| <!DOCTYPE html> | |
| <meta charset="utf-8"> | |
| <canvas width="960" height="500"></canvas> | |
| <script src="https://d3js.org/d3.v4.min.js"></script> | |
| <script> | |
| var canvas = d3.select("canvas").call(d3.zoom().scaleExtent([1, 8]).on("zoom", zoom)), | |
| context = canvas.node().getContext("2d"), | |
| width = canvas.property("width"), | |
| height = canvas.property("height"); | |
| var randomX = d3.randomNormal(width / 2, 80), | |
| randomY = d3.randomNormal(height / 2, 80), | |
| data = d3.range(2000).map(function() { return [randomX(), randomY()]; }); | |
| draw(); | |
| function zoom() { | |
| var transform = d3.event.transform; | |
| context.save(); | |
| context.clearRect(0, 0, width, height); | |
| context.translate(transform.x, transform.y); | |
| context.scale(transform.k, transform.k); | |
| draw(); | |
| context.restore(); | |
| } | |
| function draw() { | |
| var i = -1, n = data.length, d; | |
| context.beginPath(); | |
| while (++i < n) { | |
| d = data[i]; | |
| context.moveTo(d[0], d[1]); | |
| context.arc(d[0], d[1], 2.5, 0, 2 * Math.PI); | |
| } | |
| context.fill(); | |
| } | |
| </script> |
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