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<head>
<meta charset="utf-8">
</script>
</head>
<body>
<center>
<h1 style="color: green;">
Geeksforgeeks
</h1>
<h3>D3.js | transform.scale() Function</h3>
<canvas width="500" height="300"></canvas>
<script>
var canvas = d3.select("canvas"),
context = canvas.node().getContext("2d"),
width = canvas.property("width"),
height = canvas.property("height"),
radius = 2.5;
var points = d3.range(300).map(phyllotaxis(10)),
point = points.pop();
var zoom = d3.zoom()
.on("zoom", zoomed);
canvas
.call(zoom.transform, transform)
.call(transition);
function zoomed() {
context.save();
context.clearRect(0, 0, width, height);
context.translate(d3.event.transform.x,
d3.event.transform.y);
context.scale(d3.event.transform.k,
d3.event.transform.k);
drawPoints();
context.restore();
}
function drawPoints() {
context.beginPath();
points.forEach(drawPoint);
context.fillStyle = "#8d0396";
context.fill();
context.beginPath();
drawPoint(point);
context.fillStyle = "#00ab1c";
context.fill();
context.stroke();
}
function drawPoint(point) {
context.moveTo(point[0] + radius, point[1]);
context.arc(point[0], point[1],
radius, 0, 2 * Math.PI);
}
function transform() {
return d3.zoomIdentity
.translate(width / 2, height / 2)
.scale(8)
.translate(-point[0], -point[1]);
}
function transition(canvas) {
var n = points.length,
i = Math.random() * n | 0,
c = points[i]; // Pick a random point.
points[i] = points[n - 1];
points[n - 1] = point;
point = c;
canvas.transition()
.delay(500)
.duration(3000)
.call(zoom.transform, transform)
.on("end", function ()
{ canvas.call(transition); });
}
function phyllotaxis(radius) {
var theta = Math.PI * (3 - Math.sqrt(5));
return function (i) {
var r = radius * Math.sqrt(i),
a = theta * i;
return [
width / 2 + r * Math.cos(a),
height / 2 + r * Math.sin(a)
];
};
}
</script>
</center>
</body>
</html>