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added another js montrosity

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TomHodson 2012-10-08 22:22:06 +01:00
parent fabba39e5f
commit 9cf9f9ebd8
1 changed files with 93 additions and 0 deletions
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factordiagram.html Normal file
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<html>
<canvas id="canvas"></canvas>
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.8.2/jquery.min.js"></script>
<script src="./underscore/underscore.js"></script>
<script type="text/javascript">
var canvas = $("#canvas")[0];
var context = canvas.getContext("2d");
canvas.width = innerWidth;
canvas.height = innerHeight * 3;
prettytiles();
function prettytiles() {
var box_width = 100;
var n_rows = Math.floor(canvas.width / box_width);
context.translate(box_width,box_width);
for (var i = 0; i < 100; i++) {
var x = (i%n_rows)*box_width;
var y = Math.floor(i / n_rows) * box_width;
context.translate(x,y);
context.scale(box_width/2, box_width/2);
factordiagram(primefactors(i+1)).draw();
context.scale(1/(box_width/2), 1/(box_width/2));
context.translate(-x,-y);
};
}
function factordiagram(factors) {
if(factors.length == 0) { //there are no factors left, we're at the bottom; draw a little dot
return {
draw: function() {
context.beginPath();
context.arc(0,0,1,0,2*Math.PI);
context.stroke();
context.fill();
},
width : 1,
height : 1
}
}
else {
var factor = factors.pop();
var subunit = factordiagram(factors);
return {
draw : function() {
var radius = 0.5;
var ang_step = 2*Math.PI/factor;
var scale = (2*Math.PI*radius) / (4*factor);
for (var i = 0; i < factor; i++) {
var x = radius * Math.sin(i * ang_step); var y = radius * Math.cos(i * ang_step);
context.translate(x,y);
context.scale(scale, scale);
if(factor == 2) context.rotate(Math.PI/2);
subunit.draw();
if(factor == 2) context.rotate(-Math.PI/2);
context.scale(1/scale, 1/scale);
context.translate(-x,-y);
};
}
}
}
}
function primesupto(x) {
notprimes = Array();
primes = Array();
for (var i = 2; i <= x; i++) {
if(notprimes.indexOf(i) == -1) {
primes.push(i);
notprimes = _.union(notprimes, _.range(0,x+1,i));
};
};
return primes;
}
function primefactors(x) {
if(x == 1) { return []; }
primes = primesupto(x);
for (var i = 0; i < primes.length; i++) {
if(x % primes[i] == 0) {
return [primes[i]].concat(primefactors(x/primes[i]));
}
};
}
</script>
</html>