From 9cf9f9ebd8a1dc0bb953f3d9328a2be002c47e3d Mon Sep 17 00:00:00 2001
From: TomHodson <thomas.c.hodson@gmail.com>
Date: Mon, 8 Oct 2012 22:22:06 +0100
Subject: [PATCH] added another js montrosity

---
 factordiagram.html | 93 ++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 93 insertions(+)
 create mode 100644 factordiagram.html
diff --git a/factordiagram.html b/factordiagram.html
new file mode 100644
index 0000000..74f5b80
--- /dev/null
+++ b/factordiagram.html
@@ -0,0 +1,93 @@
+<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>
\ No newline at end of file
