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A game show/board game style spinner, made with SVG and JavaScript. Add some data to the "Slice" objects and make something useful out of it.
<!DOCTYPE HTML>
<html>
<head>
<title>SVG Spinner</title>
<style type="text/css">
* {
font-family: Arial, sans-serif;
}
#wrapper {
width: 400px;
text-align: center;
}
#button-holder {
width: 200px;
margin: auto;
}
#spinner-button {
width: 200px;
height: 75px;
font-size: 1.25em;
font-weight: bold;
}
</style>
<script type="text/javascript">
var svgns = "http://www.w3.org/2000/svg"; // SVG Namespace (in case we need it)
var slices = []; // Array of wheel slice objects
var numSlices = 6; // Size of the circle slices
var isSpinning = false; // Is the arrow spinning?
var rotation = 0; // Arrow rotation
var currentSlice = 0; // Current slice the arrow is over
var wheel; // DOM Object for the spinner board
var arrow; // DOM Object for the spinner arrow
var spinButton; // DOM Object for the spin wheel <button>
// Basic wheel "slice" object for drawing SVG
function Slice(num, parent) {
// Set instance vars
this.parent = parent;
this.size = 360/numSlices;
this.offset = num * this.size;
this.id = "slice_"+num;
// Draw the object
this.object = this.create();
this.parent.appendChild(this.object);
}
Slice.prototype = {
create:function() {
// Create a group to store the slice in
var g = document.createElementNS(svgns, "g");
// Create the slice object
var slice = document.createElementNS(svgns, "path");
slice.setAttributeNS(null, "id", this.id);
var x1 = 200 + 180 * Math.cos(Math.PI*(-90+this.offset)/180);
var y1 = 200 + 180 * Math.sin(Math.PI*(-90+this.offset)/180);
var x2 = 200 + 180 * Math.cos(Math.PI*(-90+this.size+this.offset)/180);
var y2 = 200 + 180 * Math.sin(Math.PI*(-90+this.size+this.offset)/180);
slice.setAttributeNS(null, "d", "M 200 200 L "+x1+" "+y1+" A 180 180 0 0 1 "+x2+" "+y2+" Z");
// Randomize the color of the slice and finish styling
var red = Math.floor(Math.random() * 215) + 20;
var green = Math.floor(Math.random() * 215) + 20;
var blue = Math.floor(Math.random() * 215) + 20;
slice.setAttributeNS(null, "fill", "rgb("+red+","+green+","+blue+")");
slice.setAttributeNS(null, "stroke", "#222222");
slice.setAttributeNS(null, "style", "stroke-width:2px");
// Add the slice to the group
g.appendChild(slice);
// Create the highlight for the slice
var overlay = document.createElementNS(svgns, "path");
overlay.setAttributeNS(null, "d", "M 200 200 L "+x1+" "+y1+" A 180 180 0 0 1 "+x2+" "+y2+" Z");
overlay.setAttributeNS(null, "fill", "#FFFFFF");
overlay.setAttributeNS(null, "stroke", "#222222");
overlay.setAttributeNS(null, "style", "stroke-width:1px");
overlay.setAttributeNS(null, "opacity", "0");
// Add the highlight for the slice to the group
g.appendChild(overlay);
return g;
},
toggleOverlay:function() {
var overlay = this.object.childNodes[1];
if (overlay.getAttribute("opacity") == 0) {
overlay.setAttributeNS(null, "opacity", 1);
}
else {
overlay.setAttributeNS(null, "opacity", 0);
}
}
};
// Toggle the spinning of the wheel
function toggleSpinning() {
// Toggle the spinning animation
if (isSpinning) {
// Stop the arrow
isSpinning = false;
clearInterval(toggleSpinning.spinInt);
spinButton.removeAttribute("disabled");
}
else {
// Start spinning the arrow
isSpinning = true;
toggleSpinning.spinInt = setInterval(spinWheel, 1000/60);
// Set how long the wheel will be spinning
var duration = Math.floor(Math.random() * 2000) + 1000;
setTimeout(toggleSpinning, duration);
// Disable the spin button
spinButton.setAttribute("disabled", "true");
}
}
// Animation step for spinning the wheel arrow
function spinWheel() {
// Rotate the spinner arrow
rotation = (rotation + 12) % 360;
arrow.setAttributeNS(null, "transform", "rotate("+rotation+",200,200)");
// Highlight the slice the arrow is above
var newSlice = Math.floor(rotation / (360/numSlices));
if (newSlice != currentSlice) {
slices[currentSlice].toggleOverlay();
slices[newSlice].toggleOverlay();
currentSlice = newSlice;
}
}
// Document ready event
document.addEventListener("DOMContentLoaded", function() {
// Get a handle to all necessary DOM elements
wheel = document.getElementById("spinner-board"); // DOM Object for the spinner board
arrow = document.getElementById("spinner-arrow"); // DOM Object for the spinner arrow
spinButton = document.getElementById("spinner-button"); // DOM Object for the spin wheel <button>
// Generate the wheel sections
for (var i = 0; i < numSlices; i++) {
slices[i] = new Slice(i, wheel);
}
// Highlight the first slice
slices[0].toggleOverlay();
}, false);
</script>
</head>
<body>
<div id="wrapper">
<svg xmlns="http://www.w3.org/2000/svg" version="1.1" width="400" height="400">
<circle cx="200" cy="200" r="180" fill="#222222"/>
<g id="spinner-board"></g>
<path id="spinner-arrow" d="M 195 200 L 195 70 L 188 70 L 200 55 L 212 70 L 205 70 205 200 Z" fill="#EEEEEE" stroke="#222222" style="stroke-width:2px"/>
<circle cx="200" cy="200" r="18" fill="#444444" stroke="#222222" style="stroke-width:2px"/>
<circle cx="200" cy="200" r="9" fill="#666666" stroke="#222222" style="stroke-width:2px"/>
</svg>
<div id="button-holder">
<button id="spinner-button" onclick="toggleSpinning();">Start the Spinner!</button>
</div>
</div>
</body>
</html>
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