Learning Web Design - Canvas Clock code

Canvas Clock code

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<!DOCTYPE html>

<html>

<body>

<canvas id="canvas" width="400" height="400"

style="background-color:#333">

</canvas>

var canvas = document.getElementById("canvas");

var ctx = canvas.getContext("2d");

var radius = canvas.height / 2;

ctx.translate(radius, radius);

radius = radius * 0.90

setInterval(drawClock, 1000);

function drawClock() {

drawFace(ctx, radius);

drawNumbers(ctx, radius);

drawTime(ctx, radius);

}

function drawFace(ctx, radius) {

var grad;

ctx.beginPath();

ctx.arc(0, 0, radius, 0, 2*Math.PI);

ctx.fillStyle = 'white';

ctx.fill();

grad = ctx.createRadialGradient(0,0,radius*0.95, 0,0,radius*1.05);

grad.addColorStop(0, '#333');

grad.addColorStop(0.5, 'white');

grad.addColorStop(1, '#333');

ctx.strokeStyle = grad;

ctx.lineWidth = radius*0.1;

ctx.stroke();

ctx.beginPath();

ctx.arc(0, 0, radius*0.1, 0, 2*Math.PI);

ctx.fillStyle = '#333';

ctx.fill();

}

function drawNumbers(ctx, radius) {

var ang;

var num;

ctx.font = radius*0.15 + "px arial";

ctx.textBaseline="middle";

ctx.textAlign="center";

for(num = 1; num < 13; num++){

ang = num * Math.PI / 6;

ctx.rotate(ang);

ctx.translate(0, -radius*0.85);

ctx.rotate(-ang);

ctx.fillText(num.toString(), 0, 0);

ctx.rotate(ang);

ctx.translate(0, radius*0.85);

ctx.rotate(-ang);

}

function drawTime(ctx, radius){

var now = new Date();

var hour = now.getHours();

var minute = now.getMinutes();

var second = now.getSeconds();

//hour

hour=hour%12;

hour=(hour*Math.PI/6)+

(minute*Math.PI/(6*60))+

(second*Math.PI/(360*60));

drawHand(ctx, hour, radius*0.5, radius*0.07);

//minute

minute=(minute*Math.PI/30)+(second*Math.PI/(30*60));

drawHand(ctx, minute, radius*0.8, radius*0.07);

// second

second=(second*Math.PI/30);

drawHand(ctx, second, radius*0.9, radius*0.02);

}

function drawHand(ctx, pos, length, width) {

ctx.beginPath();

ctx.lineWidth = width;

ctx.lineCap = "round";

ctx.moveTo(0,0);

ctx.rotate(pos);

ctx.lineTo(0, -length);

ctx.stroke();

ctx.rotate(-pos);

}

</script>

</body>

</html>