【www.bbyears.com--html5教程】
HTML5的使用对大家来说还是比较有意思的,大家可以使用其制作很多独特的效果。那么你们知道使用HTML5怎么实现时钟缩放吗?这次文章就给大家介绍下HTML5实现时钟缩放的代码,感兴趣的下面一起来看看。
canvas_time <script type="text/JavaScript" > var dom = document.getElementById("clock"); var ctx = dom.getContext("2d"); var width = ctx.canvas.width; var height = ctx.canvas.height; var r = width / 2; var rem = width/200; function drawBackground() { ctx.save(); //存储当前环境变量; ctx.translate(r, r); //重置坐标到r,r ctx.beginPath(); // 起始一条路径 ctx.lineWidth = 10*rem; //设置线宽10; ctx.arc(0, 0, r - ctx.lineWidth /2, 0, 2 * Math.PI, false); ctx.stroke(); var hourNumbers = [3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 1, 2]; //定义数组 ctx.font = 18*rem+"px Arial"; ctx.textAlign = "center"; ctx.textBaseline = "middle"; hourNumbers.forEach(function(number, i) { var rad = 2 * Math.PI / 12 * i; var x = Math.cos(rad) * (r - 30*rem); var y = Math.sin(rad) * (r - 30*rem); ctx.fillText(number, x, y); }); for (var i = 0; i < 60; i++) { var rad = 2 * Math.PI / 60 * i; var x = Math.cos(rad) * (r - 18*rem); var y = Math.sin(rad) * (r - 18*rem); ctx.beginPath(); if (i % 5 === 0) { ctx.arc(x, y, 2*rem, 0, 2 * Math.PI, false); ctx.fillStyle = "#000"; } else { ctx.arc(x, y, 2*rem, 0, 2 * Math.PI, false); ctx.fillStyle = "#ccc"; } ctx.fill(); } } function drawHour(hour, minute) { ctx.save(); ctx.beginPath(); var rad = 2 * Math.PI / 12 * hour; var mrad = 2 * Math.PI / 12 / 60 * minute; ctx.rotate(rad + mrad); ctx.lineWidth = 6*rem; ctx.lineCap = "round"; ctx.moveTo(0, 10*rem); ctx.lineTo(0, -r / 2); ctx.stroke(); ctx.restore(); } function drawMinute(minute) { ctx.save(); ctx.beginPath(); var rad = 2 * Math.PI / 60 * minute; ctx.rotate(rad); ctx.lineWidth = 3*rem; ctx.lineCap = "round"; ctx.moveTo(0, 10*rem); ctx.lineTo(0, -r + 30*rem); ctx.stroke(); ctx.restore(); } function drawSecond(second) { ctx.save(); ctx.beginPath(); ctx.fillStyle = "red"; var rad = 2 * Math.PI / 60 * second; ctx.rotate(rad); ctx.moveTo(-2*rem, 20*rem); ctx.lineTo(2*rem, 20*rem); ctx.lineTo(1, -r + 16*rem); ctx.lineTo(-1, -r + 16*rem); ctx.fill(); ctx.restore(); } function drawDot() { ctx.beginPath(); ctx.fillStyle = "#fff"; ctx.arc(0, 0, 3*rem, 0, 2 * Math.PI, false); ctx.fill(); } function draw01() { ctx.clearRect(0, 0, width, height); var now = new Date(); var hour = now.getHours(); var minute = now.getMinutes(); var second = now.getSeconds(); drawBackground(); drawHour(hour, minute); drawMinute(minute); drawSecond(second); drawDot(); ctx.restore(); } draw01(); setInterval(draw01, 1000); </script>