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问题:
For a personal project, I'm tyring to make a timer application (for controlling Poker blind schedules). I know there are several solutions already on the market, but for reasons which are too lengthy to go into here, we need a bespoke system. Although the output template of the system will ultimately be definable by the end user, we would like to include a widget which shows a circle that gets animated as the time counts down. Here's an illustration of a working example, showing the yellow circle and what we'd like to achieve (or something similar, anyway):
My question is, how would one code the animation as shown below using either jQuery or raw HTML5 / CSS3 animations? This is for a web application using jQuery, so there are no other library options I can use.
Advanced thanks!
回答1:
If you can use HTML5, canvas is probably your best bet. Mozilla has some decent tutorials on drawing arcs. This should be enough to get you started.
var canvas = document.getElementById('canvasid'), width = canvas.width, height = canvas.height, ctx = canvas.getContext('2d'); function drawTimer(deg) { var x = width / 2, // center x y = height / 2, // center y radius = 100, startAngle = 0, endAngle = deg * (Math.PI/180), counterClockwise = true; ctx.clearRect(0, 0, height, width); ctx.save(); ctx.fillStyle = '#fe6'; // Set circle orientation ctx.translate(x, y); ctx.rotate(-90 * Math.PI/180); ctx.beginPath(); ctx.arc(0, 0, radius, startAngle, endAngle, counterClockwise); ctx.lineTo(0, 0); ctx.fill(); } setInterval(function() { // Determine the amount of time elapsed; converted to degrees var deg = (elapsedTime / totalTime) * 360; drawTimer(deg); }, 1000);
回答2:
You can achieve this with CSS3 and jQuery.
Check out my example here http://blakek.us/css3-pie-graph-timer-with-jquery/ which with slight modification you could make the timer look how you want it.
回答3:
In HTML5 you can draw in a canvas. For example:
// Create the yellow face context.strokeStyle = "#000000"; context.fillStyle = "#FFFF00"; context.beginPath(); context.arc(100,100,50,0,Math.PI*2,true); context.closePath(); context.stroke(); context.fill();
Link
回答4:
You should really check out Processing!
Especially Processing.js. There have been some interesting things made with it for iPhone
回答5:
First solution i can think of is html5 canvas implementation. From the example above it becomes clear we're talking mobile, so what support does canvas get around mobile browsers i can't tell. developer.mozilla.org provides sufficient documentation. Using canvas to achieve such count down should be pretty simple task. Good luck.
回答6:
HTML5 Canvas arc command (MDN) is probably what you're looking for. Just decrease the end angle over time to have your timer decrease.
