coldshine.github.com/canvas.html at master · coldshine/coldshine.github.com · GitHub

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<html>
  <head>
    <title>Canvas tutorial template</title>
	<script type="text/javascript" src="js/classes/dbg.js"></script>
	<script type="text/javascript" src="js/classes/tools.js"></script>
	<script type="text/javascript" src="js/classes/draw.js"></script>
    <script type="text/javascript">
		var ctx;
		function init() {
			ctx = document.getElementById('canvas').getContext('2d');
			timeline.do();
		}

		//this is a general class
		var timeline = {
			currentFrame: 0,
			fps: 24, //frame per second
			//play_animation: true,
			debug: true,
			in_progress: false, //if true we should continue loop
			center_point: {x:175, y:175} //default center point of all objects
		};

		timeline.do = function(){
			var _instance = this;
			this.currentFrame++;
			ctx.clearRect(0,0,500,500);

			if(this.debug)
				dbg.draw("currentFrame = "+this.currentFrame);

			//First arc
			var arParams = {
				angle:{start:285,end:255},
				second:{start:1,length:1},
				radius:50
			}
			draw.doubleArc(arParams);

			//First arc text
			var arParams = {
				point:{x:166, y:130},
				second:{start:2},
				text: "1/2"
			}
			draw.text(arParams);

			//Second arc
			var arParams = {
				angle:{start:190,end:170},
				second:{start:2,length:1},
				radius:60
			}
			draw.doubleArc(arParams);

			//Second arc text
			var arParams = {
				point:{x:166, y:-175+61},
				second:{start:3},
				text: "1/4",
				rotate: 90
			}
			draw.text(arParams);

            //Third arc
            var arParams = {
                angle:{start:100,end:80},
                second:{start:3,length:1},
                radius:70
            }
            draw.doubleArc(arParams);

            //Third arc text
            var arParams = {
                point:{x:167, y:175+70},
                second:{start:4},
                text: "1/8"
            }
            draw.text(arParams);

			//Fourth circle
            var arParams = {
                angle:{start:90,end:90},
                second:{start:3.5,length:1},
                radius:80
            }
			draw.doubleArc(arParams);

            var arParams = {
                point:{x:400,y:175},
                second:{start:5,length:3},
            }
			draw.moveCenterPointX(arParams);

			//loop
			if(this.in_progress){
				setTimeout(function(){
					_instance.do()
				}, parseInt(1000/_instance.fps));
			}
		}

		timeline.getFrameData = function(arParams){

			this.in_progress = false;

			var frame = {};
			frame.current = {};

			frame.current.global = this.currentFrame;

			//convert starting second to frame
			if(arParams.second.start){
				frame.start = arParams.second.start * this.fps;
				frame.current.local = frame.current.global - frame.start;
			}

			//wait for animation time
			if(frame.current.global < frame.start){
				this.in_progress = true;
				return false;
			}

			//convert endinf second to frame
			if(arParams.second.start && arParams.second.length){
				frame.end = (arParams.second.start + arParams.second.length) * this.fps;
				frame.diff = frame.end - frame.start;
			} else {
				frame.end = frame.start;
				frame.diff = 0;
			}

			//if last frame has been played
			if(frame.current.global <= frame.end){
				this.in_progress = true;
			}

			return frame;
		}

	</script>
    <style type="text/css">
      canvas { border: 2px solid black; }
    </style>
  </head>
  <body onload="init();">
    <canvas id="canvas" width="900" height="500"></canvas>
  </body>
</html>