<!DOCTYPE html>

<html ng-app="APP">

<head>

    <meta charset="UTF-8">

  <script src="http://cdn.bootcss.com/angular.js/1.3.0-beta.12/angular.min.js"></script>

</head>

<body ng-controller="MainCtrl">

  <!--

    界面的這個元素會被替換成canvas元素;

  -->

    <div ang:round:progress data-round-progress-model="roundProgressData"></div>

    <br>

    <input type="number" ng-model="roundProgressData.label"/>

    <script>

                                   //引用angular.directives-round-progress這個模塊;

     var APP = angular.module('APP', ['angular.directives-round-progress']).

     controller('MainCtrl', function($scope) {

        $scope.roundProgressData = {

          //這個是初始化的數(shù)據(jù);

          label: 11,

          percentage: 0.11

        }

        //通過監(jiān)聽scope下的這個roundProgressData屬性, 對界面的canvas進(jìn)行重繪;

        $scope.$watch('roundProgressData', function (newValue) {

          newValue.percentage = newValue.label / 100;

        }, true);

      });

    </script>

<script>

    /*!

 * AngularJS Round Progress Directive

 *

 * Copyright 2013 Stephane Begaudeau

 * Released under the MIT license

 */

angular.module('angular.directives-round-progress', []).directive('angRoundProgress', [function () {

  var compilationFunction = function (templateElement, templateAttributes, transclude) {

    if (templateElement.length === 1) {

      //初始化DOM模型, 包括初始化canvas等;

      var node = templateElement[0];

      var width = node.getAttribute('data-round-progress-width') || '400';

      var height = node.getAttribute('data-round-progress-height') || '400';

      var canvas = document.createElement('canvas');

      canvas.setAttribute('width', width);

      canvas.setAttribute('height', height);

      canvas.setAttribute('data-round-progress-model', node.getAttribute('data-round-progress-model'));

        //相當(dāng)于demo, 替換原來的元素;

      node.parentNode.replaceChild(canvas, node);

        //各種配置;

      var outerCircleWidth = node.getAttribute('data-round-progress-outer-circle-width') || '20';

      var innerCircleWidth = node.getAttribute('data-round-progress-inner-circle-width') || '5';

      var outerCircleBackgroundColor = node.getAttribute('data-round-progress-outer-circle-background-color') || '#505769';

      var outerCircleForegroundColor = node.getAttribute('data-round-progress-outer-circle-foreground-color') || '#12eeb9';

      var innerCircleColor = node.getAttribute('data-round-progress-inner-circle-color') || '#505769';

      var labelColor = node.getAttribute('data-round-progress-label-color') || '#12eeb9';

      var outerCircleRadius = node.getAttribute('data-round-progress-outer-circle-radius') || '100';

      var innerCircleRadius = node.getAttribute('data-round-progress-inner-circle-radius') || '70';

      var labelFont = node.getAttribute('data-round-progress-label-font') || '50pt Calibri';

      return {

        pre: function preLink(scope, instanceElement, instanceAttributes, controller) {

          var expression = canvas.getAttribute('data-round-progress-model');

            //監(jiān)聽模型, O了

            //就監(jiān)聽一個屬性;

          scope.$watch(expression, function (newValue, oldValue) {

            // Create the content of the canvas

            //包括新建和重繪;

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

            ctx.clearRect(0, 0, width, height);

            // The "background" circle

            var x = width / 2;

            var y = height / 2;

            ctx.beginPath();

            ctx.arc(x, y, parseInt(outerCircleRadius), 0, Math.PI * 2, false);

            ctx.lineWidth = parseInt(outerCircleWidth);

            ctx.strokeStyle = outerCircleBackgroundColor;

            ctx.stroke();

            // The inner circle

            ctx.beginPath();

            ctx.arc(x, y, parseInt(innerCircleRadius), 0, Math.PI * 2, false);

            ctx.lineWidth = parseInt(innerCircleWidth);

            ctx.strokeStyle = innerCircleColor;

            ctx.stroke();

            // The inner number

            ctx.font = labelFont;

            ctx.textAlign = 'center';

            ctx.textBaseline = 'middle';

            ctx.fillStyle = labelColor;

            ctx.fillText(newValue.label, x, y);

            // The "foreground" circle

            var startAngle = - (Math.PI / 2);

            var endAngle = ((Math.PI * 2 ) * newValue.percentage) - (Math.PI / 2);

            var anticlockwise = false;

            ctx.beginPath();

            ctx.arc(x, y, parseInt(outerCircleRadius), startAngle, endAngle, anticlockwise);

            ctx.lineWidth = parseInt(outerCircleWidth);

            ctx.strokeStyle = outerCircleForegroundColor;

            ctx.stroke();

          }, true);

        },

        post: function postLink(scope, instanceElement, instanceAttributes, controller) {}

      };

    }

  };

  var roundProgress = {

      //compile里面先對dom進(jìn)行操作, 再對$socpe進(jìn)行監(jiān)聽;

    compile: compilationFunction,

    replace: true

  };

  return roundProgress;

}]);

</script>

</body>

</html>