knowledge/javascript/others/javascript.algorithms/canvas/selection_sort.html at master · TingGe/knowledge · GitHub

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<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <title>普通方式显示选择排序过程</title>
</head>

<body>
  <div style="margin:0 auto;width:900px;">
    <canvas id="myCanvas" width="900" height="600">Your browser dosen't support the canvas element.</canvas>
  </div>
  <script type="text/javascript">
    (function(window) {
      var canvas = document.getElementById("myCanvas");
      var ctx = canvas.getContext('2d');
      var height = canvas.height;
      var width = canvas.width;

      function getRandomNumber() {
        var result = parseInt(Math.random() * height);
        return result;
      }
      var lines = [];
      ctx.clearRect(0, 0, width, height);
      ctx.fillStyle = "#000000";
      ctx.fillRect(0, 0, width, height);
      ctx.lineWidth = 4;
      ctx.strokeStyle = "#999999";
      ctx.beginPath();
      for (var i = 1; i <= width; i += 9) {
        var tempHeight = getRandomNumber();
        //console.log("i: " + i + "height: " + height + "tempHeight: " + tempHeight) ;
        ctx.moveTo(i, height);
        ctx.lineTo(i, height - tempHeight);
        var line = {
          y: height - tempHeight,
          height: tempHeight
        }
        lines.push(line);
      }
      ctx.stroke();

      function repaint() {
        ctx.fillRect(0, 0, width, height);
        ctx.beginPath();
        var x = 1;
        for (var k = 1; k < lines.length; k++) {
          ctx.moveTo(x, height);
          ctx.lineTo(x, lines[k].y);
          x = x + 9;
        }
        ctx.stroke();
        console.log("repaint");
      }
      var i = 0;
      var j = 0;
      var N = lines.length;
      var min = i;
      setTimeout(function() {
        if (lines[min].height > lines[j].height) {
          var temp = lines[j];
          lines[j] = lines[min];
          lines[min] = temp;
          repaint();
        }
        j++;
        if (j == N) {
          i++;
          min = i;
          j = i + 1;
        }
        if (i < N - 1) {
          setTimeout(arguments.callee, 30);
        } else {
          var text = "";
          for (var l = 0; l < lines.length; l++) {
            text = text + lines[l].height + " ";
          }
          console.log(text);
        }
      }, 30);
    })(window);
  </script>
</body>

</html>