HTML5 Canvas 优化动画性能提示

如果你的动画有帧没有任何更新（没有节点被更改），你可以在动画函数中 return false。

在这种情况下，Konva 将不会更新图层。

Konva Optimize Animation Demoview raw

<!DOCTYPE html>
<html>
  <head>
    <script src="https://unpkg.com/konva@9.3.18/konva.min.js"></script>
    <meta charset="utf-8" />
    <title>Konva Optimize Animation Demo</title>
    <style>
      body {
        margin: 0;
        padding: 0;
        overflow: hidden;
        background-color: #f0f0f0;
      }
    </style>
  </head>
  <body>
    <div id="container"></div>
    <script>
      var width = window.innerWidth;
      var height = window.innerHeight;

      var stage = new Konva.Stage({
        container: 'container',
        width: width,
        height: height,
      });

      var layer = new Konva.Layer();

      var hexagon = new Konva.RegularPolygon({
        x: stage.width() / 2,
        y: stage.height() / 2,
        sides: 6,
        radius: 20,
        fill: 'red',
        stroke: 'black',
        strokeWidth: 4,
      });

      layer.add(hexagon);
      stage.add(layer);

      var amplitude = 100;
      var period = 2000;
      // in ms
      var centerX = stage.width() / 2;

      // we have animation that do nothing in some cases
      var anim = new Konva.Animation(function (frame) {
        if (frame.time % (period * 2) < period) {
          // regular update
          hexagon.x(
            amplitude * Math.cos((frame.time * 2 * Math.PI) / period) + centerX
          );
        } else {
          // this is "pause" phase
          // we don't need update layer in this case
          // so return false and Konva will skip layer draw
          return false;
        }
      }, layer);

      anim.start();
    </script>
  </body>
</html>