implement pinch to zoom

node_modules/component-tween/examples/circle.html

@@ -0,0 +1,45 @@
+
+<style>
+  canvas {
+    border: 1px solid #eee;
+  }
+</style>
+
+<script src="../build/build.js"></script>
+
+<canvas width=500 height=400></canvas>
+
+<button onclick='tween.stop()'>Stop</button>
+
+<script>
+  var Tween = require('tween');
+  var raf = require('component-raf');
+  var canvas = document.querySelector('canvas');
+  var ctx = canvas.getContext('2d');
+
+  var tween = Tween({ alpha: 0, border: 1, radius: 1 })
+    .ease('out-bounce')
+    .to({ alpha: 1, border: 15, radius: 150  })
+    .duration(1000);
+
+  tween.update(function(o){
+    canvas.width = canvas.width;
+    ctx.strokeStyle = 'black';
+    ctx.globalAlpha = o.alpha;
+    ctx.lineWidth = o.border;
+    ctx.arc(canvas.width / 2, canvas.height / 2, o.radius, 0, Math.PI * 2, false);
+    ctx.stroke();
+    ctx.fill();
+  });
+
+  tween.on('end', function(){
+    animate = function(){};
+  });
+
+  function animate() {
+    raf(animate);
+    tween.update();
+  }
+
+  animate();
+</script>