| <!DOCTYPE html> |
| <meta name="viewport" content="width=device-width, user-scalable=no"> |
| <link rel="stylesheet" type="text/css" href="resources/tablet.css"> |
| <script src="resources/perf_test_helper.js"></script> |
| <style> |
| target { |
| -webkit-animation: 1000ms linear; |
| } |
| </style> |
| |
| <container id="container"></container> |
| |
| <script> |
| var N = PerfTestHelper.getN(1000); |
| var duration = 1000; |
| var targets = []; |
| var styles = []; |
| |
| for (var i = 0; i < N; i++) { |
| var target = document.createElement('target'); |
| container.appendChild(target); |
| targets.push(target); |
| } |
| |
| function addNewAnimationStyle(step) { |
| // Clean up overwritten styles. |
| var i = 0; |
| for (; i < styles.length && styles[i].lastStep < step; i++) { |
| styles[i].style.remove(); |
| } |
| styles.splice(0, i); |
| |
| var style = document.createElement('style'); |
| var animationName = 'anim' + step; |
| style.textContent = '@-webkit-keyframes ' + animationName + ' { 0% { opacity: 0; } 100% { opacity: 1; } }'; |
| container.appendChild(style); |
| styles.push({ |
| style: style, |
| lastStep: step + N, |
| }); |
| |
| return animationName; |
| } |
| |
| function startAnimations(startingTargets, startStep, endStep) { |
| var newAnimationName = addNewAnimationStyle(startStep, endStep); |
| startingTargets.forEach(function(startInfo) { |
| startInfo.target.style.animationName = newAnimationName; |
| startInfo.target.style.animationDelay = -startInfo.fastForward + 'ms'; |
| }); |
| } |
| |
| requestAnimationFrame(function(time) { |
| var startTime = time - duration; |
| var previousStep = 0; |
| |
| function staggeredStart(time) { |
| var elapsed = time - startTime; |
| var targetStep = Math.floor(N * elapsed / duration); |
| var restartingTargets = []; |
| for (var step = Math.max(targetStep - N, previousStep); step < targetStep; step++) { |
| var stepStartTime = step / N * duration; |
| restartingTargets.push({ |
| target: targets[step % N], |
| fastForward: elapsed - stepStartTime, |
| }); |
| } |
| startAnimations(restartingTargets, targetStep); |
| previousStep = targetStep; |
| requestAnimationFrame(staggeredStart); |
| } |
| staggeredStart(time); |
| |
| PerfTestHelper.signalReady(); |
| }); |
| </script> |
