html5如何在Canvas中实现自定义路径动画示例

2019-01-28 13:14:09王冬梅

function customizePath(path, func) { const pathElement = document.createElementNS('http://www.w3.org/2000/svg',"path"); pathElement.setAttributeNS(null, 'd', path); const length = pathElement.getTotalLength(); const duration = 1000; const interval = length / duration; let time = 0, step = 0; const timer = setInterval(function() { if (time <= duration) { const x = parseInt(pathElement.getPointAtLength(step).x); const y = parseInt(pathElement.getPointAtLength(step).y); func(x, y); step++; } else { clearInterval(timer) } }, interval); } const path = 'M0,0 C8,33.90861 25.90861,16 48,16 C70.09139,16 88,33.90861 88,56 C88,78.09139 105.90861,92 128,92 C150.09139,92 160,72 160,56 C160,40 148,24 128,24 C108,24 96,40 96,56 C96,72 105.90861,92 128,92 C154,93 168,78 168,56 C168,33.90861 185.90861,16 208,16 C230.09139,16 248,33.90861 248,56 C248,78.09139 230.09139,96 208,96 L48,96 C25.90861,96 8,78.09139 8,56 Z'; const canvas = document.querySelector('canvas'); const context = canvas.getContext('2d'); function move(x, y) { context.clearRect(0, 0, canvas.width, canvas.height); context.beginPath(); context.arc(x, y, 25, 0, Math.PI*2, true); context.fillStyle = '#f0f'; context.fill(); context.closePath(); } customizePath(path, move);

实现思路大致如上所述,然而这并不是最终成果。当我们决定要在canvas制作自定义路径动画时,我们不仅要考虑如何实现,更要考虑性能优化,比如在这个实现思路中,我们是否可以减少不必要的渲染次数?帧率如何控制达到最优?等等。

虽然它们并不在这篇文章的讨论范围中,当也应当值得我们思考。

以上就是本文的全部内容,希望对大家的学习有所帮助,也希望大家多多支持易采站长站。