這篇文章帶給大家的內容是關於canvas波浪效果的實現程式碼，有一定的參考價值，有需要的朋友可以參考一下，希望對你有幫助。 基於canvas的三次貝塞爾曲線(bezierCurveTo) var WAVE_HEIGHT = 200 //波浪变化高度 var SCALE = 0.5 // 绘制速率 var CYCLE = 360 / SCALE var TIME = 0 function initCanvas() { var c = document.getElementById("myCanvas") var width = window.screen.width var height = window.screen.height var ctx = c.getContext("2d") c.width = width c.height = height // start window.requestAnimationFrame(function() { draw(ctx, width, height) }) } function draw(ctx, width, height) { ctx.clearRect(0, 0, width, height) TIME = (TIME + 1) % CYCLE var angle = SCALE * TIME // 当前正弦角度 var dAngle = 60 // 两个波峰相差的角度 ctx.beginPath() ctx.moveTo(0, height * 0.5 + distance(WAVE_HEIGHT, angle, 0)) ctx.bezierCurveTo( width * 0.4, height * 0.5 + distance(WAVE_HEIGHT, angle, dAngle), width * 0.6, height * 0.5 + distance(WAVE_HEIGHT, angle, 2 * dAngle), width, height * 0.5 + distance(WAVE_HEIGHT, angle, 3 * dAngle) ) ctx.strokeStyle = "#ff0000" ctx.stroke() ctx.beginPath() ctx.moveTo(0, height * 0.5 + distance(WAVE_HEIGHT, angle, -30)) ctx.bezierCurveTo( width * 0.3, height * 0.5 + distance(WAVE_HEIGHT, angle, dAngle - 30), width * 0.7, height * 0.5 + distance(WAVE_HEIGHT, angle, 2 * dAngle - 30), width, height * 0.5 + distance(WAVE_HEIGHT, angle, 3 * dAngle - 30) ) ctx.strokeStyle = "#0000ff" ctx.stroke() function distance(height, currAngle, diffAngle) { return height * Math.cos((((currAngle - diffAngle) % 360) * Math.PI) / 180) } // animate window.requestAnimationFrame(function() { draw(ctx, width, height) }) } initCanvas() 登入後複製
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