canvas仿寫貝塞爾曲線的範例程式碼

天正在等煙雨，而我在等你，啦啦啦，歡迎關注我的簡書，今天分享的是原創的canvas仿寫貝塞爾曲線方法。具體如下：

效果圖：

html

 <canvas id=mycanvas width=500 height=500>您的瀏覽器不支援canvas</canvas>

css

 canvas{ border: 1px solid black;}

js

 var canvas = document.getElementById(mycanvas); var context = canvas.getContext(2d); var x1 = 100; var y1 = 100; var x2 = 400; var y2 = 400; draw(); /畫半透明的線context.beginPath(); context.moveTo(500,0); context.lineTo(0,500); context.strokeStyle = rgba(0,0,0,0.3); context.lineWidth = 10; context.stroke(); //畫連接線context. beginPath(); context.moveTo(0,500); context.lineTo(x1,y1); context.lineWidth = 2; context.strokeStyle = black; context.stroke(); context.beginPath(); context.moveTo(500,0); context.lineTo(x2,y2); context.lineWidth = 2; context.strokeStyle = black ; context.stroke(); //畫紅球context.beginPath(); context.arc(x1,y1,10,0,Math.PI*2); context.fillStyle = orange; context.fill(); //畫藍球context.beginPath(); context.arc(x2,y2, 10,0,Math.PI*2); context.fillStyle = blue; context.fill(); //畫貝塞爾曲線context.beginPath(); context.moveTo(0,500); context.bezierCurveTo(x1,y1,x2,y2,500,0); context.lineWidth = 5; context.stroke(); } //拖曳小球做動畫//判斷是否拖曳動小球//如果在小球上就做動畫canvas.onmousedown = function(e){ var ev = e || window.event; var x = ev.offsetX; var y = ev.offsetY; //判斷是否在紅球上var dis = Math.pow((x-x1),2) + Math.pow((y-y1),2) ; if(dis<100){ console.log(滑鼠在紅球上); canvas.onmousemove = function(e){ var ev = e || window.event; var xx = ev.offsetX; var yy = ev.offsetY; //清除畫布context.clearRect(0,0,canvas.width,canvas.height); x1 = xx; y1 = yy; //重繪製draw() ; } } //判斷滑鼠是否在藍球上var dis = Math.pow((x-x2),2) + Math.pow((y-y2),2); if(dis<100){ canvas.onmousemove = function(e){ var ev = e || window.event; var xx1 = ev.offsetX; var yy1 = ev .offsetY; //清除畫布context.clearRect(0,0,canvas.width,canvas.height); x2 = xx1; y2 = yy1; //重繪製draw(); } } } document.onmouseup =function(){ canvas.onmousemove = ; }

以上就是本文的全部內容，希望對大家的學習有所幫助，也希望大家多多支持VeVb武林網。