时间:2021-07-01 10:21:17 帮助过:124人阅读
代码实现的一种方法
- <!DOCTYPE html>
- <html lang="en">
- <head>
- <meta charset="UTF-8">
- <title>使用桃心形方程绘制爱心</title>
- </head>
- <body>
- <canvas></canvas>
- <script>
- var canvas = document.querySelector('canvas');
- var ctx = canvas.getContext('2d');
- canvas.width = window.innerWidth;
- canvas.height = window.innerHeight;
- var Heart = function(x, y) {
- this.x = x;
- this.y = y;
- this.vertices = [];
- for(let i=0; i<30; i++) {
- var step = i / 30 * (Math.PI * 2);//设置心上面两点之间的角度,具体分成多少份,好像需要去试。
- var vector = {
- x : (15 * Math.pow(Math.sin(step), 3)),
- y : -(13 * Math.cos(step) - 5 * Math.cos(2 * step) - 2 * Math.cos(3 * step) - Math.cos(4 * step))
- }
- this.vertices.push(vector);
- }
- }
- Heart.prototype.draw = function() {
- ctx.translate(-1000,this.y);//这一步跟ctx.shadowOffsetX必须一起使用,不明白为啥?
- ctx.beginPath();
- for(let i=0; i<30; i++) {
- var vector = this.vertices[i];
- ctx.lineTo(vector.x, vector.y);
- }
- ctx.shadowColor = "red";
- ctx.shadowOffsetX = this.x+1000;
- ctx.fill();
- }
- canvas.onmousedown = function(e) {
- var x = e.offsetX;
- var y = e.offsetY;
- var heart = new Heart(x, y);
- heart.draw();
- }
- </script>
- </body>
- </html>
以上就是html5 canvas绘制爱心的方法示例的详细内容,更多请关注Gxl网其它相关文章!