在canvas中，可以使用clip()函数裁剪区域，设定裁剪区域后，只有在区域内的图像才能显示，其余部分会被屏蔽掉
未使用裁剪绘制一个圆
*{margin:0; padding:0;}
html, body{width:100%; height:100%; overflow:hidden; background-color:#AFAFAF;}
var canvas = document.getElementById('canvas'),
context = canvas.getContext('2d');
canvas.width = document.body.clientWidth;
canvas.height = document.body.clientHeight;
context.lineWidth = 3;
context.strokeStyle = 'red';
context.beginPath();
context.arc(200, 200, 100, (Math.PI / 180) * 0, (Math.PI / 180) * 360, false);
context.stroke();
context.closePath();
效果
使用clip()裁剪区域
*{margin:0; padding:0;}
html, body{width:100%; height:100%; overflow:hidden; background-color:#AFAFAF;}
var canvas = document.getElementById('canvas'),
context = canvas.getContext('2d');
canvas.width = document.body.clientWidth;
canvas.height = document.body.clientHeight;
context.lineWidth = 3;
context.strokeStyle = 'red';
context.rect(0, 0, 200, 200);
context.clip();
context.beginPath();
context.arc(200, 200, 100, (Math.PI / 180) * 0, (Math.PI / 180) * 360, false);
context.stroke();
context.closePath();
效果
也可以使用arc绘制圆形的剪裁区域
*{margin:0; padding:0;}
html, body{width:100%; height:100%; overflow:hidden; background-color:#AFAFAF;}
var canvas = document.getElementById('canvas'),
context = canvas.getContext('2d');
canvas.width = document.body.clientWidth;
canvas.height = document.body.clientHeight;
context.lineWidth = 3;
context.strokeStyle = 'red';
context.arc(100, 100, 150, (Math.PI / 180) * 0, (Math.PI / 180) * 360, false);
context.clip();
context.beginPath();
context.arc(200, 200, 100, (Math.PI / 180) * 0, (Math.PI / 180) * 360, false);
context.stroke();
context.closePath();
效果
使用save和restore实现只裁剪单个路径
*{margin:0; padding:0;}
html, body{width:100%; height:100%; overflow:hidden; background-color:#AFAFAF;}
var canvas = document.getElementById('canvas'),
context = canvas.getContext('2d');
canvas.width = document.body.clientWidth;
canvas.height = document.body.clientHeight;
context.lineWidth = 3;
context.strokeStyle = 'red';
context.save();
context.rect(0, 0, 200, 200);
context.clip();
context.beginPath();
context.arc(200, 200, 100, (Math.PI / 180) * 0, (Math.PI / 180) * 360, false);
context.stroke();
context.closePath();
context.restore();
context.beginPath();
context.arc(250, 250, 100, (Math.PI / 180) * 0, (Math.PI / 180) * 360, false);
context.stroke();
context.closePath();
效果
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脚本之家。
如果觉得《ipad html 自定义裁剪 canvas裁剪clip()函数的具体使用》对你有帮助，请点赞、收藏，并留下你的观点哦！
