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<!DOCTYPE html> <html lang=en> <head> <meta charset=UTF-8> <title></title> <style> *{margin:0; padding:0;} html, body{width:100%; height:100%; overflow:hidden; background-color:#AFAFAF;} </style> </head> <body> <canvas id=canvas></canvas> <script> 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(); </script> </body> </html> 效果
使用clip()裁剪区域<!DOCTYPE html> <html lang=en> <head> <meta charset=UTF-8> <title></title> <style> *{margin:0; padding:0;} html, body{width:100%; height:100%; overflow:hidden; background-color:#AFAFAF;} </style> </head> <body> <canvas id=canvas></canvas> <script> 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(); </script> </body> </html> 效果
也可以使用arc绘制圆形的剪裁区域<!DOCTYPE html> <html lang=en> <head> <meta charset=UTF-8> <title></title> <style> *{margin:0; padding:0;} html, body{width:100%; height:100%; overflow:hidden; background-color:#AFAFAF;} </style> </head> <body> <canvas id=canvas></canvas> <script> 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(); </script> </body> </html> 效果
使用save和restore实现只裁剪单个路径<!DOCTYPE html> <html lang=en> <head> <meta charset=UTF-8> <title></title> <style> *{margin:0; padding:0;} html, body{width:100%; height:100%; overflow:hidden; background-color:#AFAFAF;} </style> </head> <body> <canvas id=canvas></canvas> <script> 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(); </script> </body> </html> 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VeVb武林网。