在canvas中,可以使用clip()函數裁切區域,設定裁切區域後,只有在區域內的影像才能顯示,其餘部分會被屏蔽掉。本文主要和大家介紹了canvas裁剪clip()函數的具體使用的相關資料,希望能幫助大家。
未使用裁切繪製一個圓形
<!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
##
<!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
使用clip()裁切區域
<!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
也可以使用arc繪製圓形的剪裁區域
<!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.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
##使用save和restore實現只裁切單一路徑
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