亚洲国产日韩欧美一区二区三区,精品亚洲国产成人av在线,国产99视频精品免视看7,99国产精品久久久久久久成人热,欧美日韩亚洲国产综合乱

キャンバスの透明な長方形

長方形領(lǐng)域をクリア context.clearRect(x,y,width,height)

長方形領(lǐng)域をクリア context.clearRect (x, y, width, height)

を使用
學(xué)び続ける
||
<!DOCTYPE html> <html> <head> <meta charset="UTF-8"> <title>huatu</title> <style> body{ background: #dddddd; } #canvas{ margin: 10px; background: #ffffff; border: thin inset #aaaaaa; } </style> </head> <body> <canvas id="canvas" width="600" height="400"> Canvas not Supported </canvas> <script> var canvas=document.getElementById('canvas'), context=canvas.getContext('2d'); context.lineJoin='round'; context.lineWidth=30; context.font='24px Helvetica'; context.fillText('Click anywhere to erase',175,40); context.strokeRect(75,100,200,200); context.fillRect(325,100,200,200); context.canvas.onmousedown = function(e) { context.clearRect(0,0,600,400); } </script> </body> </html>