清除当前canvas(绘图环境context)的左半部分的内容,然后绘制canvas,下方需补全的代码是? // 此处为清除canvas的左半部分的内容 ----- 补全代码处 ----- offcanvas.getContext('2d').drawImage(canvas, 0,0);
A.
canvas.clearRect(0, 0, offcanvas.width/2, offcanvas.height);
B.
context . clearRect(canvas.width/2, canvas.height, 0, 0);
C.
context.clearRect(0, 0, offcanvas.width/2, offcanvas.height);
D.
canvas .getContext('2d') .clearRect(0, 0, canvas.width/2, canvas.height);