画布透明背景(css 马赛克背景)

canvas {
    
    
	background-color: #fff;
    background-image: linear-gradient(45deg,#ccc 25%,transparent 0),linear-gradient(45deg,transparent 75%,#ccc 0),linear-gradient(45deg,#ccc 25%,transparent 0),linear-gradient(45deg,transparent 75%,#ccc 0);
    background-position: 0 0,6px 6px,6px 6px,12px 12px;
    background-size: 12px 12px;
}