全屏水印

		// 页面添加水印效果
	
		const setWatermark = (str: string) => {
	
		    const id = '1.23452384164.123412416';
	
		    if (document.getElementById(id) !== null) document.body.removeChild(<HTMLElement>document.getElementById(id));
	
		    const can = document.createElement('canvas');
	
		    can.width = 200;
	
		    can.height = 130;
	
		    const cans: any = can.getContext('2d');
	
		    cans.rotate((-20 * Math.PI) / 180);
	
		    cans.font = '12px Vedana';
	
		    cans.fillStyle = 'rgba(200, 200, 200, 0.30)';
	
		    cans.textBaseline = 'Middle';
	
		    cans.fillText(str, can.width / 10, can.height / 2);
	
		    const div = document.createElement('div');
	
		    div.id = id;
	
		    div.style.pointerEvents = 'none';
	
		    div.style.top = '15px';
	
		    div.style.left = '0px';
	
		    div.style.position = 'fixed';
	
		    div.style.zIndex = '10000000';
	
		    div.style.width = `${document.documentElement.clientWidth}px`;
	
		    div.style.height = `${document.documentElement.clientHeight}px`;
	
		    div.style.background = `url(${can.toDataURL('image/png')}) left top repeat`;
	
		    document.body.appendChild(div);
	
		    return id;
	
		};
	
		/**
	
		 * 页面添加水印效果
	
		 * @method set 设置水印
	
		 * @method del 删除水印
	
		 */
	
		const watermark = {
	
		    // 设置水印
	
		    set: (str: string) => {
	
		        let id = setWatermark(str);
	
		        if (document.getElementById(id) === null) id = setWatermark(str);
	
		    },
	
		    // 删除水印
	
		    del: () => {
	
		        let id = '1.23452384164.123412416';
	
		        if (document.getElementById(id) !== null) document.body.removeChild(<HTMLElement>document.getElementById(id));
	
		    },
	
		};
	
		// 导出方法
	
		export default watermark;