【项目问题】如何给网页设置背景水印

设置水印

函数定义

  watermark(settings?) {
    
    
    //默认设置
    let defaultSettings = {
    
    
      dom:document.body,
      watermark_txt: "信息技术有限公司",
      watermark_x: 20,//水印起始位置x轴坐标
      watermark_y: 20,//水印起始位置Y轴坐标
      watermark_rows: 20,//水印行数
      watermark_cols: 20,//水印列数
      watermark_x_space: 100,//水印x轴间隔
      watermark_y_space: 50,//水印y轴间隔
      watermark_color: '#000000',//水印字体颜色
      watermark_alpha: 0.06,//水印透明度
      watermark_fontsize: '15px',//水印字体大小
      watermark_font: '微软雅黑',//水印字体
      watermark_width: 350,//水印宽度
      watermark_height: 80,//水印长度
      watermark_angle: 15//水印倾斜度数
    };
    Object.assign(defaultSettings, settings);
    let oTemp = document.createDocumentFragment();
    //获取页面最大宽度
    let p_width = Math.max(document.body.scrollWidth, document.body.clientWidth);
    let cutWidth = p_width * 0.0150;
    let page_width = document.body.clientWidth*0.92;
    //获取页面最大高度
    let page_height = document.body.clientHeight*0.91;
    // let page_height = document.body.scrollHeight+document.body.scrollTop;
    //如果将水印列数设置为0，或水印列数设置过大，超过页面最大宽度，则重新计算水印列数和水印x轴间隔
    if (defaultSettings.watermark_cols === 0 || (defaultSettings.watermark_x + defaultSettings.watermark_width * defaultSettings.watermark_cols + defaultSettings.watermark_x_space * (defaultSettings.watermark_cols - 1)) > page_width) {
    
    
      defaultSettings.watermark_cols = (page_width - defaultSettings.watermark_x + defaultSettings.watermark_x_space) / (defaultSettings.watermark_width + defaultSettings.watermark_x_space);
      defaultSettings.watermark_x_space = (page_width - defaultSettings.watermark_x - defaultSettings.watermark_width * defaultSettings.watermark_cols) / (defaultSettings.watermark_cols - 1);
    }
    //如果将水印行数设置为0，或水印行数设置过大，超过页面最大长度，则重新计算水印行数和水印y轴间隔
    if (defaultSettings.watermark_rows === 0 || (defaultSettings.watermark_y + defaultSettings.watermark_height * defaultSettings.watermark_rows + defaultSettings.watermark_y_space * (defaultSettings.watermark_rows - 1)) > page_height) {
    
    
      defaultSettings.watermark_rows = (defaultSettings.watermark_y_space + page_height - defaultSettings.watermark_y) / (defaultSettings.watermark_height + defaultSettings.watermark_y_space);
      defaultSettings.watermark_y_space = ((page_height - defaultSettings.watermark_y) - defaultSettings.watermark_height * defaultSettings.watermark_rows) / (defaultSettings.watermark_rows - 1);
    }
    let x;
    let y;
    for (let i = 0; i < defaultSettings.watermark_rows; i++) {
    
    
      y = defaultSettings.watermark_y + (defaultSettings.watermark_y_space + defaultSettings.watermark_height) * i;
      for (let j = 0; j < defaultSettings.watermark_cols; j++) {
    
    
        x = defaultSettings.watermark_x + (defaultSettings.watermark_width + defaultSettings.watermark_x_space) * j;
        let mask_div = document.createElement('div');
        mask_div.id = 'mask_div' + i + j;
        mask_div.className = 'mask_div';
        mask_div.appendChild(document.createTextNode(defaultSettings.watermark_txt));
        //设置水印div倾斜显示
        mask_div.style.webkitTransform = "rotate(-" + defaultSettings.watermark_angle + "deg)";
        mask_div.style.transform = "rotate(-" + defaultSettings.watermark_angle + "deg)";
        mask_div.style.visibility = "";
        mask_div.style.position = "absolute";
        mask_div.style.left = x + 'px';
        mask_div.style.top = y + 'px';
        mask_div.style.overflow = "hidden";
        mask_div.style.zIndex = "9";
        mask_div.style.pointerEvents = 'none';//pointer-events:none 让水印不遮挡页面的点击事件
        mask_div.style.opacity = defaultSettings.watermark_alpha + "";
        mask_div.style.fontSize = defaultSettings.watermark_fontsize;
        mask_div.style.fontFamily = defaultSettings.watermark_font;
        mask_div.style.color = defaultSettings.watermark_color;
        mask_div.style.textAlign = "center";
        mask_div.style.width = defaultSettings.watermark_width + 'px';
        mask_div.style.height = defaultSettings.watermark_height + 'px';
        mask_div.style.display = "block";
        oTemp.appendChild(mask_div);
      };
    };
    defaultSettings.dom.appendChild(oTemp);
  }

函数实现

this.common.watermark(
{
    
    
	dom:document.getElementById("print-id"),
	watermark_txt:`“绝密信息，严禁外传”`}
);