添加水印方法

export function watermark(settings) {

//默认设置

let defaultSettings={

watermark_txt:"text",

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:'#aaa',//水印字体颜色

watermark_alpha:0.4,//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:210,//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=p_width-cutWidth;

//获取页面最大高度

let page_height = Math.max(document.body.scrollHeight,document.body.clientHeight)+450;

// 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 || (parseInt(defaultSettings.watermark_x + defaultSettings.watermark_width *defaultSettings.watermark_cols + defaultSettings.watermark_x_space * (defaultSettings.watermark_cols - 1)) > page_width)) {

defaultSettings.watermark_cols = parseInt((page_width-defaultSettings.watermark_x+defaultSettings.watermark_x_space) / (defaultSettings.watermark_width + defaultSettings.watermark_x_space));

defaultSettings.watermark_x_space = parseInt((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 || (parseInt(defaultSettings.watermark_y + defaultSettings.watermark_height * defaultSettings.watermark_rows + defaultSettings.watermark_y_space * (defaultSettings.watermark_rows - 1)) > page_height)) {

defaultSettings.watermark_rows = parseInt((defaultSettings.watermark_y_space + page_height - defaultSettings.watermark_y) / (defaultSettings.watermark_height + defaultSettings.watermark_y_space));

defaultSettings.watermark_y_space = parseInt(((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.MozTransform = "rotate(-" + defaultSettings.watermark_angle + "deg)";

mask_div.style.msTransform = "rotate(-" + defaultSettings.watermark_angle + "deg)";

mask_div.style.OTransform = "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 = "9999";

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);

};

};

document.body.appendChild(oTemp);

}

使用方法

import { watermark } from './../common/watermark';

watermark({watermark_txt: '你要添加的水印'});

效果演示

源码地址

https://github.com/artdong/antd-admin

经典前端面试题每日更新，欢迎参与讨论，地址：https://github.com/daily-interview/fe-interview。

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