add readme

README.md

@@ -0,0 +1,70 @@
+<!--
+ * @Descripttion: 
+ * @Author: sunft
+ * @Date: 2020-05-22 13:54:30
+ * @LastEditTime: 2020-05-22 13:57:44
+--> 
+<h1 align="center">sprite-smith-loader</h1>
+
+
+![image](https://img.shields.io/badge/license-MIT-green) 
+![image](https://img.shields.io/badge/webpack-%5E4.0.0-blue)
+
+:rocket: [中文文档点这里](https://github.com/sunft1996/sprite-smith-loader/blob/master/README.CN.md/)
+## Introduce
+Sprite Smith loader is a tool for automatically generating CSS Sprites. You can use it in webpack. It will automatically generate CSS Sprites and modify the corresponding CSS code.
+## Getting Started
+To begin, you'll need to install sprite-smith-loader:
+
+```
+npm install --save-dev css-loader
+```
+Then add the plugin to your webpack config. For example:
+
+**webpack.config.js**
+
+```
+module.exports = {
+  module: {
+    rules: [
+      {
+        test: /\.css$/i,
+        use: ['style-loader', 'css-loader','sprite-smith-loader'],
+      },
+    ],
+  },
+};
+```
+
+## Usage
+Modify your CSS file
+```
+.my_bg_1{
+    height: 100px;
+    width: 100px;
+    background: url('./demo1_sprite.png') 0px 0px;
+    background-size: 100px 100px;
+}
+
+.my_bg_2{
+    height: 100px;
+    width: 100px;
+    background: url('./demo2_sprite.png') -20px -20px;
+    background-size: 150px 150px;
+}
+```
+After the CSS Sprites is generated, the loader will modify the background attribute in the CSS. In order to accurately calculate the converted background attribute, please follow the following specifications:
+
+Css attribute name | isRequired | Description
+---|---|---
+height | true| Unit: PX
+width | true| Unit: PX
+background-size | true| Unit: PX
+background | true| Include image，position，repeat
+background-image | true| Included in background，picture name with _ sprite.png ending
+background-position | false| Included in background，format of value PX PX
+background-repeat | false| Included in background，must be no-repeat
+
+## License
+
+[MIT](https://github.com/sunft1996/sprite-smith-loader/blob/master/LICENSE)