新增demo

demo/loaders/sprite-smith-loader.js

@@ -0,0 +1,183 @@
+const fs = require('fs');
+const path = require('path');
+const Spritesmith = require('spritesmith');
+const { stringifyRequest } = require('loader-utils');
+var valueParser = require('postcss-value-parser');
+
+module.exports = function (source) {
+
+    let outputName = new Date().getTime() + '_smith.png';
+    // 清除css中的注释
+    const cleanSource = source.replace(/\/\*[\w\W]*\*\//g, '')
+
+    let imgs = cleanSource.match(/url\(.+_sprite.+\)/g);
+
+    const callback = this.async();
+
+    imgs = imgs.map(item => path.resolve(this.context, item.replace(/(url\(.)|(.\))/g, '')));
+
+    Spritesmith.run({ src: imgs }, async (err, result) => {
+        if (err) throw err;
+
+        // 雪碧图尺寸
+        const imgInfo = result.properties;
+
+        // 子图片的偏移、尺寸信息
+        const coord = {};
+
+        for (key in result.coordinates) {
+            let newKey = key.match(/\w+_sprite.+/)[0];
+            coord[newKey] = result.coordinates[key];
+            delete result.coordinates[key];
+        }
+
+        const emitFile = (name) => {
+            return new Promise((resolve) => {
+                fs.mkdir(this.context + '/sprites', { recursive: true }, (err) => {
+                    if (err) {
+                        throw (err);
+                    }
+                    fs.writeFileSync(path.resolve(this.context, 'sprites', name), result.image);
+                    resolve();
+                });
+            });
+        }
+        // 当前目录生成雪碧图
+        await emitFile(outputName);
+
+        let parsedValue = valueParser(cleanSource);
+
+        // 包含所有需要转化的css块
+        let blocks = {};
+
+        // 找到当前css块的范围
+        function findCurrentDeclare(currentIndex) {
+            let beginIndex;
+
+            let endIndex;
+
+            parsedValue.walk(node => {
+                if (/\{/.test(node.value) && node.sourceIndex < currentIndex) {
+                    beginIndex = node.sourceIndex;
+                }
+                if (endIndex === undefined && /\}/.test(node.value) && node.sourceIndex > currentIndex) {
+                    endIndex = node.sourceIndex;
+                }
+            });
+            if (beginIndex === undefined || endIndex === undefined) throw new Error(`css code error!`);
+            return {
+                beginIndex,
+                endIndex,
+                currentIndex
+            };
+        }
+
+        parsedValue.walk(node => {
+            if (node.value === 'url' && /_sprite.+/.test(node.nodes[0].value)) {
+                blocks[node.sourceIndex] = findCurrentDeclare(node.sourceIndex);
+                blocks[node.sourceIndex].url = node.nodes[0].value.match(/\w+_sprite.+/)[0];
+            }
+        });
+
+        // 转换
+        for (const key in blocks) {
+            let bgLineStart = 0;
+            let bgLineEnd = 0;
+            let bgszLineStart = 0;
+            let bgszLineEnd = 0;
+            let width;
+            let height;
+            let x;
+            let y;
+            let ratio;
+            const item = blocks[key];
+            // 找到background所在行
+            parsedValue.walk(node => {
+                if (blocks[key].beginIndex <= node.sourceIndex && blocks[key].endIndex >= node.sourceIndex) {
+                    if (bgLineStart !== 0 && bgLineEnd !== 0) return;
+
+                    if (bgLineStart === 0 && node.value === 'background') {
+                        bgLineStart = node.sourceIndex;
+                        return;
+                    }
+
+                    if (bgLineStart !== 0 && /;/.test(node.value)) {
+                        bgLineEnd = node.sourceIndex;
+                        return;
+                    }
+
+                }
+            });
+            // 找到background-size所在行
+            parsedValue.walk(node => {
+                if (blocks[key].beginIndex <= node.sourceIndex && blocks[key].endIndex >= node.sourceIndex) {
+                    if (bgszLineStart !== 0 && bgszLineEnd !== 0) return;
+
+                    if (bgszLineStart === 0 && node.value === 'background-size') {
+                        bgszLineStart = node.sourceIndex;
+                        return;
+                    }
+
+                    if (bgszLineStart !== 0 && /;/.test(node.value)) {
+                        bgszLineEnd = node.sourceIndex;
+                        return;
+                    }
+
+                }
+            });
+
+            // 处理 background-size
+            parsedValue.walk(node => {
+                if (bgszLineStart <= node.sourceIndex && bgszLineEnd >= node.sourceIndex) {
+
+                    // 若background-size只有一个px
+                    if (width === undefined && /px;/.test(node.value)) {
+                        ratio = node.value.match(/\d+/)[0] / coord[item.url].width;
+                        width = imgInfo.width * ratio + 'px ';
+                        height = imgInfo.height * ratio + 'px;';
+                        node.value = width + height;
+                        return;
+                    }
+                    if (width === undefined && /px/.test(node.value)) {
+                        ratio = node.value.match(/\d+/)[0] / coord[item.url].width;
+                        width = imgInfo.width * ratio + 'px';
+                        node.value = width;
+                        return;
+                    }
+                    if (width !== undefined && height === undefined && /px;/.test(node.value)) {
+                        height = imgInfo.height * ratio + 'px;';
+                        node.value = height;
+                        return;
+                    }
+
+
+                }
+            });
+            // 处理 background
+            if (ratio) {
+                parsedValue.walk(node => {
+                    if (bgLineStart <= node.sourceIndex && bgLineEnd >= node.sourceIndex) {
+
+                        if (x === undefined && /px/.test(node.value)) {
+                            x = - coord[item.url].x * ratio + Number(node.value.match(/-?\d+/)[0]) + 'px';
+                            node.value = x;
+                            return;
+                        }
+                        if (x !== undefined && y === undefined && /px;/.test(node.value)) {
+                            y = - coord[item.url].y * ratio + Number(node.value.match(/-?\d+/)[0]) + 'px;';
+                            node.value = y;
+                            return;
+                        }
+                        if (x !== undefined && y === undefined && /px/.test(node.value)) {
+                            y = - coord[item.url].y * ratio + Number(node.value.match(/-?\d+/)[0]) + 'px';
+                            node.value = y;
+                            return;
+                        }
+                    }
+                });
+            }
+        }
+        callback(null, parsedValue.toString().replace(/url\(.+_sprite.+\)/g, `url(${stringifyRequest(this.context, './sprites/' + outputName)})`));
+    });
+
+}

demo/resource/index.html

@@ -0,0 +1,20 @@
+<!--
+ * @Descripttion: 
+ * @Author: sunft
+ * @Date: 2020-05-14 10:52:55
+ * @LastEditTime: 2020-05-22 14:13:22
+ -->
+<!DOCTYPE html>
+<html lang="en">
+
+<head>
+    <meta charset="UTF-8">
+    <meta name="viewport" content="width=device-width, initial-scale=1.0">
+    <title>demo</title>
+</head>
+
+<body>
+    <div id='root'></div>
+</body>
+
+</html>

demo/resource/index.js

@@ -0,0 +1,15 @@
+/*
+ * @Descripttion: 
+ * @Author: sunft
+ * @Date: 2020-05-14 13:18:03
+ * @LastEditTime: 2020-05-22 11:35:52
+ */
+require('./style.css');
+
+document.getElementById('root').innerHTML =
+`<h3 class="text_center">this is a demo</h3>
+<div class="my_content">
+    <div class="my_bg_1"></div>
+    <div class="my_bg_2"></div>
+</div>`
+

demo/resource/style.css

@@ -0,0 +1,27 @@
+.my_bg_1{
+    height: 100px;
+    width: 100px;
+    background: url('./demo1_sprite.png');
+    background-size: 100px;
+    border: 1px solid #ddd;
+    display: inline-block;
+}
+
+.my_bg_2{
+    height: 100px;
+    width: 100px;
+    background: url('./demo2_sprite.png') no-repeat -20px -20px;
+    background-size: 150px;
+    border: 1px solid #ddd;
+    display: inline-block;
+    margin-left: 20px;
+}
+
+.my_content{
+    display: flex;
+    justify-content: center;
+}
+
+.text_center{
+    text-align: center;
+}

demo/webpack.config.js

@@ -0,0 +1,54 @@
+/*
+ * @Descripttion: 
+ * @Author: sunft
+ * @Date: 2020-03-24 11:19:44
+ * @LastEditTime: 2020-05-22 14:58:48
+ */
+const path = require("path");
+const webpack = require("webpack");
+const HtmlWebpackPlugin = require('html-webpack-plugin'); 
+module.exports = {
+    entry: {
+        index: './resource/index.js',
+    },     
+    output: {
+        filename: '[name].bundle.js', 
+        path: path.resolve(__dirname, 'dist')  
+    },    
+    module: {
+        rules: [
+            {
+                test: /\.(png|jpe?g|gif)$/i,
+                loader: 'file-loader',
+                options: {
+                    outputPath: 'images',
+                },
+            },
+            {
+                test: /\.css$/i,
+                use: [
+                    'style-loader',
+                    'css-loader',
+                    'sprite-smith-loader'
+                ],
+            },
+        ],
+    },   
+    resolveLoader: {
+        // tell webpack where to find modules
+        modules: ['node_modules', path.join(__dirname, './loaders')],
+    },
+    plugins: [
+        new webpack.HotModuleReplacementPlugin(),  
+        new HtmlWebpackPlugin({
+            template: './resource/index.html',  
+        }),
+    ],
+    devServer: {
+        hot: true,                
+        contentBase: './dist',     
+        port: 4000,                
+        https: false,              
+        open: true                 
+    },
+}

dist/index.js

@@ -125,7 +125,6 @@ module.exports = function (source) {
 
                 }
             });
-            console.log(bgszLineStart, bgszLineEnd, bgLineStart, bgLineEnd)
 
             // 处理 background-size
             parsedValue.walk(node => {