index.js

var images = require('images'),
    path = require('path'),
    config = require('./config'),
    fs = require('fs'),
    pointerW = 0,
    Imagemin = require('imagemin'),
    imagemin = new Imagemin();

var imageList = []; // 从给定目录中得到的图片列表
var sortFunc = config.sortFunc || null;

function init(config) {
    config.dest && fs.exists(config.dest, function (exists) {
        if (!exists) {
            fs.mkdirSync(config.dest);
        }
    });
    getImageListFormDir(config.imgSrc);
}

init(config);

function getImageListFormDir(path) {
    fs.exists(path, function(e) {
        if (e) {
            fs.readdir(path, function(err, files) {
                if (err) {
                    console.log('[ERROR] ', '读取文件错误！');
                } else {
                    if (files.length) {
                        files = files.sort(sortFunc); // 根据文件名做一个简单的排序
                        if (path[path.length - 1] !== '/')
                            path = path + '/';
                        files.forEach(function(file, index) {
                            var img = images(path + file);
                            imageList.push({
                                filename: path + file,
                                width: img.width(),
                                height: img.height()
                            });
                        });

                        //images.gc();
                        // 利用上面的参数进行合并
                        imageSprite(imageList);
                    }
                }
            })
        } else {
            console.log('[ERROR] ', path, '不存在！');
        }
    })
}

function imageSprite(imageList) {
    var width, height,size = getImgAllWidth(imageList);
    if (config.isStrict) {
        width = (config.width + config.gap) * imageList.length;
        height = config.height;
    } else {
        width = size.width;
        height = size.height;
    }

    images.setLimit(width, height);
    var bg = images(width, height);
    if (!config.transparent)
        bg.fill(0xff, 0xff, 0xff, 1);

    var widthLabel = 0;
    imageList.forEach(function(image, index) {
        var img = images(image.filename);
        if (config.isStrict)
            img.size(config.width, config.height);
        bg.draw(img, widthLabel, 0);

        console.log('[INFO] 文件：', image.filename, '已拼合...');

        widthLabel += img.width() + config.gap;
    });

    // 保存图片
    config.outputName = config.outputName ? config.outputName : (Date.parse(new Date()) + '.png');
    var _o = path.join(config.dest, config.outputName);
    bg.save(_o, config.outputType);
    console.log('[INFO] 图片保存路径！', _o);
    console.log('[INFO] 开始压缩图片！');

    imagemin.src(_o).dest(_o).use(Imagemin.optipng({ optimizationLevel: 3 }));
    console.log('[INFO] 图片压缩完毕!');

    imagemin.optimize(function (err, file) {
        if (err) {
            throw err;
        }

        // console.log(file);
        // => { contents: <Buffer 89 50 4e ...>, mode: '0644' }
        // 自动生成配置文件
        //writeFile();
    });
}

function getImgAllWidth(imageList) {
    var width = 0, height = 0;
    imageList.forEach(function(image) {
        width += image.width;
        height = image.height > height ? image.height : height;
    });
    return {
        width: width,
        height: height
    };
}

function writeFile() {
    fs.open('conf.css', 'w', 0644, function(e, fd) {
        if (e) throw e;
        fs.writeSync(fd, cssConf);
    });

    fs.open('conf.js', 'w', 0644, function(e, fd) {
        if (e) throw e;
        fs.writeSync(fd, JSON.stringify(jsConf));
    });
}