gm:如果图像大于1000px,则调整图像大小

Question

我试图通过gmin 进行一些图像处理collectionFS,因为我需要读取一个流并将其写回同一个文件,我必须使用一个临时文件 - 如下所示.

我想检查图像是否宽于1000px.在这种情况下,它应该重新调整为1000px.

不幸的是,这不起作用,因为我得到了错误TypeError: Object [object Object] has no method 'pipe'和Error: gm().stream() or gm().write() with a non-readable stream.

var fs       = Npm.require('fs'),
    file     = Images.findOne({ _id: fileId }),
    read     = file.createReadStream('public'),
    filename = '/tmp/gm_' + Date.now(),
    temp     = fs.createWriteStream(filename);

if (method == 'resize') {
    // resize to 1000px, if image is bigger
    gmread = gm(read);
    gmread.size(function(err, size){
        if(size.width > 1000) {
            gmread.resize('1000').stream();
        }
    });
}

gmread.on('end', Meteor.bindEnvironment(function (error, result) {
    if (error) console.warn(error);

    var tmpread = fs.createReadStream(filename);
        write   = file.createWriteStream('public');

    tmpread.on('end', Meteor.bindEnvironment(function (error, result) { 
        if (error) console.warn(error);
    }));

    tmpread.pipe(write);
}));

gmread.pipe(temp);

Answer 1

我认为collectionFS中正确的方法是这样的：

var gmread = gm(readStream, fileObj.name());
gmread.size({bufferStream: true}, FS.Utility.safeCallback(function (error, size) {
    if (error) console.warn(error);
    else {
        if(size.width > 1000) gmread.resize('1000').stream().pipe(writeStream);
    }
}));

也许您想将其放入transformWrite您商店的功能中......