node.js中使用imagemagick进行图片裁剪压缩

node.js中使用imagemagick进行图片裁剪压缩

1. 安装imagemagick

    sudo apt-get install imagemagick
   

   or

    wget http://www.imagemagick.org/download/ImageMagick.tar.gz
    tar zxvf ImageMagick.tar.gz
    cd ImageMagick
    ./configure --prefix=/usr/local
    make
    sudo make install
   

2. 安装GraphicsMagick for node http://aheckmann.github.com/gm/

    npm install gm
   

3. node.js代码

    var fs, gm;
    gm = require('gm');
   
    gm('./img/before.jpg').options({
      imageMagick: true
    }).resize(130, 105).write('./img/after.jpg', function(err) {
      if (err) {
        return console.error(err);
      }
      return console.log('success');
    });
   

   使用文件流：

    var fs, gm;
    gm = require('gm');
    fs = require('fs');
   
    gm(fs.createReadStream('./img/before.jpg')).options({
      imageMagick: true
    }).resize(130, 105).stream().pipe(fs.createWriteStream('./img/after.jpg'));
   

   处理网上图片：

    var fs, gm, request;
    gm = require('gm');
    fs = require('fs');
    request = require('request');
   
    gm(request('http://url_to_img.jpg')).options({
      imageMagick: true
    }).resize(130, 105).stream().pipe(fs.createWriteStream('./img/after.jpg'));
   

错误处理

1. 如出现以下错误，请参考：http://www.xgezhang.com/imagemagick_convert_problem.html

   convert: no decode delegate for this image format `JPEG' @ error/constitute.c/ReadImage/501.
   convert: no images defined `img/after.jpg' @ error/convert.c/ConvertImageCommand/3212.
   

2. 如果configure提示“configure: error: libltdl is required for modules build”，则yum search ltdl，然后（以CentOS 6.3 64bit 为例）

    yum install libtool-ltdl.x86_64
    yum install libtool-ltdl-devel.x86_64