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