node.js中使用imagemagick進行圖片裁剪壓縮

node.js中使用imagemagick進行圖片裁剪壓縮

1. 安裝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. 安裝GraphicsMagick for node http://aheckmann.github.com/gm/

   npm install gm

3. node.js代碼

   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'));

   處理網上圖片：

   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'));

錯誤處理

1. 如出現如下錯誤，請參考：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. 若是configure提示「configure: error: libltdl is required for modules build」，則yum search ltdl，而後（以CentOS 6.3 64bit 爲例）

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