How do I configure a JPEG delegate for graphicsmagick?

问题

I want to crop an image to a specified pixel region. I'd like to use the gm module from https://github.com/aheckmann/gm. I am running Linux Mint 13 and node.js v0.9.4pre.

I am running into an error that sounds like graphicsmagick doesn't know about jpegs:

Error: Command failed: gm convert: No decode delegate for this image format (./assets/images/temp/2aadd4379e1cf2b59429994270db2a8a.jpg)

Sure enough, gm convert -list formats shows no jpeg delegate:

<snip>
     IPTC P  rw-  IPTC Newsphoto
 IPTCTEXT P  rw-  IPTC Newsphoto text format
IPTCWTEXT P  rw-  IPTC Newsphoto text format
      K25 S  r--  Kodak Photo RAW
<snip>

graphicsmagick has a ftp folder containing source code for delegates (with a readme.) So I downloaded, untarred, and installed jpegsrc.v6b.tar.gz as suggested in both the install document that came with my source files.

I'm pretty sure the jpeg library installed cjpeg and djpeg and perhaps other stuff. However there is no make uninstall or manifest that I found. I haven't tried installing any other versions of the jpeg library over this one. I uninstalled and rebuilt graphicsmagick after installing the jpeg library.

Still, there is no JPEG delegate listed in gm convert -list formats.

I am migrating from Imagemagick which never had any problems resizing jpegs, even without my installing this library.

What must I do to get graphicsmagic to handle jpegs?

Here's how I am invoking gm:

    var gmagic = require('gm');
    gmagic(cfg.tmpPath)
    .crop(h,w,x0,y0)
    .write(cfg.croppedPath, function(err){
      if(err){ done(err) } 
        else { done(null, cfg.croppedPath) };
    });

Here are the commands I used to install the jpeg library and graphicsmagick:

$ cd ~/source
$ wget http://www.ijg.org/files/jpegsrc.v6b.tar.gz
$ tar -xzvf jpegsrc.v6b.tar.gz
$ cd jpeg-6b
$ ./configure
$ make
$ sudo make install

$ cd ~/source
$ wget ftp://ftp.graphicsmagick.org/pub/GraphicsMagick/1.3/GraphicsMagick-1.3.18.tar.xz
$ tar -xJvf GraphicsMagick-1.3.18.tar.xz
$ cd GraphicsMagick-1.3.18
$ ./configure
$ make
$ sudo make install

$ npm install gm

回答1:

I found a successful workaround by telling the gm library to use imagemagick binaries instead of default graphicsmagic binaries:

var gmagic   = require('gm');
var imagic   = gmagic.subClass({imageMagick: true});
...
imagic(cfg.tmpPath)
.crop(h,w,x0,y0)
.write(cfg.croppedPath, function(err, stdout, stderr, command){
  if(err){ next(err) }
  else { next(null, raft) };
});

回答2:

Given that you are using Linux Mint, the best solution for GraphicsMagick to find libjpeg is to install the libjpeg development package (libjpeg-dev), re-run the GraphicsMagick configure script, rebuild, and install. Be sure to add -dev packages for libraries supporting other formats you are interested in.

If you want to use the libjpeg installed from source code, then you will need to add the options LDFLAGS=-L/usr/local/lib CPPFLAGS=-I/usr/local/include to the GraphicsMagick configure script invocation. Be aware that Linux Mint may come with a different libjpeg than jpeg 6b (e.g. jpeg 8 or libjpeg turbo) and it is best not to have duplicate libraries on the system.

回答3:

I realise this is strictly a Linux question, but maybe this will help someone...

On Mac, I used HomeBrew instead. Just run these 3 lines (the chown line was necessary for me, you might want to try without first):

ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)"
sudo chown -R $USER:admin /usr/local
brew install graphicsmagick

If it complains about jpeg libraries being unlinked, run brew doctor + follow instructions to link any missing "kegs".

And if something gets messed up and you want to start over (see https://stackoverflow.com/a/17846596/188926):

brew uninstall imagemagick graphicsmagick libpng jpeg
brew cleanup -s
brew install graphicsmagick

来源：https://stackoverflow.com/questions/16094875/how-do-i-configure-a-jpeg-delegate-for-graphicsmagick

标签

node.js

ImageMagick

jpeg

graphicsmagick