如何在Heroku上使用ImageMagick操纵PNG图像

Question

I'm using rmagick gem, and I had to install the PNG library from here locally.

$ convert --version
Version: ImageMagick 6.8.9-1 Q16 x86_64 2014-05-12 http://www.imagemagick.org
Copyright: Copyright (C) 1999-2014 ImageMagick Studio LLC
Features: DPC Modules
Delegates: bzlib freetype jng jpeg ltdl lzma png xml zlib

But on Heroku, I don't have this delegate:

~ $ convert --version
Version: ImageMagick 6.7.7-10 2014-03-06 Q16 http://www.imagemagick.org
Copyright: Copyright (C) 1999-2012 ImageMagick Studio LLC
Features: OpenMP    

And it's impossible to install it, because Heroku don't let me use sudo .

Any ideas on how to solve this?

Update 17/11:

I already using the rmagick gem in my app. But, I have to manipulate PNG images and ImageMagick requires the png delegate to do this.

My problem isn't the gem. But the png delegate.

Answer 1

You can use a Heroku buildpack to install the dependencies.

There's an ImageMagick buildpack available here . Just follow the instructions will do. Feel free to search "ImageMagick buildpack" on the web if you're not using Cedar14 stack.

Update on Nov 17:

Interesting, seems like Heroku already has ImageMagick installed(which explains why I don't have this problem when I use Paperclip gem) and it's pretty easy to require Rmagick class as show in this SO question . Explained in here too .

gem "rmagick", :require => 'RMagick'