Installing RMagick on Cygwin

RMagick is a Ruby to ImageMagick framework that’s needed if you want to edit images using Rails. FileColumn, a Rails plugin for handling file uploads, plugs into RMagick very smoothly. While FileColumn is really simple to use, installing RMagick on Cygwin seemed really daunting. There were a bunch of warnings on how it differs from a usual Rails plugin install. So I’m summarizing my experience here:

1. First install ImageMagick for Cygwin. Do this by updating Cygwin itself, using the Cygwin setup program. It’s the same approach as you use for installing Cygwin the first time around. When you get to the Select Packages page, find the ImageMagick packages under the Graphics node and make sure they’re set to be installed. Look for libImageMagick1; there are a few others.
2. Run gem update –system
3. Download the RMagick gem for Linux. Not the Win32 one. That’s the one called “rmagick”. You have to download it; you can’t install it remotely.
4. From the directory where you downloaded the RMagick gem, run gem install rmagick –local
5. Rebase Cygwin. I’ve never had to do this before, but I got a bunch of errors in the Ruby server output console saying the following when RMagick was used:
   unable to remap C:\cygwin\usr\X11R6\bin\cygXext-6.dll to same address ruby died waiting for dll loading, errno 11
   To rebase Cygwin, close all your Cygwin shells, and open an ash shell by going to Start>Run…, then enter C:\cygwin\bin\ash.exe in the Run dialog and click OK. Run /bin/rebaseall from the ash console.

Then restart the Rails server from script.

For reference, I used RMagick 2.5.2, with Ruby 1.8.2 and Rails 2.1.0.