CentOS6 + RMagickでPDFをPNGに変換するための準備 ref: http://qiita.com/tady/items/fb6927f9b0031c36332b

file1.txt

sudo su - 

yum remove ImageMagick* ghostscript*

cd /usr/local/src

wget http://downloads.ghostscript.com/public/ghostscript-9.07.tar.gz
tar zxvf ghostscript-9.07.tar.gz
./configure
make
make install

wget ftp://ftp.imagemagick.org/pub/ImageMagick/ImageMagick.tar.gz
tar zxvf ImageMagick.tar.gz
./configure
make
make install

vim /etc/profile.d/rmagick.sh
export LD_LIBRARY_PATH=/usr/local/lib/

file2.txt

$ convert sample.pdf[0] sample.png

file4.txt

$ bundle install

file5.txt

LoadError: libMagickCore-6.Q16.so.2: cannot open shared object file: No such file or directory - /var/www/sample/shared/bundle/ruby/2.1.0/extensions/x86_64-linux/2.1.0-static/rmagick-2.13.3/RMagick2.so
/var/www/sample/shared/bundle/ruby/2.1.0/gems/activesupport-4.1.4/lib/active_support/dependencies.rb:247:in `require'
/var/www/sample/shared/bundle/ruby/2.1.0/gems/activesupport-4.1.4/lib/active_support/dependencies.rb:247:in `block in require'
/var/www/sample/shared/bundle/ruby/2.1.0/gems/activesupport-4.1.4/lib/active_support/dependencies.rb:232:in `load_dependency'
/var/www/sample/shared/bundle/ruby/2.1.0/gems/activesupport-4.1.4/lib/active_support/dependencies.rb:247:in `require'
/var/www/sample/shared/bundle/ruby/2.1.0/gems/rmagick-2.13.3/lib/RMagick.rb:11:in `<top (required)>'
/var/www/sample/releases/20140803054150/config/application.rb:7:in `<top (required)>'
/var/www/sample/releases/20140803054150/Rakefile:4:in `require'
/var/www/sample/releases/20140803054150/Rakefile:4:in `<top (required)>'
(See full trace by running task with --trace)

file6.txt

file = params[:file]
pdf = Magick::ImageList.new(file.path + '[0]') #=> 1ページ目のみ抽出
cover_tmp = Rails.root.join('public', file.original_filename)
pdf[0].write(cover_tmp)

Gemfile

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

Table1

$ convert sample-slide.pdf[0] sample-slide.png
   **** Warning:  File has an invalid xref entry:  70.  Rebuilding xref table.
Error: /limitcheck in --run--
Operand stack:
   --dict:6/15(L)--   C1   1   --dict:5/5(L)--   --dict:5/5(L)--   HWTTNI+HiraKakuPro-W6   --dict:11/12(ro)(G)--   --nostringval--   CIDFontObject   --dict:7/7(L)--   47182   --dict:7/7(L)--   --dict:5/13(L)--   --nostringval--   --nostringval--   508369   373655
Execution stack:
   %interp_exit   .runexec2   --nostringval--   --nostringval--   --nostringval--   2   %stopped_push   --nostringval--   --nostringval--   --nostringval--   false   1   %stopped_push   1862   1   3   %oparray_pop   1861   1   3   %oparray_pop   1845   1   3   %oparray_pop   --nostringval--   --nostringval--   2   1   1   --nostringval--   %for_pos_int_continue   --nostringval--   --nostringval--   false   1   %stopped_push   --nostringval--   --nostringval--   --nostringval--   %array_continue   --nostringval--   false   1   %stopped_push   --nostringval--   %loop_continue   --nostringval--   --nostringval--   --nostringval--   --nostringval--   --nostringval--   --nostringval--   %array_continue   --nostringval--   --nostringval--   --nostringval--   --nostringval--   --nostringval--   --nostringval--   %loop_continue   --nostringval--   --nostringval--   --nostringval--   %array_continue   --nostringval--   --nostringval--   --nostringval--
Dictionary stack:
   --dict:1157/1684(ro)(G)--   --dict:1/20(G)--   --dict:75/200(L)--   --dict:75/200(L)--   --dict:106/127(ro)(G)--   --dict:286/300(ro)(G)--   --dict:24/25(L)--   --dict:4/6(L)--   --dict:21/40(L)--   --dict:3/5(L)--   --dict:6/15(L)--   --dict:54/106(ro)(G)--   --dict:21/30(L)--
Current allocation mode is local
GPL Ghostscript 8.70: Unrecoverable error, exit code 1
convert: Postscript delegate failed `sample-slide.pdf': No such file or directory @ pdf.c/ReadPDFImage/611.
convert: missing an image filename `sample-slide.png' @ convert.c/ConvertImageCommand/2800.