Understanding ImageMagick's convert and translating to Ruby RMagick

Question

I\'m failing at translating the following PHP/ImageMagick code into Ruby RMagick (to make it more manageable for future users and to understand what it\'s really doing):

Answer 1

why did you not copy just the command and call it with system ?

no gems required ... no questions, code should look almost the same.

EDIT: RMagic only wraps imagemagic so why to bother with rmagic if you already have imagmagic command string.