resize.rb

require 'mini_magick' 
# for converting images from http://www.thecoverproject.net to printable pdfs.

# open 8.5x14 blank pdf
blank = MiniMagick::Image.open('blank_legal.jpg')

Dir.glob("input/*.jpg").each do |input_file|	
	
	p input_file

	# open jpg
	image = MiniMagick::Image.open(input_file)

	# rotate jpg 90 degrees
	image.rotate "90"

	# place jpg in center of pdf
	result = blank.composite(image) do |c|
		c.compose 'Over'
		c.gravity 'center'
	end

	# write pdf
	result.format 'pdf'
	result.write 'output' + input_file[5..-4] + 'pdf'
end