Generate iOS launch screen images

launchscreen.rb

#!/usr/bin/env ruby

require 'rmagick'

if ARGV.length < 2
	puts "Usage: #{$PROGRAM_NAME} <logo path> <background color>"
	exit
end

logopath = ARGV[0]
background_color = ARGV[1]
logo = Magick::Image::read(logopath).first

{
	"iphone4" => [640, 960],
	"iphone5" => [640, 1136],
	"iphone6" => [750, 1334],
	"iphone6plus" => [1242, 2208],
}.each {|key, size|
	Magick::Image.new(size[0], size[1]) {
		self.background_color = background_color
	}
	.composite!(logo, Magick::CenterGravity, Magick::OverCompositeOp)
	.write "#{key}@2x.png"
}