A demo snippet for adding some text to an image using ImageMagick

labelize.rb

#!/usr/bin/env ruby

# convert \
#   -font '/Library/Fonts/Comic Sans MS Bold.ttf' \
#   -pointsize 48 demo.png \
#   -fill yellow -annotate +50+100 'Merry Christmas' \
#   -fill white -annotate +50+170 'Helen' \
#   wtf.png

require 'mini_magick'

font_family = '/Library/Fonts/Tahoma.ttf'
font_family_bold = '/Library/Fonts/Tahoma Bold.ttf'
font_size = 48
padding = 40

color = '#ffffff'

title = 'The quick brown fox jumps over the lazy dog'
receiver_name = 'Helen'

MiniMagick::Tool::Convert.new do |convert|
  convert.merge! ['-font', font_family]
  convert.merge! ['-pointsize', font_size]
  convert.background 'none'
  convert.fill color
  convert << "label:for"
  convert << 'for.png'
end

MiniMagick::Tool::Convert.new do |convert|
  convert.merge! ['-font', font_family_bold]
  convert.merge! ['-pointsize', font_size]
  convert.background 'none'
  convert.fill(color)
  convert << "label:#{receiver_name.upcase}"
  convert << "receiver.png"
end

MiniMagick::Tool::Convert.new do |convert|
  convert << 'for.png'
  convert << 'receiver.png'
  convert.background 'none'
  convert.append
  convert << 'text.png'
end

MiniMagick::Tool::Convert.new do |convert|
  convert << 'text.png'
  convert << '('
  convert << '+clone'
  convert.background('#000000').shadow('20x2+2+2')
  convert << ')'
  convert.swap.+
  convert.background 'none'
  convert.flatten
  convert << 'text_shadow.png'
end

MiniMagick::Tool::Composite.new do |composite|
  composite << 'text_shadow.png'
  composite.geometry("+#{padding}+#{padding}") << 'theme.png' << 'ecard.png'
end

MiniMagick::Tool::Mogrify.new do |mogrify|
  mogrify.resize(720) << 'ecard.png'
end

MiniMagick::Tool::Composite.new do |composite|
  composite.geometry("+0-98")
  composite.gravity('center')
  composite << 'ecard.png' << 'envelope-back.png' << 'ecard_on_envelope.png'
end

MiniMagick::Tool::Composite.new do |composite|
  composite.geometry("+0+35")
  composite.gravity('center')
  composite << 'envelope-front.png' << 'ecard_on_envelope.png' << 'ecard_in_envelope.png'
end