mbchowdari
Joined: 08 May 2008
Posts: 52
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 Posted: Wed Jul 01, 2009 12:37 pm Post subject: Generating Barcode |
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Generating barcode:
In Your application you have to place the barcode_generator.rb at app/helpers
Note: this will not work without rmagick (Ruby ImageMagick interface) and gbarcode (GNU barcode)
barcode_generator.rb
class BarcodeGenerator
# Uses subprocesses because
# 1. ImageMagick/RMagick leaks memory,
# and doesn't work in a long-running process. The fork makes it safe.
# 2. The output from the Gbarcode and ImageMagick is often longer than the pipe buffer,
# so we have to empty the buffer from another subprocess
def BarcodeGenerator.get_barcode_image(barcode_string)
return BarcodeGenerator.get_subprocess_output do
barcode_generator = BarcodeGenerator.new
$stdout.write(barcode_generator.get_barcode_image(barcode_string))
end
end
def initialize
# we do the imports here to protect long-running processes (like mongrel) from ImageMagick's memory leaks
require 'RMagick'
require 'gbarcode'
end
def get_barcode_image(string_to_encode)
if string_to_encode.nil?
string_to_encode = "No string specified"
end
string_to_encode = remove_rails_file_extension(string_to_encode)
eps_barcode = get_barcode_eps(string_to_encode)
gif_barcode = convert_eps_to_gif(eps_barcode)
return gif_barcode
end
def remove_rails_file_extension(string_to_encode)
if string_to_encode[-4..-1] == ".png"
string_to_encode = string_to_encode[0..-5]
end
return string_to_encode
end
def get_barcode_eps(string_to_encode)
barcode_object = Gbarcode.barcode_create(string_to_encode)
Gbarcode.barcode_encode(barcode_object, Gbarcode::BARCODE_128)
return BarcodeGenerator.get_subprocess_output do
Gbarcode.barcode_print(barcode_object, $stdout, Gbarcode::BARCODE_OUT_EPS)
end
end
def convert_eps_to_gif(eps_image)
base64_eps_image = Base64.encode64(eps_image)
im = Magick::Image::read_inline(base64_eps_image).first
im.format = "GIF"
return BarcodeGenerator.get_subprocess_output do
im.write($stdout)
end
end
# execute a block's code in a subprocess, returning any output
def BarcodeGenerator.get_subprocess_output()
data = ""
IO.popen('-', 'r+') do |child_filehandle|
if child_filehandle
begin
data = child_filehandle.read
ensure
child_filehandle.close_write
end
else
yield
end
end
return data
end
end
In your controller,
string_to_encode = block_img || "ruby"
@barcode_image = BarcodeGenerator.get_barcode_image(string_to_encode)
@filename = "#{string_to_encode}.gif"
File.open("<image path>", "w") { |f| f.write(@barcode_image)}
Thank you,
Chowdari |
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