Module: ImageGenerator

Extended by:
ImageGenerator
Included in:
ImageGenerator
Defined in:
lib/captcha3/image_generator.rb

Constant Summary collapse

BITS = 
("A".."Z").to_a + (0..9).to_a
BIT_LENGTH = 
BITS.length
DEFAULT_PARAS = 
{
	:image_width => 150,
	:image_height => 50,
	:captcha_length => 5,
	:file_type => 'png'
}

Instance Method Summary collapse

Instance Method Details

#generate_captcha_image(params = {}) ⇒ Object 



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# File 'lib/captcha3/image_generator.rb', line 14

def generate_captcha_image(params = {})
	params.reverse_merge!(DEFAULT_PARAS)	
	file_type = %w(png gif).include?(params[:file_type]) ? ".#{params[:file_type]}" : ".png"

	text_img = Magick::Image.new(params[:image_width].to_i, params[:image_height].to_i)
	black_img = Magick::Image.new(params[:image_width].to_i, params[:image_height].to_i) do
		self.background_color = 'black'
	end

	random_string = params[:captcha_length].times.map{ BITS[rand(BIT_LENGTH)]}.join

	filename = CaptchaUtil.encrypt_string(random_string.downcase) + file_type

	# Render the text in the image
	text_img.annotate(Magick::Draw.new, 0,0,0,0, random_string) {
		self.gravity = Magick::WestGravity
		self.font_family = 'Courier-New'
		self.font_weight = Magick::BoldWeight
   	self.fill = '#000000'
  	self.stroke = 'black'
		self.stroke_width = 1
  	self.pointsize = 44
	}

  # Apply a little blur and fuzzing
	text_img = text_img.gaussian_blur(1.2, 1.2)
  text_img = text_img.sketch(20, 30.0, 30.0)
	text_img = text_img.wave(3, 90)

  # Now we need to get the white out
	text_mask = text_img.negate
  text_mask.matte = false

	# Add cut-out our captcha from the black image with varying tranparency
	black_img.composite!(text_mask, Magick::CenterGravity, Magick::CopyOpacityCompositeOp)

	# Write the file to disk
  puts 'Writing image file ' + filename
	black_img.write(filename) # { self.depth = 8 }

  # Collect rmagick
	GC.start
end