projects.mako.cc - selectricity/blob - vendor/plugins/attachment_fu/lib/technoweenie/attachment_fu/processors/mini_magick_processor.rb

   1 require 'mini_magick'
   2 module Technoweenie # :nodoc:
   3   module AttachmentFu # :nodoc:
   4     module Processors
   5       module MiniMagickProcessor
   6         def self.included(base)
   7           base.send :extend, ClassMethods
   8           base.alias_method_chain :process_attachment, :processing
   9         end
  10
  11         module ClassMethods
  12           # Yields a block containing an MiniMagick Image for the given binary data.
  13           def with_image(file, &block)
  14             begin
  15               binary_data = file.is_a?(MiniMagick::Image) ? file : MiniMagick::Image.from_file(file) unless !Object.const_defined?(:MiniMagick)
  16             rescue
  17               # Log the failure to load the image.
  18               logger.debug("Exception working with image: #{$!}")
  19               binary_data = nil
  20             end
  21             block.call binary_data if block && binary_data
  22           ensure
  23             !binary_data.nil?
  24           end
  25         end
  26
  27       protected
  28         def process_attachment_with_processing
  29           return unless process_attachment_without_processing
  30           with_image do |img|
  31             resize_image_or_thumbnail! img
  32             self.width = img[:width] if respond_to?(:width)
  33             self.height = img[:height] if respond_to?(:height)
  34             callback_with_args :after_resize, img
  35           end if image?
  36         end
  37
  38         # Performs the actual resizing operation for a thumbnail
  39         def resize_image(img, size)
  40           size = size.first if size.is_a?(Array) && size.length == 1
  41           img.combine_options do |commands|
  42             commands.strip unless attachment_options[:keep_profile]
  43
  44             # gif are not handled correct, this is a hack, but it seems to work.
  45             if img.output =~ / GIF /
  46               img.format("png")
  47             end
  48
  49             if size.is_a?(Fixnum) || (size.is_a?(Array) && size.first.is_a?(Fixnum))
  50               if size.is_a?(Fixnum)
  51                 size = [size, size]
  52                 commands.resize(size.join('x'))
  53               else
  54                 commands.resize(size.join('x') + '!')
  55               end
  56             # extend to thumbnail size
  57             elsif size.is_a?(String) and size =~ /e$/
  58               size = size.gsub(/e/, '')
  59               commands.resize(size.to_s + '>')
  60               commands.background('#ffffff')
  61               commands.gravity('center')
  62               commands.extent(size)
  63             # crop thumbnail, the smart way
  64             elsif size.is_a?(String) and size =~ /c$/
  65                size = size.gsub(/c/, '')
  66
  67               # calculate sizes and aspect ratio
  68               thumb_width, thumb_height = size.split("x")
  69               thumb_width   = thumb_width.to_f
  70               thumb_height  = thumb_height.to_f
  71
  72               thumb_aspect = thumb_width.to_f / thumb_height.to_f
  73               image_width, image_height = img[:width].to_f, img[:height].to_f
  74               image_aspect = image_width / image_height
  75
  76               # only crop if image is not smaller in both dimensions
  77               unless image_width < thumb_width and image_height < thumb_height
  78                 command = calculate_offset(image_width,image_height,image_aspect,thumb_width,thumb_height,thumb_aspect)
  79
  80                 # crop image
  81                 commands.extract(command)
  82               end
  83
  84               # don not resize if image is not as height or width then thumbnail
  85               if image_width < thumb_width or image_height < thumb_height
  86                   commands.background('#ffffff')
  87                   commands.gravity('center')
  88                   commands.extent(size)
  89               # resize image
  90               else
  91                 commands.resize("#{size.to_s}")
  92               end
  93             # crop end
  94             else
  95               commands.resize(size.to_s)
  96             end
  97           end
  98           temp_paths.unshift img
  99         end
 100
 101         def calculate_offset(image_width,image_height,image_aspect,thumb_width,thumb_height,thumb_aspect)
 102         # only crop if image is not smaller in both dimensions
 103
 104           # special cases, image smaller in one dimension then thumbsize
 105           if image_width < thumb_width
 106             offset = (image_height / 2) - (thumb_height / 2)
 107             command = "#{image_width}x#{thumb_height}+0+#{offset}"
 108           elsif image_height < thumb_height
 109             offset = (image_width / 2) - (thumb_width / 2)
 110             command = "#{thumb_width}x#{image_height}+#{offset}+0"
 111
 112           # normal thumbnail generation
 113           # calculate height and offset y, width is fixed
 114           elsif (image_aspect <= thumb_aspect or image_width < thumb_width) and image_height > thumb_height
 115             height = image_width / thumb_aspect
 116             offset = (image_height / 2) - (height / 2)
 117             command = "#{image_width}x#{height}+0+#{offset}"
 118           # calculate width and offset x, height is fixed
 119           else
 120             width = image_height * thumb_aspect
 121             offset = (image_width / 2) - (width / 2)
 122             command = "#{width}x#{image_height}+#{offset}+0"
 123           end
 124           # crop image
 125           command
 126         end
 127
 128
 129       end
 130     end
 131   end
 132 end