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

   1 require 'image_science'
   2 module Technoweenie # :nodoc:
   3   module AttachmentFu # :nodoc:
   4     module Processors
   5       module ImageScienceProcessor
   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 Image Science image for the given binary data.
  13           def with_image(file, &block)
  14             ::ImageScience.with_image file, &block
  15           end
  16         end
  17
  18         protected
  19           def process_attachment_with_processing
  20             return unless process_attachment_without_processing && image?
  21             with_image do |img|
  22               self.width  = img.width  if respond_to?(:width)
  23               self.height = img.height if respond_to?(:height)
  24               resize_image_or_thumbnail! img
  25             end
  26           end
  27
  28           # Performs the actual resizing operation for a thumbnail
  29           def resize_image(img, size)
  30             # create a dummy temp file to write to
  31             # ImageScience doesn't handle all gifs properly, so it converts them to
  32             # pngs for thumbnails.  It has something to do with trying to save gifs
  33             # with a larger palette than 256 colors, which is all the gif format
  34             # supports.
  35             filename.sub! /gif$/, 'png'
  36             content_type.sub!(/gif$/, 'png')
  37             temp_paths.unshift write_to_temp_file(filename)
  38             grab_dimensions = lambda do |img|
  39               self.width  = img.width  if respond_to?(:width)
  40               self.height = img.height if respond_to?(:height)
  41               img.save self.temp_path
  42               self.size = File.size(self.temp_path)
  43               callback_with_args :after_resize, img
  44             end
  45
  46             size = size.first if size.is_a?(Array) && size.length == 1
  47             if size.is_a?(Fixnum) || (size.is_a?(Array) && size.first.is_a?(Fixnum))
  48               if size.is_a?(Fixnum)
  49                 img.thumbnail(size, &grab_dimensions)
  50               else
  51                 img.resize(size[0], size[1], &grab_dimensions)
  52               end
  53             else
  54               new_size = [img.width, img.height] / size.to_s
  55               img.resize(new_size[0], new_size[1], &grab_dimensions)
  56             end
  57           end
  58       end
  59     end
  60   end
  61 end