class Paperclip::Thumbnail

Handles thumbnailing images that are uploaded.

Attributes

convert_options[RW]
current_geometry[RW]
format[RW]
source_file_options[RW]
target_geometry[RW]
whiny[RW]

Public Class Methods

new(file, options = {}) click to toggle source

Creates a Thumbnail object set to work on the file given. It will attempt to transform the image into one defined by target_geometry which is a “WxH”-style string. format will be inferred from the file unless specified. Thumbnail creation will raise no errors unless whiny is true (which it is, by default. If convert_options is set, the options will be appended to the convert command upon image conversion

Calls superclass method Paperclip::Processor.new
# File lib/dm-paperclip/thumbnail.rb, line 13
def initialize file, options = {}, attachment = nil
  super

  geometry             = options[:geometry]
  @file                = file
  @crop                = geometry[-1,1] == '#'
  @target_geometry     = Geometry.parse geometry
  @current_geometry    = Geometry.from_file @file
  @source_file_options = options[:source_file_options]
  @convert_options     = options[:convert_options]
  @whiny               = options[:whiny].nil? ? true : options[:whiny]
  @format              = options[:format]

  @source_file_options = @source_file_options.split(/\s+/) if @source_file_options.respond_to?(:split)
  @convert_options     = @convert_options.split(/\s+/)     if @convert_options.respond_to?(:split)

  @current_format      = File.extname(@file.path)
  @basename            = File.basename(@file.path, @current_format)

end

Public Instance Methods

convert_options?() click to toggle source

Returns true if the image is meant to make use of additional convert options.

# File lib/dm-paperclip/thumbnail.rb, line 40
def convert_options?
  !@convert_options.nil? && !@convert_options.empty?
end
crop?() click to toggle source

Returns true if the target_geometry is meant to crop.

# File lib/dm-paperclip/thumbnail.rb, line 35
def crop?
  @crop
end
make() click to toggle source

Performs the conversion of the file into a thumbnail. Returns the Tempfile that contains the new image.

# File lib/dm-paperclip/thumbnail.rb, line 46
def make
  src = @file
  dst = Tempfile.new([@basename, @format ? ".#{@format}" : ''])
  dst.binmode

  begin
    parameters = []
    parameters << source_file_options
    parameters << ":source"
    parameters << transformation_command
    parameters << convert_options
    parameters << ":dest"

    parameters = parameters.flatten.compact.join(" ").strip.squeeze(" ")

    success = Paperclip.run("convert", parameters, :source => "#{File.expand_path(src.path)}[0]", :dest => File.expand_path(dst.path))
  rescue PaperclipCommandLineError => e
    raise PaperclipError, "There was an error processing the thumbnail for #{@basename}" if @whiny
  end

  dst
end
transformation_command() click to toggle source

Returns the command ImageMagick's convert needs to transform the image into the thumbnail.

# File lib/dm-paperclip/thumbnail.rb, line 71
def transformation_command
  scale, crop = @current_geometry.transformation_to(@target_geometry, crop?)
  trans = []
  trans << "-resize" << %Q["#{scale}"] unless scale.nil? || scale.empty?
  trans << "-crop" << %Q["#{crop}"] << "+repage" if crop
  trans
end