Class: MountableImageServer::ImageProcessor

Inherits:
Object
  • Object
show all
Includes:
Skeptick
Defined in:
lib/mountable_image_server/image_processor.rb

Constant Summary collapse

VALID_PARAMETERS =

Accepted parameters and values: ‘fit` - Approach how to interpret width and height, use ’crop’ (cropping) or ‘clip’ (resizing) ‘w` - Width of image in pixels `h` - Height of image in pixels `q` - Quality of image, use value between 0 (worst) and 100 (best) `darken` - Blends image with black color, use value between 0 (no black) and 100 (completely black) `fm` - Format of image, use ’jpg’, ‘png’, ‘gif’, …

[:fit, :w, :h, :q, :darken, :fm]
PARAMETER_VALUE_PATTERNS = 
{
  fit: /^(clip|crop)$/,
  h: /^\d+$/,
  w: /^\d+$/,
  q: /^([0-9]|[1-9][0-9]|100)$/,
  darken: /^([0-9]|[1-9][0-9]|100)$/,
  fm: /^(jpg|png|gif)$/,
}

Instance Method Summary collapse

Constructor Details

#initialize(path, parameters) ⇒ ImageProcessor

Returns a new instance of ImageProcessor.



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# File 'lib/mountable_image_server/image_processor.rb', line 27

def initialize(path, parameters)
  @path = path
  @file_format = path.extname.downcase.scan(/[^\.]+/).last
  @parameters = sanitize_parameters(parameters)
end

Instance Method Details

#run(&block) ⇒ Object 



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# File 'lib/mountable_image_server/image_processor.rb', line 33

def run(&block)
  yield(Pathname(path)) and return unless parameters.any?

  parameters[:fit] ||= 'clip'

  if parameters[:fm] && parameters[:fm] == file_format
    parameters.delete(:fm)
  end

  if parameters[:fm]
    extension = ".#{parameters[:fm]}"
  else
    extension = ".#{file_format}"
  end

  if parameters[:fm] && parameters[:fm] != file_format && file_format == 'gif'
    input_path = "#{path}[0]"
  else
    input_path = path
  end

  operations_queue = [
    format_operations,
    resize_operations,
    crop_operations,
    quality_operations,
    darken_operations,
  ].reduce([], :+)

  Tempfile.create(['processed-image', extension]) do |file|
    command = convert(input_path, to: file.path) do
      operations_queue.each do |operation|
        set *operation
      end
    end

    command.run

    yield(Pathname(file.path))
  end
end