Class: ImageProcessing::Vips::Processor

Inherits:
Processor
  • Object
show all
Defined in:
lib/image_processing/vips.rb

Defined Under Namespace

Modules: Utils

Constant Summary collapse

SHARPEN_MASK =

Default sharpening mask that provides a fast and mild sharpen.

::Vips::Image.new_from_array [[-1, -1, -1],
[-1, 32, -1],
[-1, -1, -1]], 24

Class Method Summary collapse

Instance Method Summary collapse

Methods inherited from Processor

accumulator, apply_operation, #custom, #initialize

Constructor Details

This class inherits a constructor from ImageProcessing::Processor

Class Method Details

.load_image(path_or_image, autorot: true, **options) ⇒ Object

Loads the image on disk into a Vips::Image object. Accepts additional loader-specific options (e.g. interlacing). Afterwards auto-rotates the image to be upright.



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# File 'lib/image_processing/vips.rb', line 30

def self.load_image(path_or_image, autorot: true, **options)
  if path_or_image.is_a?(::Vips::Image)
    image = path_or_image
  else
    source_path = path_or_image
    options     = Utils.select_valid_loader_options(source_path, options)

    image = ::Vips::Image.new_from_file(source_path, **options)
  end

  image = image.autorot if autorot && !options.key?(:autorotate)
  image
end

.save_image(image, destination_path, quality: nil, **options) ⇒ Object

Writes the Vips::Image object to disk. This starts the processing pipeline defined in the Vips::Image object. Accepts additional saver-specific options (e.g. quality).



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# File 'lib/image_processing/vips.rb', line 47

def self.save_image(image, destination_path, quality: nil, **options)
  options = options.merge(Q: quality) if quality
  options = Utils.select_valid_saver_options(destination_path, options)

  image.write_to_file(destination_path, **options)
end

Instance Method Details

#composite(overlay, _mode = nil, mode: "over", gravity: "north-west", offset: nil, **options) ⇒ Object

Overlays the specified image over the current one. Supports specifying composite mode, direction or offset of the overlay image.



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# File 'lib/image_processing/vips.rb', line 89

def composite(overlay, _mode = nil, mode: "over", gravity: "north-west", offset: nil, **options)
  # if the mode argument is given, call the original Vips::Image#composite
  if _mode
    overlay = [overlay] unless overlay.is_a?(Array)
    overlay = overlay.map { |object| convert_to_image(object, "overlay") }

    return image.composite(overlay, _mode, **options)
  end

  overlay = convert_to_image(overlay, "overlay")
  # add alpha channel so that #gravity can use a transparent background
  overlay = overlay.add_alpha unless overlay.has_alpha?

  # apply offset with correct gravity and make remainder transparent
  if offset
    opposite_gravity = gravity.to_s.gsub(/\w+/, "north"=>"south", "south"=>"north", "east"=>"west", "west"=>"east")
    overlay = overlay.gravity(opposite_gravity, overlay.width + offset.first, overlay.height + offset.last)
  end

  # create image-sized transparent background and apply specified gravity
  overlay = overlay.gravity(gravity, image.width, image.height)

  # apply the composition
  image.composite(overlay, mode, **options)
end

#resize_and_pad(width, height, gravity: "centre", extend: nil, background: nil, alpha: nil, **options) ⇒ Object

Resizes the image to fit within the specified dimensions and fills the remaining area with the specified background color.



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# File 'lib/image_processing/vips.rb', line 74

def resize_and_pad(width, height, gravity: "centre", extend: nil, background: nil, alpha: nil, **options)
  image = thumbnail(width, height, **options)
  image = image.add_alpha if alpha && !image.has_alpha?
  image.gravity(gravity, width, height, extend: extend, background: background)
end

#resize_to_fill(width, height, **options) ⇒ Object

Resizes the image to fill the specified dimensions, applying any necessary cropping.



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# File 'lib/image_processing/vips.rb', line 68

def resize_to_fill(width, height, **options)
  thumbnail(width, height, crop: :centre, **options)
end

#resize_to_fit(width, height, **options) ⇒ Object

Resizes the image to fit within the specified dimensions.



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# File 'lib/image_processing/vips.rb', line 61

def resize_to_fit(width, height, **options)
  width, height = default_dimensions(width, height)
  thumbnail(width, height, **options)
end

#resize_to_limit(width, height, **options) ⇒ Object

Resizes the image to not be larger than the specified dimensions.



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# File 'lib/image_processing/vips.rb', line 55

def resize_to_limit(width, height, **options)
  width, height = default_dimensions(width, height)
  thumbnail(width, height, size: :down, **options)
end

#rotate(degrees, **options) ⇒ Object

Rotates the image by an arbitrary angle. Additional options can be specified, such as background colors to fill in the gaps when rotating with an angle which is not a multiple of 90 degrees.



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# File 'lib/image_processing/vips.rb', line 83

def rotate(degrees, **options)
  image.similarity(angle: degrees, **options)
end

#set(*args) ⇒ Object

make Vips::Image#set, #set_type, and #set_value chainable



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# File 'lib/image_processing/vips.rb', line 116

def set(*args)       image.tap { |img| img.set(*args) }       end

#set_type(*args) ⇒ Object 



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# File 'lib/image_processing/vips.rb', line 117

def set_type(*args)  image.tap { |img| img.set_type(*args) }  end

#set_value(*args) ⇒ Object 



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# File 'lib/image_processing/vips.rb', line 118

def set_value(*args) image.tap { |img| img.set_value(*args) } end