Module: CarrierWave::RMagick

Defined in:
lib/carrierwave/processing/rmagick.rb

Overview

This module simplifies manipulation with RMagick by providing a set of convenient helper methods. If you want to use them, you’ll need to require this file

require 'carrierwave/processing/rmagick'

And then include it in your uploader

MyUploade < CarrierWave::Uploader
  include CarrierWave::RMagick
end

You can now use the provided helpers:

MyUploade < CarrierWave::Uploader
  include CarrierWave::RMagick

  process :resize_to_fit => [200, 200] 
end

Or create your own helpers with the powerful manipulate! method. Check out the RMagick docs at www.imagemagick.org/RMagick/doc/ for more info

MyUploade < CarrierWave::Uploader
  include CarrierWave::RMagick

  process :do_stuff => 10.0

  def do_stuff(blur_factor)
    manipulate! do |img|
      img = img.sepiatone
      img = img.auto_orient
      img = img.radial_blur(blur_factor)
    end
  end
end

Instance Method Summary collapse

Instance Method Details

#convert(format) {|img| ... } ⇒ Object

Changes the image encoding format to the given format

Examples:

image.convert(:png)

Parameters:

  • format (#to_s) —

    an abreviation of the format

Yield Parameters:

  • img (Magick::Image) —

    additional manipulations to perform

See Also:



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# File 'lib/carrierwave/processing/rmagick.rb', line 55

def convert(format)
  manipulate! do |img|
    img.format = format.to_s.upcase
    img = yield(img) if block_given?
    img
  end
end

#manipulate! {|img| ... } ⇒ Object

Manipulate the image with RMagick. This method will load up an image and then pass each of its frames to the supplied block. It will then save the image to disk.

Note: This method assumes that the object responds to current_path any class that this is mixed into must have a current_path method.

Yield Parameters:

  • img (Magick::Image) —

    manipulations to perform

Raises:



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# File 'lib/carrierwave/processing/rmagick.rb', line 144

def manipulate!
  image = ::Magick::Image.read(current_path)

  if image.size > 1
    list = ::Magick::ImageList.new
    image.each do |frame|
      list << yield( frame )
    end
    list.write(current_path)
  else
    yield( image.first ).write(current_path)
  end
rescue ::Magick::ImageMagickError => e
  raise CarrierWave::ProcessingError.new("Failed to manipulate with rmagick, maybe it is not an image? Original Error: #{e}")
end

#resize_and_pad(width, height, background = :transparent, gravity = ::Magick::CenterGravity) {|img| ... } ⇒ Object

Resize the image to fit within the specified dimensions while retaining the original aspect ratio. If necessary will pad the remaining area with the given color, which defaults to transparent (for gif and png, white for jpeg).

Parameters:

  • width (Integer) —

    the width to scale the image to

  • height (Integer) —

    the height to scale the image to

  • background (String, :transparent) (defaults to: :transparent) —

    the color of the background as a hexcode, like “#ff45de”

  • gravity (Magick::GravityType) (defaults to: ::Magick::CenterGravity) —

    how to position the image

Yield Parameters:

  • img (Magick::Image) —

    additional manipulations to perform



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# File 'lib/carrierwave/processing/rmagick.rb', line 118

def resize_and_pad(width, height, background=:transparent, gravity=::Magick::CenterGravity)
  manipulate! do |img|
    img.resize_to_fit!(width, height)
    new_img = ::Magick::Image.new(width, height)
    if background == :transparent
      new_img = new_img.matte_floodfill(1, 1)
    else
      new_img = new_img.color_floodfill(1, 1, ::Magick::Pixel.from_color(background))
    end
    new_img = new_img.composite(img, gravity, ::Magick::OverCompositeOp)
    new_img = yield(new_img) if block_given?
    new_img
  end
end

#resize_to_fill(width, height) {|img| ... } ⇒ Object Also known as: crop_resized

From the RMagick documentation: “Resize the image to fit within the specified dimensions while retaining the aspect ratio of the original image. If necessary, crop the image in the larger dimension.”

Parameters:

  • width (Integer) —

    the width to scale the image to

  • height (Integer) —

    the height to scale the image to

Yield Parameters:

  • img (Magick::Image) —

    additional manipulations to perform

See Also:



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# File 'lib/carrierwave/processing/rmagick.rb', line 96

def resize_to_fill(width, height)
  manipulate! do |img|
    img.resize_to_fill!(width, height)
    img = yield(img) if block_given?
    img
  end
end

#resize_to_fit(width, height) {|img| ... } ⇒ Object Also known as: resize

From the RMagick documentation: “Resize the image to fit within the specified dimensions while retaining the original aspect ratio. The image may be shorter or narrower than specified in the smaller dimension but will not be larger than the specified values.”

Parameters:

  • width (Integer) —

    the width to scale the image to

  • height (Integer) —

    the height to scale the image to

Yield Parameters:

  • img (Magick::Image) —

    additional manipulations to perform

See Also:



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# File 'lib/carrierwave/processing/rmagick.rb', line 75

def resize_to_fit(width, height)
  manipulate! do |img|
    img.resize_to_fit!(width, height)
    img = yield(img) if block_given?
    img
  end
end