Module: CarrierWave::MiniMagick
- Extended by:
- ActiveSupport::Concern
- Defined in:
- lib/carrierwave/processing/mini_magick.rb
Overview
This module simplifies manipulation with MiniMagick by providing a set of convenient helper methods. If you want to use them, you’ll need to require this file:
require 'carrierwave/processing/mini_magick'
And then include it in your uploader:
class MyUploader < CarrierWave::Uploader::Base
include CarrierWave::MiniMagick
end
You can now use the provided helpers:
class MyUploader < CarrierWave::Uploader::Base
include CarrierWave::MiniMagick
process :resize_to_fit => [200, 200]
end
Or create your own helpers with the powerful manipulate! method. Check out the ImageMagick docs at www.imagemagick.org/script/command-line-options.php for more info
class MyUploader < CarrierWave::Uploader::Base
include CarrierWave::MiniMagick
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
Note
MiniMagick is a mini replacement for RMagick that uses the command line tool “mogrify” for image manipulation.
You can find more information here:
mini_magick.rubyforge.org/ and github.com/probablycorey/mini_magick/
Defined Under Namespace
Modules: ClassMethods
Instance Method Summary collapse
-
#convert(format) ⇒ Object
Changes the image encoding format to the given format.
-
#manipulate! ⇒ Object
Manipulate the image with RMagick.
-
#resize_and_pad(width, height, background = :transparent, gravity = 'Center') ⇒ Object
Resize the image to fit within the specified dimensions while retaining the original aspect ratio.
-
#resize_to_fill(width, height, gravity = 'Center') ⇒ Object
From the RMagick documentation: “Resize the image to fit within the specified dimensions while retaining the aspect ratio of the original image.
-
#resize_to_fit(width, height) ⇒ Object
From the RMagick documentation: “Resize the image to fit within the specified dimensions while retaining the original aspect ratio.
-
#resize_to_limit(width, height) ⇒ Object
Resize the image to fit within the specified dimensions while retaining the original aspect ratio.
Instance Method Details
#convert(format) ⇒ Object
Changes the image encoding format to the given format
See www.imagemagick.org/script/command-line-options.php#format
Parameters
- format (#to_s)
-
an abreviation of the format
Yields
- MiniMagick::Image
-
additional manipulations to perform
Examples
image.convert(:png)
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# File 'lib/carrierwave/processing/mini_magick.rb', line 100 def convert(format) manipulate! do |img| img.format(format.to_s.downcase) img = yield(img) if block_given? img end end |
#manipulate! ⇒ 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.
Gotcha
This method assumes that the object responds to current_path
. Any class that this module is mixed into must have a current_path
method. CarrierWave::Uploader does, so you won’t need to worry about this in most cases.
Yields
- MiniMagick::Image
-
manipulations to perform
Raises
- CarrierWave::ProcessingError
-
if manipulation failed.
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# File 'lib/carrierwave/processing/mini_magick.rb', line 251 def manipulate! image = ::MiniMagick::Image.from_file(current_path) image = yield(image) image.write(current_path) ::MiniMagick::Image.from_file(current_path) rescue ::MiniMagick::Error, MiniMagick::Invalid => e raise CarrierWave::ProcessingError.new("Failed to manipulate with MiniMagick, maybe it is not an image? Original Error: #{e}") end |
#resize_and_pad(width, height, background = :transparent, gravity = 'Center') ⇒ 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).
See www.imagemagick.org/script/command-line-options.php#gravity for gravity options.
Parameters
- width (Integer)
-
the width to scale the image to
- height (Integer)
-
the height to scale the image to
- background (String, :transparent)
-
the color of the background as a hexcode, like “#ff45de”
- gravity (String)
-
how to position the image
Yields
- MiniMagick::Image
-
additional manipulations to perform
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# File 'lib/carrierwave/processing/mini_magick.rb', line 214 def resize_and_pad(width, height, background=:transparent, gravity='Center') manipulate! do |img| img. do |cmd| cmd.thumbnail "#{width}x#{height}>" if background == :transparent cmd.background "rgba(0, 0, 0, 0.0)" else cmd.background background end cmd.gravity gravity cmd.extent "#{width}x#{height}" end img = yield(img) if block_given? img end end |
#resize_to_fill(width, height, gravity = 'Center') ⇒ Object
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.”
See even www.imagemagick.org/RMagick/doc/image3.html#resize_to_fill
and
www.clipclip.org/clips/detail/4365/jerrett-net-»-crop_resized-in-rmagick
Parameters
- width (Integer)
-
the width to scale the image to
- height (Integer)
-
the height to scale the image to
Yields
- MiniMagick::Image
-
additional manipulations to perform
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# File 'lib/carrierwave/processing/mini_magick.rb', line 176 def resize_to_fill(width, height, gravity = 'Center') manipulate! do |img| cols, rows = img[:dimensions] img. do |cmd| if width != cols || height != rows scale = [width/cols.to_f, height/rows.to_f].max cols = (scale * (cols + 0.5)).round rows = (scale * (rows + 0.5)).round cmd.resize "#{cols}x#{rows}" end cmd.gravity gravity cmd.extent "#{width}x#{height}" if cols != width || rows != height end img = yield(img) if block_given? img end end |
#resize_to_fit(width, height) ⇒ Object
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.”
See even www.imagemagick.org/RMagick/doc/image3.html#resize_to_fit
Parameters
- width (Integer)
-
the width to scale the image to
- height (Integer)
-
the height to scale the image to
Yields
- MiniMagick::Image
-
additional manipulations to perform
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# File 'lib/carrierwave/processing/mini_magick.rb', line 148 def resize_to_fit(width, height) manipulate! do |img| img.resize "#{width}x#{height}" img = yield(img) if block_given? img end end |
#resize_to_limit(width, height) ⇒ Object
Resize the image to fit within the specified dimensions while retaining the original aspect ratio. Will only resize the image if it is larger than the specified dimensions. The resulting 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
Yields
- MiniMagick::Image
-
additional manipulations to perform
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# File 'lib/carrierwave/processing/mini_magick.rb', line 123 def resize_to_limit(width, height) manipulate! do |img| img.resize "#{width}x#{height}>" img = yield(img) if block_given? img end end |