Class: ActiveStorage::Variation
- Inherits:
-
Object
- Object
- ActiveStorage::Variation
- Defined in:
- app/models/active_storage/variation.rb
Overview
A set of transformations that can be applied to a blob to create a variant. This class is exposed via the ActiveStorage::Blob#variant method and should rarely be used directly.
In case you do need to use this directly, it's instantiated using a hash of transformations where the key is the command and the value is the arguments. Example:
ActiveStorage::Variation.new(resize: "100x100", monochrome: true, trim: true, rotate: "-90")
You can also combine multiple transformations in one step, e.g. for center-weighted cropping:
ActiveStorage::Variation.new(combine_options: {
resize: "100x100^",
gravity: "center",
crop: "100x100+0+0",
})
A list of all possible transformations is available at www.imagemagick.org/script/mogrify.php.
Instance Attribute Summary collapse
-
#transformations ⇒ Object
readonly
Returns the value of attribute transformations.
Class Method Summary collapse
-
.decode(key) ⇒ Object
Returns a Variation instance with the transformations that were encoded by
encode
. -
.encode(transformations) ⇒ Object
Returns a signed key for the
transformations
, which can be used to refer to a specific variation in a URL or combined key (likeActiveStorage::Variant#key
). -
.wrap(variator) ⇒ Object
Returns a Variation instance based on the given variator.
Instance Method Summary collapse
-
#initialize(transformations) ⇒ Variation
constructor
A new instance of Variation.
-
#key ⇒ Object
Returns a signed key for all the
transformations
that this variation was instantiated with. -
#transform(image) ⇒ Object
Accepts an open MiniMagick image instance, like what's returned by
MiniMagick::Image.read(io)
, and performs thetransformations
against it.
Constructor Details
#initialize(transformations) ⇒ Variation
Returns a new instance of Variation.
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# File 'app/models/active_storage/variation.rb', line 50 def initialize(transformations) @transformations = transformations end |
Instance Attribute Details
#transformations ⇒ Object (readonly)
Returns the value of attribute transformations.
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# File 'app/models/active_storage/variation.rb', line 21 def transformations @transformations end |
Class Method Details
.decode(key) ⇒ Object
Returns a Variation instance with the transformations that were encoded by encode
.
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# File 'app/models/active_storage/variation.rb', line 39 def decode(key) new ActiveStorage.verifier.verify(key, purpose: :variation) end |
.encode(transformations) ⇒ Object
Returns a signed key for the transformations
, which can be used to refer to a specific variation in a URL or combined key (like ActiveStorage::Variant#key
).
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# File 'app/models/active_storage/variation.rb', line 45 def encode(transformations) ActiveStorage.verifier.generate(transformations, purpose: :variation) end |
.wrap(variator) ⇒ Object
Returns a Variation instance based on the given variator. If the variator is a Variation, it is returned unmodified. If it is a String, it is passed to ActiveStorage::Variation.decode. Otherwise, it is assumed to be a transformations Hash and is passed directly to the constructor.
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# File 'app/models/active_storage/variation.rb', line 27 def wrap(variator) case variator when self variator when String decode variator else new variator end end |
Instance Method Details
#key ⇒ Object
Returns a signed key for all the transformations
that this variation was instantiated with.
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# File 'app/models/active_storage/variation.rb', line 73 def key self.class.encode(transformations) end |
#transform(image) ⇒ Object
Accepts an open MiniMagick image instance, like what's returned by MiniMagick::Image.read(io)
, and performs the transformations
against it. The transformed image instance is then returned.
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# File 'app/models/active_storage/variation.rb', line 56 def transform(image) ActiveSupport::Notifications.instrument("transform.active_storage") do transformations.each do |name, argument_or_subtransformations| image.mogrify do |command| if name.to_s == "combine_options" argument_or_subtransformations.each do |subtransformation_name, subtransformation_argument| pass_transform_argument(command, subtransformation_name, subtransformation_argument) end else pass_transform_argument(command, name, argument_or_subtransformations) end end end end end |