ruby-on-rails - tutorial - file upload with carrierwave

Carrierwave RMagick no elimina la transparencia en convertir a jpg

Question

Estoy intentando subir un PNG y guardar un montón de miniaturas. Las miniaturas deberían ser JPG y no tener ninguna transparencia. De alguna manera, el archivo se guarda como jpg pero tiene transparencia ...

Aquí está mi Uploader:

# encoding: utf-8

class WinePhotoUploader < CarrierWave::Uploader::Base

    # Include RMagick or MiniMagick support:
    include CarrierWave::RMagick
    # include CarrierWave::MiniMagick

    # Choose what kind of storage to use for this uploader:
    storage :file
    # storage :fog

    # Override the directory where uploaded files will be stored.
    # This is a sensible default for uploaders that are meant to be mounted:
    def store_dir
    "assets/wines/#{version_name}"
    end

    CarrierWave::SanitizedFile.sanitize_regexp = /[^[:word:]/./-/+]/

    # Provide a default URL as a default if there hasn''t been a file uploaded:
    def default_url
    # For Rails 3.1+ asset pipeline compatibility:
    ActionController::Base.helpers.asset_path("pages/wines/#{version_name}/default.png")
    end

    process :for_all
    process :convert => ''jpg''

    version :croppable, :if => :new_upload? do
    process :resize_and_pad => [1200, 1200, ''white'']
    end

    version :show, :if => :new_upload? do
    process :resize_to_fit => [nil, ''425'']
    end

    version :general, :from_version => :show, :if => :new_upload? do
    process :resize_and_pad => [150, 375, ''white'']
    end

    version :thumb, :from_version => :croppable, :if => :cropping? do
    process :rotate_to => [-30]
    process :crop_via_model
    process :resize_to_fit => [150, 150]
    end

    def for_all
    manipulate! do |img|
        img.trim
        img.gravity = Magick::CenterGravity

        # I only use these two because this shit isn''t working...these don''t seem to help!
        # Neither does the flatten method...even though other posts on stackoverflow.com say
        # that it works.
        img.background_color = ''white''
        img.alpha Magick::OpaqueAlphaChannel

        img.unsharp_mask 0.3, 0.3, 5, 0
        img
    end
    end

    def extend_to(w, h)
    manipulate! do |img|
        img.gravity = Magick::CenterGravity
        img.extent w, h
        img
    end
    end

    def rotate_to(deg)
    manipulate! do |img|
        img.gravity = Magick::CenterGravity
        img.distort Magick::ScaleRotateTranslateDistortion, deg
        #img.repage # WTF?!?!?!? No repage method?!
        img
    end
    end

    def crop_via_model
    manipulate! do |img|
        img.gravity = Magick::CenterGravity
        img.crop model.crop_x.to_i, model.crop_y.to_i, model.crop_w.to_i, model.crop_h.to_i
        img
    end
    end

    def flatten
    manipulate! do |img|
        img_list = Magick::ImageList.new
        img_list.from_blob img.to_blob
        img_list.new_image(img_list.first.columns, img_list.first.rows) { self.background_color = "white" } # Create new "layer" with white background and size of original image
        img = img_list.reverse.flatten_images
        img
    end
    end

    def new_upload? picture
    !model.cropping?
    end
    def cropping? picture
    model.cropping?
    end

    # Add a white list of extensions which are allowed to be uploaded.
    # For images you might use something like this:
    def extension_white_list
    %w(jpg jpeg gif png tif)
    end

    # Override the filename of the uploaded files:
    # Avoid using model.id or version_name here, see uploader/store.rb for details.
    def filename
    "#{ model.get_permalink(:normalized => true) }.jpg"
    end

    # Remove this when https://github.com/carrierwaveuploader/carrierwave/issues/1164 is solved.
    def recreate_versions!(*versions)
    if versions.any?
        from_versions = versions.group_by { |v| self.class.versions[v][:options][:from_version] }
        from_versions.each do |from, versions|
        next if from.nil?
        file = CarrierWave::SanitizedFile.new(self.versions[from.to_sym].file)
        store_versions!(file, versions)
        end
    else
        super(*versions)
    end
    end

end

Oh ... y aparentemente carrierwave no parece querer registrar nada, así que no puedo decir lo que está haciendo.

Answer 1

Parece que hay una peculiaridad con imagemagick y el orden de las operaciones al convertir tipos de archivos.

El problema completo de github se puede encontrar aquí: https://github.com/carrierwaveuploader/carrierwave/issues/133#issuecomment-615254

Básicamente manipulate se llama una vez por cada process que tiene. manipulate abre la ruta actual del archivo, realiza cambios y luego escribe. Debido a esto, parece que las líneas de process que se llaman después de la conversión de formato se realizan en el archivo original, no en el archivo recién convertido.

Para solucionar esto, debe realizar todas sus operaciones de process dentro de un solo bloque de manipulate o asegurarse de que la conversión sea el último process en ejecutarse.

El ejemplo de esto del problema de Github es:

process :convert_and_scale

def convert_and_scale
  manipulate! do |img|
    img.format ''png''
    img.resize ''100x32''
    img
  end
end