问题是,当图像安装在模型上时,watemark def 中的变量,在上传器类中,不可用。就是这样做的。我正在使用 mongoid 来处理 mongoDB。我在模型中设置了一个参数,它将保存我想要的值,例如。the_current_model.gallery.watermark.image_url 的值。此参数将是 user_image。
class Asset
include Mongoid::Document
mount_uploader :image, AssetUploader
field :user_image
attr_accessible :user_image
after_save :mark_it
private
def mark_it
image.recreate_versions! if user_image.present?
end
end
解决这个问题的关键是在将数据保存在数据库中之后重新创建图像(正如您在调用 mark_it def 的模型上看到的那样),并且允许将参数 user_image 用于您的上传器类。
class AssetUploader < CarrierWave::Uploader::Base
include CarrierWave::RMagick
storage :file
# storage :fog
after :cache, :unlink_original_cache
# 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
"uploads/#{model.class.to_s.underscore}/#{mounted_as}/#{model.id}"
end
# Provide a default URL as a default if there hasn't been a file uploaded:
# def default_url
# "/images/fallback/" + [version_name, "default.png"].compact.join('_')
# end
process :resize_to_fit => [800, 800]
process :quality => 80
version :thumb do
process :resize_to_fit => [200, 200]
end
version :large do
process :watermark
end
def watermark
if model.user_name.present?
manipulate! do |img|
text = Magick::Draw.new
text.gravity = Magick::CenterGravity
text.fill = 'white'
text.pointsize = 40
text.stroke = 'none'
text.annotate(img, 0, 0, 0, 0, "#{model.user_name}")
img
end
end
end
def unlink_original(file)
File.delete path if version_name.blank?
end
def unlink_original_cache(file)
File.delete if version_name.blank?
end
def extension_white_list
%w(jpg jpeg gif png)
end
# Override the filename of the uploaded files:
# Avoid using model.id or version_name here, see uploader/store.rb for details.
# def filename
# "something.jpg" if original_filename
# end
end
现在关键在这里:
def watermark
if model.user_name.present?
manipulate! do |img|
text = Magick::Draw.new
text.gravity = Magick::CenterGravity
text.fill = 'white'
text.pointsize = 40
text.stroke = 'none'
text.annotate(img, 0, 0, 0, 0, "#{model.user_name}")
img
end
end
end
如果设置了模型上的 user_name 参数(在数据库上创建),则方法 watermark 仅创建带有水印的图像。因此,当数据保存在数据库上时,此参数可供您的上传程序类根据需要使用。
我就是这么做的,而且效果很好!我希望它可以帮助!