我需要有条件地创建已上传图像的不同版本。我知道Carrierwave支持这个功能,但我的要求有些棘手。
对于每个上传的图像,我需要创建2个版本,并根据条件缩放原始图像。
以下代码将更好地说明我的意图:
version :leftright, :if => :image? do
process :resize_to_fill => [667*2, 778*2] ,:if => :is_retina_resolution?
process :resize_to_fill => [667, 778] ,:if => !:is_retina_resolution?
end
version :updown, :if => :image? do
process :resize_to_fill => [1024*2, 487*2] ,:if => :is_retina_resolution?
process :resize_to_fill => [1024, 487] ,:if => !:is_retina_resolution?
end
#resize the original image
process :resize_to_fill => [1024*2, 768*2] ,:if => :is_retina_resolution?
process :resize_to_fill => [1024, 768] ,:if => !:is_retina_resolution?
def is_retina_resolution?(new_file)
image = MiniMagick::Image.open(new_file.file)
true if image[:height] >= 1536 and image[:width] >= 2048
end
似乎这个不起作用。Carrierwave 抛出了以下错误:
Errno::ENOENT - 没有这样的文件或目录 - #<ActionDispatch::Http::UploadedFile:0xe41d508>
我尝试了另一种变化:
version :leftright, :if => :image? do
if :is_retina_resolution?
process :resize_to_fill => [667*2, 778*2]
else
process :resize_to_fill => [667, 778]
end
end
version :updown, :if => :image? do
if :is_retina_resolution?
process :resize_to_fill => [1024*2, 487*2]
else
process :resize_to_fill => [1024, 487]
end
end
def is_retina_resolution?(new_file)
image = MiniMagick::Image.open(new_file)
true if image[:height] >= 1536 and image[:width] >= 2048
end
这段代码不会报错。但是它总是生成 retina尺寸
的图片(第一种情况)。
因此,我尝试了另一种变化:
version :leftright, :if => :image? && :is_retina_resolution do
process :resize_to_fill => [667*2, 778*2]
end
version :leftright, :if => :image? && !:is_retina_resolution do
process :resize_to_fill => [667, 778]
end
version :updown, :if => :image? && :is_retina_resolution do
process :resize_to_fill => [1024*2, 487*2]
end
version :updown, :if => :image? && !:is_retina_resolution do
process :resize_to_fill => [1024, 487]
end
这段代码没有抛出任何错误,也没有创建任何版本。
有人可以帮我吗?
更新:
根据@DMKE的建议,我进行了更改,现在它可以正常工作。
version :leftright, :if => :image? do
process :resize_to_fill => [667*2, 778*2] ,:if => :is_retina_resolution?
process :resize_to_fill => [667, 778] ,:if => :is_not_retina_resolution?
end
version :updown, :if => :image? do
process :resize_to_fill => [1024*2, 487*2] ,:if => :is_retina_resolution?
process :resize_to_fill => [1024, 487] ,:if => :is_not_retina_resolution?
end
#resize the original image
process :resize_to_fill => [1024*2, 768*2] ,:if => :image_and_retina?
process :resize_to_fill => [1024, 768] ,:if => :image_and_not_retina?
process :if => :not_image?
def image_and_retina?(img)
is_img = image? img
return false unless is_img
return is_retina_resolution?(img)
end
def image_and_not_retina?(img)
is_img = image? img
return false unless is_img
return !is_retina_resolution?(img)
end
# returns true if image file
def image?(new_file)
self.file.content_type.include? 'image'
end
def not_image?(new_file)
!self.file.content_type.include? 'image'
end
def is_retina_resolution?(new_file)
image = MiniMagick::Image.open(self.file.file)
true if image[:height] >= 1536 and image[:width] >= 2048
end
def is_not_retina_resolution?(new_file)
image = MiniMagick::Image.open(self.file.file)
true if image[:height] < 1536 and image[:width] < 2048
end