Creating an image per page from a PDF

[Ibrahim Awwal]

Hi,

I'm trying to do something where I upload a PDF file to my Rails
application, and the uploader splits the PDF into N files, one image
file for each page. I can do this trivially with Rmagick by itself by
just making an ImageList with the PDF and then saving the individual
pages, but now I'm wondering what the "right" way to do this using
CarrierWave would be. Should I be using manipulate! somehow? This bug
report seems to indicate that it should be possible, but it doesn't
seem to do anything for me. https://github.com/jnicklas/carrierwave/pull/691

I tried doing this in my uploader:

process :split

def split
manipulate! do |img, index|
img = yield(img) if block_given?
img
end
end

not really knowing what I'm doing, but this didn't really do anything
for me. Should I just call img.write(whateverfilename) in manipulate,
or is there a better way? I thought it would be convenient if each
page was saved as a version but I can't call version inside the
manipulate!'s block. Apologies for severely abusing programming
paradigms I'm sure,

-Ibrahim

[Lee Jarvis]

Hi,

Unfortunately I'm going through the same issue. Did you manage to solve this? There doesn't appear to be much support for PDF manipulation.

[Jacob Tjørnholm]

Hi, 

Have a look at the source for manipulate!: 

https://github.com/jnicklas/carrierwave/blob/master/lib/carrierwave/processing/rmagick.rb#L278

As you can see, if RMagick reports size > 1 for the "image", your block is yielded for each frame. 

So yes, I guess you should be able to simply save each image from your block. 

I don't know about storing individual versions, though...

/Jacob

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[Simon Bailey]

I have now tried quite a few approaches to achieve the required result with no dice. If any experienced heads could help me out here it would be most appreciated:

http://stackoverflow.com/questions/10988023/multipage-pdf-processing-to-png-using-carrierwave

Simon

On Wednesday, 2 May 2012 13:24:03 UTC+1, Ibrahim Awwal wrote:

[Simon Bailey]

Ok seems I have a solution to writing the images from the pdf conversion, it doesn't feel clean but suggestions on refining would be appreciated:

def extract(format)

    cache_stored_file! if !cached?

    # Manually create upload dir as its not created at this point

    FileUtils.mkdir_p "#{Rails.root}/#{store_dir}" 

    images = Magick::ImageList.new(current_path)

    images.write "#{Rails.root}/#{store_dir}/#{filename}"

end

[Simon Bailey]

Damn that is a wrong solution, when I use #{store_dir} it still fails to write the files to the same directory Carrierwave is uploading to i.e. public/uploads/.. so when I transitioned to S3 it just wrote them to the Rails application root /uploads/.. :(

[Ben Ridgway]

Hi Gents. Has anyone managed to resolve this issue a year on? I'm trying to do something similar by taking a multipage PDF in and converting each page to PNG images. 

Thanks 

Ben

On Friday, March 15, 2013 3:03:30 AM UTC+9, James Summerill wrote:

Did you ever find out why this happening and is there a fix for it?
I'm having the same issue of Carrierwave not saving the the specified store_dir